Merge remote-tracking branch 'upstream/master' into create-grpc-c++-podspec

7 years ago · bc4b7891c8
parent 61bb29f141 fb309a966b
commit bc4b7891c8
476 changed files with 8923 additions and 7136 deletions
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@ -1,7 +1,7 @@
 # Auto-generated by the tools/mkowners/mkowners.py tool
 # Uses OWNERS files in different modules throughout the
 # repository as the source of truth for module ownership.
-/**/OWNERS @markdroth @nicolasnoble @ctiller
-/bazel/** @nicolasnoble @dgquintas @ctiller
-/src/core/ext/filters/client_channel/** @markdroth @dgquintas @ctiller
+/**/OWNERS @markdroth @nicolasnoble @a11r
+/bazel/** @nicolasnoble @dgquintas @a11r @vjpai
+/src/core/ext/filters/client_channel/** @markdroth @dgquintas @a11r
 /tools/run_tests/performance/** @ncteisen @matt-kwong @ctiller
--- a/.gitignore
+++ b/.gitignore
@ -130,3 +130,5 @@ bm_diff_new/
 bm_diff_old/
 bm_*.json

+# cmake build files
+/cmake/build
--- a/193
+++ b/193
@ -38,17 +38,27 @@ config_setting(
    values = {"define": "grpc_no_ares=true"},
 )

+config_setting(
+    name = "grpc_allow_exceptions",
+    values = {"define": "GRPC_ALLOW_EXCEPTIONS=1"},
+)
+
+config_setting(
+    name = "grpc_disallow_exceptions",
+    values = {"define": "GRPC_ALLOW_EXCEPTIONS=0"},
+)
+
 config_setting(
    name = "remote_execution",
    values = {"define": "GRPC_PORT_ISOLATED_RUNTIME=1"},
 )

 # This should be updated along with build.yaml
-g_stands_for = "glossy"
+g_stands_for = "glamorous"

 core_version = "5.0.0-dev"

-version = "1.9.0-dev"
+version = "1.10.0-dev"

 GPR_PUBLIC_HDRS = [
    "include/grpc/support/alloc.h",
@ -438,75 +448,67 @@ grpc_cc_library(
    srcs = [
        "src/core/lib/profiling/basic_timers.cc",
        "src/core/lib/profiling/stap_timers.cc",
-        "src/core/lib/support/alloc.cc",
-        "src/core/lib/support/arena.cc",
-        "src/core/lib/support/atm.cc",
-        "src/core/lib/support/avl.cc",
-        "src/core/lib/support/cmdline.cc",
-        "src/core/lib/support/cpu_iphone.cc",
-        "src/core/lib/support/cpu_linux.cc",
-        "src/core/lib/support/cpu_posix.cc",
-        "src/core/lib/support/cpu_windows.cc",
-        "src/core/lib/support/env_linux.cc",
-        "src/core/lib/support/env_posix.cc",
-        "src/core/lib/support/env_windows.cc",
-        "src/core/lib/support/fork.cc",
-        "src/core/lib/support/host_port.cc",
-        "src/core/lib/support/log.cc",
-        "src/core/lib/support/log_android.cc",
-        "src/core/lib/support/log_linux.cc",
-        "src/core/lib/support/log_posix.cc",
-        "src/core/lib/support/log_windows.cc",
-        "src/core/lib/support/mpscq.cc",
-        "src/core/lib/support/murmur_hash.cc",
-        "src/core/lib/support/string.cc",
-        "src/core/lib/support/string_posix.cc",
-        "src/core/lib/support/string_util_windows.cc",
-        "src/core/lib/support/string_windows.cc",
-        "src/core/lib/support/subprocess_posix.cc",
-        "src/core/lib/support/subprocess_windows.cc",
-        "src/core/lib/support/sync.cc",
-        "src/core/lib/support/sync_posix.cc",
-        "src/core/lib/support/sync_windows.cc",
-        "src/core/lib/support/thd.cc",
-        "src/core/lib/support/thd_posix.cc",
-        "src/core/lib/support/thd_windows.cc",
-        "src/core/lib/support/time.cc",
-        "src/core/lib/support/time_posix.cc",
-        "src/core/lib/support/time_precise.cc",
-        "src/core/lib/support/time_windows.cc",
-        "src/core/lib/support/tls_pthread.cc",
-        "src/core/lib/support/tmpfile_msys.cc",
-        "src/core/lib/support/tmpfile_posix.cc",
-        "src/core/lib/support/tmpfile_windows.cc",
-        "src/core/lib/support/wrap_memcpy.cc",
+        "src/core/lib/gpr/alloc.cc",
+        "src/core/lib/gpr/arena.cc",
+        "src/core/lib/gpr/atm.cc",
+        "src/core/lib/gpr/avl.cc",
+        "src/core/lib/gpr/cmdline.cc",
+        "src/core/lib/gpr/cpu_iphone.cc",
+        "src/core/lib/gpr/cpu_linux.cc",
+        "src/core/lib/gpr/cpu_posix.cc",
+        "src/core/lib/gpr/cpu_windows.cc",
+        "src/core/lib/gpr/env_linux.cc",
+        "src/core/lib/gpr/env_posix.cc",
+        "src/core/lib/gpr/env_windows.cc",
+        "src/core/lib/gpr/fork.cc",
+        "src/core/lib/gpr/host_port.cc",
+        "src/core/lib/gpr/log.cc",
+        "src/core/lib/gpr/log_android.cc",
+        "src/core/lib/gpr/log_linux.cc",
+        "src/core/lib/gpr/log_posix.cc",
+        "src/core/lib/gpr/log_windows.cc",
+        "src/core/lib/gpr/mpscq.cc",
+        "src/core/lib/gpr/murmur_hash.cc",
+        "src/core/lib/gpr/string.cc",
+        "src/core/lib/gpr/string_posix.cc",
+        "src/core/lib/gpr/string_util_windows.cc",
+        "src/core/lib/gpr/string_windows.cc",
+        "src/core/lib/gpr/subprocess_posix.cc",
+        "src/core/lib/gpr/subprocess_windows.cc",
+        "src/core/lib/gpr/sync.cc",
+        "src/core/lib/gpr/sync_posix.cc",
+        "src/core/lib/gpr/sync_windows.cc",
+        "src/core/lib/gpr/thd.cc",
+        "src/core/lib/gpr/thd_posix.cc",
+        "src/core/lib/gpr/thd_windows.cc",
+        "src/core/lib/gpr/time.cc",
+        "src/core/lib/gpr/time_posix.cc",
+        "src/core/lib/gpr/time_precise.cc",
+        "src/core/lib/gpr/time_windows.cc",
+        "src/core/lib/gpr/tls_pthread.cc",
+        "src/core/lib/gpr/tmpfile_msys.cc",
+        "src/core/lib/gpr/tmpfile_posix.cc",
+        "src/core/lib/gpr/tmpfile_windows.cc",
+        "src/core/lib/gpr/wrap_memcpy.cc",
    ],
    hdrs = [
        "src/core/lib/profiling/timers.h",
-        "src/core/lib/support/abstract.h",
-        "src/core/lib/support/arena.h",
-        "src/core/lib/support/atomic.h",
-        "src/core/lib/support/atomic_with_atm.h",
-        "src/core/lib/support/atomic_with_std.h",
-        "src/core/lib/support/env.h",
-        "src/core/lib/support/fork.h",
-        "src/core/lib/support/manual_constructor.h",
-        "src/core/lib/support/memory.h",
-        "src/core/lib/support/mpscq.h",
-        "src/core/lib/support/murmur_hash.h",
-        "src/core/lib/support/spinlock.h",
-        "src/core/lib/support/string.h",
-        "src/core/lib/support/string_windows.h",
-        "src/core/lib/support/thd_internal.h",
-        "src/core/lib/support/time_precise.h",
-        "src/core/lib/support/tmpfile.h",
-        "src/core/lib/support/vector.h",
+        "src/core/lib/gpr/arena.h",
+        "src/core/lib/gpr/env.h",
+        "src/core/lib/gpr/fork.h",
+        "src/core/lib/gpr/mpscq.h",
+        "src/core/lib/gpr/murmur_hash.h",
+        "src/core/lib/gpr/spinlock.h",
+        "src/core/lib/gpr/string.h",
+        "src/core/lib/gpr/string_windows.h",
+        "src/core/lib/gpr/thd_internal.h",
+        "src/core/lib/gpr/time_precise.h",
+        "src/core/lib/gpr/tmpfile.h",
    ],
    language = "c++",
    public_hdrs = GPR_PUBLIC_HDRS,
    deps = [
        "gpr_codegen",
-        "@com_google_absl//absl/container:inlined_vector",
    ],
 )

@ -542,26 +544,77 @@ grpc_cc_library(
    ],
 )

+grpc_cc_library(
+    name = "gpr++_base",
+    language = "c++",
+    public_hdrs = [
+        "src/core/lib/gprpp/abstract.h",
+        "src/core/lib/gprpp/manual_constructor.h",
+        "src/core/lib/gprpp/memory.h",
+    ],
+)
+
+grpc_cc_library(
+    name = "atomic",
+    language = "c++",
+    public_hdrs = [
+        "src/core/lib/gprpp/atomic.h",
+    ],
+    hdrs = [
+        "src/core/lib/gprpp/atomic_with_atm.h",
+        "src/core/lib/gprpp/atomic_with_std.h",
+    ],
+    deps = [
+        "gpr",
+    ],
+)
+
+grpc_cc_library(
+    name = "inlined_vector",
+    language = "c++",
+    public_hdrs = [
+        "src/core/lib/gprpp/inlined_vector.h",
+    ],
+    deps = [
+        "gpr++_base",
+    ],
+)
+
 grpc_cc_library(
    name = "debug_location",
-    public_hdrs = ["src/core/lib/support/debug_location.h"],
    language = "c++",
+    public_hdrs = ["src/core/lib/gprpp/debug_location.h"],
 )

 grpc_cc_library(
-    name = "ref_counted",
-    public_hdrs = ["src/core/lib/support/ref_counted.h"],
+    name = "orphanable",
    language = "c++",
+    public_hdrs = ["src/core/lib/gprpp/orphanable.h"],
    deps = [
+        "debug_location",
+        "gpr++_base",
        "grpc_trace",
+    ],
+)
+
+grpc_cc_library(
+    name = "ref_counted",
+    language = "c++",
+    public_hdrs = ["src/core/lib/gprpp/ref_counted.h"],
+    deps = [
        "debug_location",
+        "gpr++_base",
+        "grpc_trace",
    ],
 )

 grpc_cc_library(
    name = "ref_counted_ptr",
-    public_hdrs = ["src/core/lib/support/ref_counted_ptr.h"],
    language = "c++",
+    public_hdrs = ["src/core/lib/gprpp/ref_counted_ptr.h"],
+    deps = [
+        "gpr++_base",
+    ],
 )

 grpc_cc_library(
@ -828,6 +881,7 @@ grpc_cc_library(
    public_hdrs = GRPC_PUBLIC_HDRS,
    deps = [
        "gpr_base",
+        "gpr++_base",
        "grpc_codegen",
        "grpc_trace",
    ],
@ -840,6 +894,7 @@ grpc_cc_library(
    ],
    language = "c++",
    deps = [
+        "atomic",
        "grpc_base_c",
    ],
 )
@ -919,6 +974,8 @@ grpc_cc_library(
    deps = [
        "grpc_base",
        "grpc_deadline_filter",
+        "ref_counted",
+        "ref_counted_ptr",
    ],
 )

@ -1006,7 +1063,6 @@ grpc_cc_library(
        "include/grpc/impl/codegen/byte_buffer_reader.h",
        "include/grpc/impl/codegen/compression_types.h",
        "include/grpc/impl/codegen/connectivity_state.h",
-        "include/grpc/impl/codegen/exec_ctx_fwd.h",
        "include/grpc/impl/codegen/grpc_types.h",
        "include/grpc/impl/codegen/propagation_bits.h",
        "include/grpc/impl/codegen/status.h",
@ -1299,6 +1355,7 @@ grpc_cc_library(
    ],
    language = "c++",
    deps = [
+        "gpr++_base",
        "grpc_base",
        "grpc_http_filters",
        "grpc_transport_chttp2_alpn",
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@ -2,53 +2,92 @@

 We definitely welcome your patches and contributions to gRPC!

-If you are new to github, please start by reading [Pull Request howto](https://help.github.com/articles/about-pull-requests/)
+If you are new to github, please start by reading [Pull Request
+howto](https://help.github.com/articles/about-pull-requests/)

 ## Legal requirements

 In order to protect both you and ourselves, you will need to sign the
-[Contributor License Agreement](https://identity.linuxfoundation.org/projects/cncf).
+[Contributor License
+Agreement](https://identity.linuxfoundation.org/projects/cncf).

 ## Running tests

-Use `tools/run_tests/run_tests.py` script to run the unit tests.
-See [tools/run_tests](tools/run_tests) for how to run tests for a given language.
+Use `tools/run_tests/run_tests.py` script to run the unit tests.  See
+[tools/run_tests](tools/run_tests) for how to run tests for a given language.

-Prerequisites for building and running tests are listed in [INSTALL.md](INSTALL.md)
-and in `src/YOUR-LANGUAGE` (e.g. `src/csharp`)
+Prerequisites for building and running tests are listed in
+[INSTALL.md](INSTALL.md) and in `src/YOUR-LANGUAGE` (e.g. `src/csharp`)

 ## Generated project files

-To ease maintenance of language- and platform- specific build systems,
-many projects files are generated using templates and should not be edited
-by hand.
-Run `tools/buildgen/generate_projects.sh` to regenerate.
-See [templates](templates) for details.
+To ease maintenance of language- and platform- specific build systems, many
+projects files are generated using templates and should not be edited by hand.
+Run `tools/buildgen/generate_projects.sh` to regenerate.  See
+[templates](templates) for details.

-As a rule of thumb, if you see the "sanity tests" failing you've most likely edited generated files or you didn't regenerate the projects properly (or your code formatting doesn't match our code style).
+As a rule of thumb, if you see the "sanity tests" failing you've most likely
+edited generated files or you didn't regenerate the projects properly (or your
+code formatting doesn't match our code style).

 ## Guidelines for Pull Requests
 How to get your contributions merged smoothly and quickly.
 
- Create **small PRs** that are narrowly focused on **addressing a single concern**. We often times receive PRs that are trying to fix several things at a time, but only one fix is considered acceptable, nothing gets merged and both author's & review's time is wasted. Create more PRs to address different concerns and everyone will be happy.
+- Create **small PRs** that are narrowly focused on **addressing a single
+  concern**.  We often times receive PRs that are trying to fix several things
+  at a time, but only one fix is considered acceptable, nothing gets merged and
+  both author's & review's time is wasted.  Create more PRs to address different
+  concerns and everyone will be happy.
 
- For speculative changes, consider opening an issue and discussing it first. If you are suggesting a behavioral or API change, consider starting with a [gRFC proposal](https://github.com/grpc/proposal). 
+- For speculative changes, consider opening an issue and discussing it first.
+  If you are suggesting a behavioral or API change, consider starting with a
+  [gRFC proposal](https://github.com/grpc/proposal).
 
- Provide a good **PR description** as a record of **what** change is being made and **why** it was made. Link to a github issue if it exists.
+- Provide a good **PR description** as a record of **what** change is being made
+  and **why** it was made.  Link to a GitHub issue if it exists.
 
- Don't fix code style and formatting unless you are already changing that line to address an issue. PRs with irrelevant changes won't be merged. If you do want to fix formatting or style, do that in a separate PR.
+- Don't fix code style and formatting unless you are already changing that line
+  to address an issue.  PRs with irrelevant changes won't be merged.  If you do
+  want to fix formatting or style, do that in a separate PR.
 
- Unless your PR is trivial, you should expect there will be reviewer comments that you'll need to address before merging. We expect you to be reasonably responsive to those comments, otherwise the PR will be closed after 2-3 weeks of inactivity.
+- Unless your PR is trivial, you should expect there will be reviewer comments
+  that you'll need to address before merging.  We expect you to be reasonably
+  responsive to those comments, otherwise the PR will be closed after 2-3 weeks
+  of inactivity.
+
+- If you have non-trivial contributions, please consider adding an entry to [the
+  AUTHORS file](https://github.com/grpc/grpc/blob/master/AUTHORS) listing the
+  copyright holder for the contribution (yourself, if you are signing the
+  individual CLA, or your company, for corporate CLAs) in the same PR as your
+  contribution.  This needs to be done only once, for each company, or
+  individual.
 
- Maintain **clean commit history** and use **meaningful commit messages**. PRs with messy commit history are difficult to review and won't be merged. Use `rebase -i upstream/master` to curate your commit history and/or to bring in latest changes from master (but avoid rebasing in the middle of a code review).
+- Maintain **clean commit history** and use **meaningful commit messages**.
+  PRs with messy commit history are difficult to review and won't be merged.
+  Use `rebase -i upstream/master` to curate your commit history and/or to
+  bring in latest changes from master (but avoid rebasing in the middle of
+  a code review).
 
- Keep your PR up to date with upstream/master (if there are merge conflicts, we can't really merge your change).
+- Keep your PR up to date with upstream/master (if there are merge conflicts,
+  we can't really merge your change).
 
- if you are regenerating the projects using `tools/buildgen/generate_projects.sh`, make changes to generated files a separate commit with commit message `regenerate projects`. Mixing changes to generated and hand-written files make your PR difficult to review.
+- If you are regenerating the projects using
+  `tools/buildgen/generate_projects.sh`, make changes to generated files a
+  separate commit with commit message `regenerate projects`.  Mixing changes
+  to generated and hand-written files make your PR difficult to review.
+  Note that running this script requires the installation of Python packages
+  `pyyaml` and `mako` (typically installed using `pip`) as well as a recent
+  version of [`go`](https://golang.org/doc/install#install).
 
- **All tests need to be passing** before your change can be merged. We recommend you **run tests locally** before creating your PR to catch breakages early on (see [tools/run_tests](tools/run_tests). Ultimately, the green signal will be provided by our testing infrastructure. The reviewer will help you if there are test failures that seem not related to the change you are making.
+- **All tests need to be passing** before your change can be merged.
+  We recommend you **run tests locally** before creating your PR to catch
+  breakages early on (see [tools/run_tests](tools/run_tests).  Ultimately, the
+  green signal will be provided by our testing infrastructure.  The reviewer
+  will help you if there are test failures that seem not related to the change
+  you are making.
 
- Exceptions to the rules can be made if there's a compelling reason for doing so.
+- Exceptions to the rules can be made if there's a compelling reason for doing
+  so.



--- a/361
+++ b/361
@ -77,7 +77,6 @@ CC_opt = $(DEFAULT_CC)
 CXX_opt = $(DEFAULT_CXX)
 LD_opt = $(DEFAULT_CC)
 LDXX_opt = $(DEFAULT_CXX)
-CXXFLAGS_opt = -fno-exceptions
 CPPFLAGS_opt = -O2
 DEFINES_opt = NDEBUG

@ -95,7 +94,6 @@ CC_dbg = $(DEFAULT_CC)
 CXX_dbg = $(DEFAULT_CXX)
 LD_dbg = $(DEFAULT_CC)
 LDXX_dbg = $(DEFAULT_CXX)
-CXXFLAGS_dbg = -fno-exceptions
 CPPFLAGS_dbg = -O0
 DEFINES_dbg = _DEBUG DEBUG

@ -144,14 +142,14 @@ LDXX_asan-noleaks = clang++
 CPPFLAGS_asan-noleaks = -O0 -fsanitize-coverage=edge -fsanitize=address -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
 LDFLAGS_asan-noleaks = -fsanitize=address

-VALID_CONFIG_c++-compat = 1
-CC_c++-compat = $(DEFAULT_CC)
-CXX_c++-compat = $(DEFAULT_CXX)
-LD_c++-compat = $(DEFAULT_CC)
-LDXX_c++-compat = $(DEFAULT_CXX)
-CFLAGS_c++-compat = -Wc++-compat
-CPPFLAGS_c++-compat = -O0
-DEFINES_c++-compat = _DEBUG DEBUG
+VALID_CONFIG_noexcept = 1
+CC_noexcept = $(DEFAULT_CC)
+CXX_noexcept = $(DEFAULT_CXX)
+LD_noexcept = $(DEFAULT_CC)
+LDXX_noexcept = $(DEFAULT_CXX)
+CXXFLAGS_noexcept = -fno-exceptions
+CPPFLAGS_noexcept = -O2
+DEFINES_noexcept = NDEBUG

 VALID_CONFIG_ubsan = 1
 REQUIRE_CUSTOM_LIBRARIES_ubsan = 1
@ -207,6 +205,15 @@ LDXX_lto = $(DEFAULT_CXX)
 CPPFLAGS_lto = -O2
 DEFINES_lto = NDEBUG

+VALID_CONFIG_c++-compat = 1
+CC_c++-compat = $(DEFAULT_CC)
+CXX_c++-compat = $(DEFAULT_CXX)
+LD_c++-compat = $(DEFAULT_CC)
+LDXX_c++-compat = $(DEFAULT_CXX)
+CFLAGS_c++-compat = -Wc++-compat
+CPPFLAGS_c++-compat = -O0
+DEFINES_c++-compat = _DEBUG DEBUG
+
 VALID_CONFIG_mutrace = 1
 CC_mutrace = $(DEFAULT_CC)
 CXX_mutrace = $(DEFAULT_CXX)
@ -327,7 +334,7 @@ CXXFLAGS += -std=c++11
 ifeq ($(SYSTEM),Darwin)
 CXXFLAGS += -stdlib=libc++
 endif
-CPPFLAGS += -g -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter -DOSATOMIC_USE_INLINED=1
+CPPFLAGS += -g -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter -DOSATOMIC_USE_INLINED=1 -Wno-deprecated-declarations
 COREFLAGS += -fno-rtti -fno-exceptions
 LDFLAGS += -g

@ -412,8 +419,8 @@ Q = @
 endif

 CORE_VERSION = 5.0.0-dev
-CPP_VERSION = 1.9.0-dev
-CSHARP_VERSION = 1.9.0-dev
+CPP_VERSION = 1.10.0-dev
+CSHARP_VERSION = 1.10.0-dev

 CPPFLAGS_NO_ARCH += $(addprefix -I, $(INCLUDES)) $(addprefix -D, $(DEFINES))
 CPPFLAGS += $(CPPFLAGS_NO_ARCH) $(ARCH_FLAGS)
@ -643,7 +650,6 @@ ZLIB_DEP = $(LIBDIR)/$(CONFIG)/libz.a
 ZLIB_MERGE_LIBS = $(LIBDIR)/$(CONFIG)/libz.a
 ZLIB_MERGE_OBJS = $(LIBZ_OBJS)
 CPPFLAGS += -Ithird_party/zlib
-LDFLAGS += -L$(LIBDIR)/$(CONFIG)/zlib
 else
 ifeq ($(HAS_PKG_CONFIG),true)
 CPPFLAGS += $(shell $(PKG_CONFIG) --cflags zlib)
@ -674,7 +680,6 @@ CARES_DEP = $(LIBDIR)/$(CONFIG)/libares.a
 CARES_MERGE_OBJS = $(LIBARES_OBJS)
 CARES_MERGE_LIBS = $(LIBDIR)/$(CONFIG)/libares.a
 CPPFLAGS := -Ithird_party/cares -Ithird_party/cares/cares $(CPPFLAGS)
-LDFLAGS := -L$(LIBDIR)/$(CONFIG)/c-ares $(LDFLAGS)
 else
 ifeq ($(HAS_PKG_CONFIG),true)
 PC_REQUIRES_GRPC += libcares
@ -1126,6 +1131,7 @@ cxx_string_ref_test: $(BINDIR)/$(CONFIG)/cxx_string_ref_test
 cxx_time_test: $(BINDIR)/$(CONFIG)/cxx_time_test
 end2end_test: $(BINDIR)/$(CONFIG)/end2end_test
 error_details_test: $(BINDIR)/$(CONFIG)/error_details_test
+exception_test: $(BINDIR)/$(CONFIG)/exception_test
 filter_end2end_test: $(BINDIR)/$(CONFIG)/filter_end2end_test
 generic_end2end_test: $(BINDIR)/$(CONFIG)/generic_end2end_test
 golden_file_test: $(BINDIR)/$(CONFIG)/golden_file_test
@ -1145,6 +1151,7 @@ h2_ssl_cert_test: $(BINDIR)/$(CONFIG)/h2_ssl_cert_test
 health_service_end2end_test: $(BINDIR)/$(CONFIG)/health_service_end2end_test
 http2_client: $(BINDIR)/$(CONFIG)/http2_client
 hybrid_end2end_test: $(BINDIR)/$(CONFIG)/hybrid_end2end_test
+inlined_vector_test: $(BINDIR)/$(CONFIG)/inlined_vector_test
 inproc_sync_unary_ping_pong_test: $(BINDIR)/$(CONFIG)/inproc_sync_unary_ping_pong_test
 interop_client: $(BINDIR)/$(CONFIG)/interop_client
 interop_server: $(BINDIR)/$(CONFIG)/interop_server
@ -1154,6 +1161,7 @@ memory_test: $(BINDIR)/$(CONFIG)/memory_test
 metrics_client: $(BINDIR)/$(CONFIG)/metrics_client
 mock_test: $(BINDIR)/$(CONFIG)/mock_test
 noop-benchmark: $(BINDIR)/$(CONFIG)/noop-benchmark
+orphanable_test: $(BINDIR)/$(CONFIG)/orphanable_test
 proto_server_reflection_test: $(BINDIR)/$(CONFIG)/proto_server_reflection_test
 proto_utils_test: $(BINDIR)/$(CONFIG)/proto_utils_test
 qps_interarrival_test: $(BINDIR)/$(CONFIG)/qps_interarrival_test
@ -1301,10 +1309,10 @@ third_party/protobuf/configure:

 $(LIBDIR)/$(CONFIG)/protobuf/libprotobuf.a: third_party/protobuf/configure
 	$(E) "[MAKE]    Building protobuf"
+	$(Q)mkdir -p $(LIBDIR)/$(CONFIG)/protobuf
 	$(Q)(cd third_party/protobuf ; CC="$(CC)" CXX="$(CXX)" LDFLAGS="$(LDFLAGS_$(CONFIG)) -g $(PROTOBUF_LDFLAGS_EXTRA)" CPPFLAGS="$(PIC_CPPFLAGS) $(CPPFLAGS_$(CONFIG)) -g $(PROTOBUF_CPPFLAGS_EXTRA)" ./configure --disable-shared --enable-static $(PROTOBUF_CONFIG_OPTS))
 	$(Q)$(MAKE) -C third_party/protobuf clean
 	$(Q)$(MAKE) -C third_party/protobuf
-	$(Q)mkdir -p $(LIBDIR)/$(CONFIG)/protobuf
 	$(Q)mkdir -p $(BINDIR)/$(CONFIG)/protobuf
 	$(Q)cp third_party/protobuf/src/.libs/libprotoc.a $(LIBDIR)/$(CONFIG)/protobuf
 	$(Q)cp third_party/protobuf/src/.libs/libprotobuf.a $(LIBDIR)/$(CONFIG)/protobuf
@ -1573,6 +1581,7 @@ buildtests_cxx: privatelibs_cxx \
  $(BINDIR)/$(CONFIG)/cxx_time_test \
  $(BINDIR)/$(CONFIG)/end2end_test \
  $(BINDIR)/$(CONFIG)/error_details_test \
+  $(BINDIR)/$(CONFIG)/exception_test \
  $(BINDIR)/$(CONFIG)/filter_end2end_test \
  $(BINDIR)/$(CONFIG)/generic_end2end_test \
  $(BINDIR)/$(CONFIG)/golden_file_test \
@ -1585,6 +1594,7 @@ buildtests_cxx: privatelibs_cxx \
  $(BINDIR)/$(CONFIG)/health_service_end2end_test \
  $(BINDIR)/$(CONFIG)/http2_client \
  $(BINDIR)/$(CONFIG)/hybrid_end2end_test \
+  $(BINDIR)/$(CONFIG)/inlined_vector_test \
  $(BINDIR)/$(CONFIG)/inproc_sync_unary_ping_pong_test \
  $(BINDIR)/$(CONFIG)/interop_client \
  $(BINDIR)/$(CONFIG)/interop_server \
@ -1594,6 +1604,7 @@ buildtests_cxx: privatelibs_cxx \
  $(BINDIR)/$(CONFIG)/metrics_client \
  $(BINDIR)/$(CONFIG)/mock_test \
  $(BINDIR)/$(CONFIG)/noop-benchmark \
+  $(BINDIR)/$(CONFIG)/orphanable_test \
  $(BINDIR)/$(CONFIG)/proto_server_reflection_test \
  $(BINDIR)/$(CONFIG)/proto_utils_test \
  $(BINDIR)/$(CONFIG)/qps_interarrival_test \
@ -1702,6 +1713,7 @@ buildtests_cxx: privatelibs_cxx \
  $(BINDIR)/$(CONFIG)/cxx_time_test \
  $(BINDIR)/$(CONFIG)/end2end_test \
  $(BINDIR)/$(CONFIG)/error_details_test \
+  $(BINDIR)/$(CONFIG)/exception_test \
  $(BINDIR)/$(CONFIG)/filter_end2end_test \
  $(BINDIR)/$(CONFIG)/generic_end2end_test \
  $(BINDIR)/$(CONFIG)/golden_file_test \
@ -1714,6 +1726,7 @@ buildtests_cxx: privatelibs_cxx \
  $(BINDIR)/$(CONFIG)/health_service_end2end_test \
  $(BINDIR)/$(CONFIG)/http2_client \
  $(BINDIR)/$(CONFIG)/hybrid_end2end_test \
+  $(BINDIR)/$(CONFIG)/inlined_vector_test \
  $(BINDIR)/$(CONFIG)/inproc_sync_unary_ping_pong_test \
  $(BINDIR)/$(CONFIG)/interop_client \
  $(BINDIR)/$(CONFIG)/interop_server \
@ -1723,6 +1736,7 @@ buildtests_cxx: privatelibs_cxx \
  $(BINDIR)/$(CONFIG)/metrics_client \
  $(BINDIR)/$(CONFIG)/mock_test \
  $(BINDIR)/$(CONFIG)/noop-benchmark \
+  $(BINDIR)/$(CONFIG)/orphanable_test \
  $(BINDIR)/$(CONFIG)/proto_server_reflection_test \
  $(BINDIR)/$(CONFIG)/proto_utils_test \
  $(BINDIR)/$(CONFIG)/qps_interarrival_test \
@ -2101,6 +2115,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/end2end_test || ( echo test end2end_test failed ; exit 1 )
 	$(E) "[RUN]     Testing error_details_test"
 	$(Q) $(BINDIR)/$(CONFIG)/error_details_test || ( echo test error_details_test failed ; exit 1 )
+	$(E) "[RUN]     Testing exception_test"
+	$(Q) $(BINDIR)/$(CONFIG)/exception_test || ( echo test exception_test failed ; exit 1 )
 	$(E) "[RUN]     Testing filter_end2end_test"
 	$(Q) $(BINDIR)/$(CONFIG)/filter_end2end_test || ( echo test filter_end2end_test failed ; exit 1 )
 	$(E) "[RUN]     Testing generic_end2end_test"
@ -2119,6 +2135,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/h2_ssl_cert_test || ( echo test h2_ssl_cert_test failed ; exit 1 )
 	$(E) "[RUN]     Testing health_service_end2end_test"
 	$(Q) $(BINDIR)/$(CONFIG)/health_service_end2end_test || ( echo test health_service_end2end_test failed ; exit 1 )
+	$(E) "[RUN]     Testing inlined_vector_test"
+	$(Q) $(BINDIR)/$(CONFIG)/inlined_vector_test || ( echo test inlined_vector_test failed ; exit 1 )
 	$(E) "[RUN]     Testing inproc_sync_unary_ping_pong_test"
 	$(Q) $(BINDIR)/$(CONFIG)/inproc_sync_unary_ping_pong_test || ( echo test inproc_sync_unary_ping_pong_test failed ; exit 1 )
 	$(E) "[RUN]     Testing interop_test"
@ -2129,6 +2147,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/mock_test || ( echo test mock_test failed ; exit 1 )
 	$(E) "[RUN]     Testing noop-benchmark"
 	$(Q) $(BINDIR)/$(CONFIG)/noop-benchmark || ( echo test noop-benchmark failed ; exit 1 )
+	$(E) "[RUN]     Testing orphanable_test"
+	$(Q) $(BINDIR)/$(CONFIG)/orphanable_test || ( echo test orphanable_test failed ; exit 1 )
 	$(E) "[RUN]     Testing proto_server_reflection_test"
 	$(Q) $(BINDIR)/$(CONFIG)/proto_server_reflection_test || ( echo test proto_server_reflection_test failed ; exit 1 )
 	$(E) "[RUN]     Testing proto_utils_test"
@ -2820,50 +2840,50 @@ clean:


 LIBGPR_SRC = \
+    src/core/lib/gpr/alloc.cc \
+    src/core/lib/gpr/arena.cc \
+    src/core/lib/gpr/atm.cc \
+    src/core/lib/gpr/avl.cc \
+    src/core/lib/gpr/cmdline.cc \
+    src/core/lib/gpr/cpu_iphone.cc \
+    src/core/lib/gpr/cpu_linux.cc \
+    src/core/lib/gpr/cpu_posix.cc \
+    src/core/lib/gpr/cpu_windows.cc \
+    src/core/lib/gpr/env_linux.cc \
+    src/core/lib/gpr/env_posix.cc \
+    src/core/lib/gpr/env_windows.cc \
+    src/core/lib/gpr/fork.cc \
+    src/core/lib/gpr/host_port.cc \
+    src/core/lib/gpr/log.cc \
+    src/core/lib/gpr/log_android.cc \
+    src/core/lib/gpr/log_linux.cc \
+    src/core/lib/gpr/log_posix.cc \
+    src/core/lib/gpr/log_windows.cc \
+    src/core/lib/gpr/mpscq.cc \
+    src/core/lib/gpr/murmur_hash.cc \
+    src/core/lib/gpr/string.cc \
+    src/core/lib/gpr/string_posix.cc \
+    src/core/lib/gpr/string_util_windows.cc \
+    src/core/lib/gpr/string_windows.cc \
+    src/core/lib/gpr/subprocess_posix.cc \
+    src/core/lib/gpr/subprocess_windows.cc \
+    src/core/lib/gpr/sync.cc \
+    src/core/lib/gpr/sync_posix.cc \
+    src/core/lib/gpr/sync_windows.cc \
+    src/core/lib/gpr/thd.cc \
+    src/core/lib/gpr/thd_posix.cc \
+    src/core/lib/gpr/thd_windows.cc \
+    src/core/lib/gpr/time.cc \
+    src/core/lib/gpr/time_posix.cc \
+    src/core/lib/gpr/time_precise.cc \
+    src/core/lib/gpr/time_windows.cc \
+    src/core/lib/gpr/tls_pthread.cc \
+    src/core/lib/gpr/tmpfile_msys.cc \
+    src/core/lib/gpr/tmpfile_posix.cc \
+    src/core/lib/gpr/tmpfile_windows.cc \
+    src/core/lib/gpr/wrap_memcpy.cc \
    src/core/lib/profiling/basic_timers.cc \
    src/core/lib/profiling/stap_timers.cc \
-    src/core/lib/support/alloc.cc \
-    src/core/lib/support/arena.cc \
-    src/core/lib/support/atm.cc \
-    src/core/lib/support/avl.cc \
-    src/core/lib/support/cmdline.cc \
-    src/core/lib/support/cpu_iphone.cc \
-    src/core/lib/support/cpu_linux.cc \
-    src/core/lib/support/cpu_posix.cc \
-    src/core/lib/support/cpu_windows.cc \
-    src/core/lib/support/env_linux.cc \
-    src/core/lib/support/env_posix.cc \
-    src/core/lib/support/env_windows.cc \
-    src/core/lib/support/fork.cc \
-    src/core/lib/support/host_port.cc \
-    src/core/lib/support/log.cc \
-    src/core/lib/support/log_android.cc \
-    src/core/lib/support/log_linux.cc \
-    src/core/lib/support/log_posix.cc \
-    src/core/lib/support/log_windows.cc \
-    src/core/lib/support/mpscq.cc \
-    src/core/lib/support/murmur_hash.cc \
-    src/core/lib/support/string.cc \
-    src/core/lib/support/string_posix.cc \
-    src/core/lib/support/string_util_windows.cc \
-    src/core/lib/support/string_windows.cc \
-    src/core/lib/support/subprocess_posix.cc \
-    src/core/lib/support/subprocess_windows.cc \
-    src/core/lib/support/sync.cc \
-    src/core/lib/support/sync_posix.cc \
-    src/core/lib/support/sync_windows.cc \
-    src/core/lib/support/thd.cc \
-    src/core/lib/support/thd_posix.cc \
-    src/core/lib/support/thd_windows.cc \
-    src/core/lib/support/time.cc \
-    src/core/lib/support/time_posix.cc \
-    src/core/lib/support/time_precise.cc \
-    src/core/lib/support/time_windows.cc \
-    src/core/lib/support/tls_pthread.cc \
-    src/core/lib/support/tmpfile_msys.cc \
-    src/core/lib/support/tmpfile_posix.cc \
-    src/core/lib/support/tmpfile_windows.cc \
-    src/core/lib/support/wrap_memcpy.cc \

 PUBLIC_HEADERS_C += \
    include/grpc/support/alloc.h \
@ -3226,7 +3246,6 @@ PUBLIC_HEADERS_C += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -3540,7 +3559,6 @@ PUBLIC_HEADERS_C += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -3827,7 +3845,6 @@ PUBLIC_HEADERS_C += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -4088,7 +4105,6 @@ PUBLIC_HEADERS_C += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -4354,7 +4370,6 @@ PUBLIC_HEADERS_C += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -4646,7 +4661,6 @@ PUBLIC_HEADERS_CXX += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -5133,7 +5147,6 @@ PUBLIC_HEADERS_CXX += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -5526,7 +5539,6 @@ PUBLIC_HEADERS_CXX += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -5644,7 +5656,6 @@ PUBLIC_HEADERS_CXX += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -5854,7 +5865,6 @@ PUBLIC_HEADERS_CXX += \
    include/grpc/impl/codegen/byte_buffer_reader.h \
    include/grpc/impl/codegen/compression_types.h \
    include/grpc/impl/codegen/connectivity_state.h \
-    include/grpc/impl/codegen/exec_ctx_fwd.h \
    include/grpc/impl/codegen/grpc_types.h \
    include/grpc/impl/codegen/propagation_bits.h \
    include/grpc/impl/codegen/slice.h \
@ -8557,6 +8567,7 @@ LIBEND2END_TESTS_SRC = \
    test/core/end2end/tests/filter_call_init_fails.cc \
    test/core/end2end/tests/filter_causes_close.cc \
    test/core/end2end/tests/filter_latency.cc \
+    test/core/end2end/tests/filter_status_code.cc \
    test/core/end2end/tests/graceful_server_shutdown.cc \
    test/core/end2end/tests/high_initial_seqno.cc \
    test/core/end2end/tests/hpack_size.cc \
@ -8655,6 +8666,7 @@ LIBEND2END_NOSEC_TESTS_SRC = \
    test/core/end2end/tests/filter_call_init_fails.cc \
    test/core/end2end/tests/filter_causes_close.cc \
    test/core/end2end/tests/filter_latency.cc \
+    test/core/end2end/tests/filter_status_code.cc \
    test/core/end2end/tests/graceful_server_shutdown.cc \
    test/core/end2end/tests/high_initial_seqno.cc \
    test/core/end2end/tests/hpack_size.cc \
@ -8786,7 +8798,7 @@ endif


 ALLOC_TEST_SRC = \
-    test/core/support/alloc_test.cc \
+    test/core/gpr/alloc_test.cc \

 ALLOC_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(ALLOC_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -8806,7 +8818,7 @@ $(BINDIR)/$(CONFIG)/alloc_test: $(ALLOC_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgpr_te

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/alloc_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/alloc_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_alloc_test: $(ALLOC_TEST_OBJS:.o=.dep)

@ -8882,7 +8894,7 @@ endif


 ARENA_TEST_SRC = \
-    test/core/support/arena_test.cc \
+    test/core/gpr/arena_test.cc \

 ARENA_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(ARENA_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -8902,7 +8914,7 @@ $(BINDIR)/$(CONFIG)/arena_test: $(ARENA_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgpr_te

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/arena_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/arena_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_arena_test: $(ARENA_TEST_OBJS:.o=.dep)

@ -9845,7 +9857,7 @@ endif


 GPR_AVL_TEST_SRC = \
-    test/core/support/avl_test.cc \
+    test/core/gpr/avl_test.cc \

 GPR_AVL_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_AVL_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -9865,7 +9877,7 @@ $(BINDIR)/$(CONFIG)/gpr_avl_test: $(GPR_AVL_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgp

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/avl_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/avl_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_avl_test: $(GPR_AVL_TEST_OBJS:.o=.dep)

@ -9877,7 +9889,7 @@ endif


 GPR_CMDLINE_TEST_SRC = \
-    test/core/support/cmdline_test.cc \
+    test/core/gpr/cmdline_test.cc \

 GPR_CMDLINE_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_CMDLINE_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -9897,7 +9909,7 @@ $(BINDIR)/$(CONFIG)/gpr_cmdline_test: $(GPR_CMDLINE_TEST_OBJS) $(LIBDIR)/$(CONFI

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/cmdline_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/cmdline_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_cmdline_test: $(GPR_CMDLINE_TEST_OBJS:.o=.dep)

@ -9909,7 +9921,7 @@ endif


 GPR_CPU_TEST_SRC = \
-    test/core/support/cpu_test.cc \
+    test/core/gpr/cpu_test.cc \

 GPR_CPU_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_CPU_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -9929,7 +9941,7 @@ $(BINDIR)/$(CONFIG)/gpr_cpu_test: $(GPR_CPU_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgp

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/cpu_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/cpu_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_cpu_test: $(GPR_CPU_TEST_OBJS:.o=.dep)

@ -9941,7 +9953,7 @@ endif


 GPR_ENV_TEST_SRC = \
-    test/core/support/env_test.cc \
+    test/core/gpr/env_test.cc \

 GPR_ENV_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_ENV_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -9961,7 +9973,7 @@ $(BINDIR)/$(CONFIG)/gpr_env_test: $(GPR_ENV_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgp

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/env_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/env_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_env_test: $(GPR_ENV_TEST_OBJS:.o=.dep)

@ -9973,7 +9985,7 @@ endif


 GPR_HOST_PORT_TEST_SRC = \
-    test/core/support/host_port_test.cc \
+    test/core/gpr/host_port_test.cc \

 GPR_HOST_PORT_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_HOST_PORT_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -9993,7 +10005,7 @@ $(BINDIR)/$(CONFIG)/gpr_host_port_test: $(GPR_HOST_PORT_TEST_OBJS) $(LIBDIR)/$(C

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/host_port_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/host_port_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_host_port_test: $(GPR_HOST_PORT_TEST_OBJS:.o=.dep)

@ -10005,7 +10017,7 @@ endif


 GPR_LOG_TEST_SRC = \
-    test/core/support/log_test.cc \
+    test/core/gpr/log_test.cc \

 GPR_LOG_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_LOG_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10025,7 +10037,7 @@ $(BINDIR)/$(CONFIG)/gpr_log_test: $(GPR_LOG_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgp

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/log_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/log_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_log_test: $(GPR_LOG_TEST_OBJS:.o=.dep)

@ -10037,7 +10049,7 @@ endif


 GPR_MANUAL_CONSTRUCTOR_TEST_SRC = \
-    test/core/support/manual_constructor_test.cc \
+    test/core/gprpp/manual_constructor_test.cc \

 GPR_MANUAL_CONSTRUCTOR_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_MANUAL_CONSTRUCTOR_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10057,7 +10069,7 @@ $(BINDIR)/$(CONFIG)/gpr_manual_constructor_test: $(GPR_MANUAL_CONSTRUCTOR_TEST_O

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/manual_constructor_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gprpp/manual_constructor_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_manual_constructor_test: $(GPR_MANUAL_CONSTRUCTOR_TEST_OBJS:.o=.dep)

@ -10069,7 +10081,7 @@ endif


 GPR_MPSCQ_TEST_SRC = \
-    test/core/support/mpscq_test.cc \
+    test/core/gpr/mpscq_test.cc \

 GPR_MPSCQ_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_MPSCQ_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10089,7 +10101,7 @@ $(BINDIR)/$(CONFIG)/gpr_mpscq_test: $(GPR_MPSCQ_TEST_OBJS) $(LIBDIR)/$(CONFIG)/l

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/mpscq_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/mpscq_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_mpscq_test: $(GPR_MPSCQ_TEST_OBJS:.o=.dep)

@ -10101,7 +10113,7 @@ endif


 GPR_SPINLOCK_TEST_SRC = \
-    test/core/support/spinlock_test.cc \
+    test/core/gpr/spinlock_test.cc \

 GPR_SPINLOCK_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_SPINLOCK_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10121,7 +10133,7 @@ $(BINDIR)/$(CONFIG)/gpr_spinlock_test: $(GPR_SPINLOCK_TEST_OBJS) $(LIBDIR)/$(CON

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/spinlock_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/spinlock_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_spinlock_test: $(GPR_SPINLOCK_TEST_OBJS:.o=.dep)

@ -10133,7 +10145,7 @@ endif


 GPR_STRING_TEST_SRC = \
-    test/core/support/string_test.cc \
+    test/core/gpr/string_test.cc \

 GPR_STRING_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_STRING_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10153,7 +10165,7 @@ $(BINDIR)/$(CONFIG)/gpr_string_test: $(GPR_STRING_TEST_OBJS) $(LIBDIR)/$(CONFIG)

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/string_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/string_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_string_test: $(GPR_STRING_TEST_OBJS:.o=.dep)

@ -10165,7 +10177,7 @@ endif


 GPR_SYNC_TEST_SRC = \
-    test/core/support/sync_test.cc \
+    test/core/gpr/sync_test.cc \

 GPR_SYNC_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_SYNC_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10185,7 +10197,7 @@ $(BINDIR)/$(CONFIG)/gpr_sync_test: $(GPR_SYNC_TEST_OBJS) $(LIBDIR)/$(CONFIG)/lib

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/sync_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/sync_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_sync_test: $(GPR_SYNC_TEST_OBJS:.o=.dep)

@ -10197,7 +10209,7 @@ endif


 GPR_THD_TEST_SRC = \
-    test/core/support/thd_test.cc \
+    test/core/gpr/thd_test.cc \

 GPR_THD_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_THD_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10217,7 +10229,7 @@ $(BINDIR)/$(CONFIG)/gpr_thd_test: $(GPR_THD_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgp

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/thd_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/thd_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_thd_test: $(GPR_THD_TEST_OBJS:.o=.dep)

@ -10229,7 +10241,7 @@ endif


 GPR_TIME_TEST_SRC = \
-    test/core/support/time_test.cc \
+    test/core/gpr/time_test.cc \

 GPR_TIME_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_TIME_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10249,7 +10261,7 @@ $(BINDIR)/$(CONFIG)/gpr_time_test: $(GPR_TIME_TEST_OBJS) $(LIBDIR)/$(CONFIG)/lib

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/time_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/time_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_time_test: $(GPR_TIME_TEST_OBJS:.o=.dep)

@ -10261,7 +10273,7 @@ endif


 GPR_TLS_TEST_SRC = \
-    test/core/support/tls_test.cc \
+    test/core/gpr/tls_test.cc \

 GPR_TLS_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_TLS_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10281,7 +10293,7 @@ $(BINDIR)/$(CONFIG)/gpr_tls_test: $(GPR_TLS_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgp

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/tls_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/tls_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_tls_test: $(GPR_TLS_TEST_OBJS:.o=.dep)

@ -10293,7 +10305,7 @@ endif


 GPR_USEFUL_TEST_SRC = \
-    test/core/support/useful_test.cc \
+    test/core/gpr/useful_test.cc \

 GPR_USEFUL_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_USEFUL_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -10313,7 +10325,7 @@ $(BINDIR)/$(CONFIG)/gpr_useful_test: $(GPR_USEFUL_TEST_OBJS) $(LIBDIR)/$(CONFIG)

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/useful_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/useful_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_gpr_useful_test: $(GPR_USEFUL_TEST_OBJS:.o=.dep)

@ -11867,7 +11879,7 @@ endif


 MURMUR_HASH_TEST_SRC = \
-    test/core/support/murmur_hash_test.cc \
+    test/core/gpr/murmur_hash_test.cc \

 MURMUR_HASH_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(MURMUR_HASH_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -11887,7 +11899,7 @@ $(BINDIR)/$(CONFIG)/murmur_hash_test: $(MURMUR_HASH_TEST_OBJS) $(LIBDIR)/$(CONFI

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/murmur_hash_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gpr/murmur_hash_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_murmur_hash_test: $(MURMUR_HASH_TEST_OBJS:.o=.dep)

@ -14979,6 +14991,49 @@ endif
 $(OBJDIR)/$(CONFIG)/test/cpp/util/error_details_test.o: $(GENDIR)/src/proto/grpc/testing/echo_messages.pb.cc $(GENDIR)/src/proto/grpc/testing/echo_messages.grpc.pb.cc


+EXCEPTION_TEST_SRC = \
+    test/cpp/end2end/exception_test.cc \
+
+EXCEPTION_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(EXCEPTION_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/exception_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/exception_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/exception_test: $(PROTOBUF_DEP) $(EXCEPTION_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(EXCEPTION_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/exception_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/end2end/exception_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_exception_test: $(EXCEPTION_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(EXCEPTION_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 FILTER_END2END_TEST_SRC = \
    test/cpp/end2end/filter_end2end_test.cc \

@ -15723,6 +15778,49 @@ endif
 endif


+INLINED_VECTOR_TEST_SRC = \
+    test/core/gprpp/inlined_vector_test.cc \
+
+INLINED_VECTOR_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(INLINED_VECTOR_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/inlined_vector_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/inlined_vector_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/inlined_vector_test: $(PROTOBUF_DEP) $(INLINED_VECTOR_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(INLINED_VECTOR_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/inlined_vector_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/gprpp/inlined_vector_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_inlined_vector_test: $(INLINED_VECTOR_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(INLINED_VECTOR_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 INPROC_SYNC_UNARY_PING_PONG_TEST_SRC = \
    test/cpp/qps/inproc_sync_unary_ping_pong_test.cc \

@ -15915,7 +16013,7 @@ endif


 MEMORY_TEST_SRC = \
-    test/core/support/memory_test.cc \
+    test/core/gprpp/memory_test.cc \

 MEMORY_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(MEMORY_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -15946,7 +16044,7 @@ endif

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/memory_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gprpp/memory_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_memory_test: $(MEMORY_TEST_OBJS:.o=.dep)

@ -16091,6 +16189,49 @@ endif
 endif


+ORPHANABLE_TEST_SRC = \
+    test/core/gprpp/orphanable_test.cc \
+
+ORPHANABLE_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(ORPHANABLE_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/orphanable_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/orphanable_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/orphanable_test: $(PROTOBUF_DEP) $(ORPHANABLE_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(ORPHANABLE_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/orphanable_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/gprpp/orphanable_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_orphanable_test: $(ORPHANABLE_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(ORPHANABLE_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 PROTO_SERVER_REFLECTION_TEST_SRC = \
    test/cpp/end2end/proto_server_reflection_test.cc \

@ -16456,7 +16597,7 @@ $(OBJDIR)/$(CONFIG)/test/cpp/interop/reconnect_interop_server.o: $(GENDIR)/src/p


 REF_COUNTED_PTR_TEST_SRC = \
-    test/core/support/ref_counted_ptr_test.cc \
+    test/core/gprpp/ref_counted_ptr_test.cc \

 REF_COUNTED_PTR_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(REF_COUNTED_PTR_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -16487,7 +16628,7 @@ endif

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/ref_counted_ptr_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gprpp/ref_counted_ptr_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_ref_counted_ptr_test: $(REF_COUNTED_PTR_TEST_OBJS:.o=.dep)

@ -16499,7 +16640,7 @@ endif


 REF_COUNTED_TEST_SRC = \
-    test/core/support/ref_counted_test.cc \
+    test/core/gprpp/ref_counted_test.cc \

 REF_COUNTED_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(REF_COUNTED_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
@ -16530,7 +16671,7 @@ endif

 endif

-$(OBJDIR)/$(CONFIG)/test/core/support/ref_counted_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(OBJDIR)/$(CONFIG)/test/core/gprpp/ref_counted_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a

 deps_ref_counted_test: $(REF_COUNTED_TEST_OBJS:.o=.dep)

--- a/2
+++ b/2
@ -13,5 +13,5 @@
 #         lead to a bus factor of one to changes to that code
@markdroth **/OWNERS
@nicolasnoble **/OWNERS
-@ctiller **/OWNERS
+@a11r **/OWNERS

--- a/4
+++ b/4
@ -113,10 +113,10 @@ task 'gem:native' do
  if RUBY_PLATFORM =~ /darwin/
    FileUtils.touch 'grpc_c.32.ruby'
    FileUtils.touch 'grpc_c.64.ruby'
-    system "rake cross native gem RUBY_CC_VERSION=2.4.0:2.3.0:2.2.2:2.1.5:2.0.0 V=#{verbose} GRPC_CONFIG=#{grpc_config}"
+    system "rake cross native gem RUBY_CC_VERSION=2.5.0:2.4.0:2.3.0:2.2.2:2.1.6:2.0.0 V=#{verbose} GRPC_CONFIG=#{grpc_config}"
  else
    Rake::Task['dlls'].execute
-    docker_for_windows "gem update --system && bundle && rake cross native gem RUBY_CC_VERSION=2.4.0:2.3.0:2.2.2:2.1.5:2.0.0 V=#{verbose} GRPC_CONFIG=#{grpc_config}"
+    docker_for_windows "gem update --system && bundle && rake cross native gem RUBY_CC_VERSION=2.5.0:2.4.0:2.3.0:2.2.2:2.1.6:2.0.0 V=#{verbose} GRPC_CONFIG=#{grpc_config}"
  end
 end

--- a/bazel/OWNERS
+++ b/bazel/OWNERS
@ -1,5 +1,6 @@
 set noparent
@nicolasnoble
@dgquintas
-@ctiller
+@a11r
+@vjpai

--- a/bazel/grpc_build_system.bzl
+++ b/bazel/grpc_build_system.bzl
@ -30,9 +30,12 @@ def _get_external_deps(external_deps):
  ret = []
  for dep in external_deps:
    if dep == "nanopb":
-      ret.append("//third_party/nanopb")
+      ret += ["//third_party/nanopb"]
+    elif dep == "cares":
+      ret += select({"//:grpc_no_ares": [],
+                     "//conditions:default": ["//external:cares"],})
    else:
-      ret.append("//external:" + dep)
+      ret += ["//external:" + dep]
  return ret

 def _maybe_update_cc_library_hdrs(hdrs):
@ -60,6 +63,10 @@ def grpc_cc_library(name, srcs = [], public_hdrs = [], hdrs = [],
    defines = select({"//:grpc_no_ares": ["GRPC_ARES=0"],
                      "//conditions:default": [],}) +
              select({"//:remote_execution":  ["GRPC_PORT_ISOLATED_RUNTIME=1"],
+                      "//conditions:default": [],}) +
+              select({"//:grpc_allow_exceptions":  ["GRPC_ALLOW_EXCEPTIONS=1"],
+                      "//:grpc_disallow_exceptions":
+                      ["GRPC_ALLOW_EXCEPTIONS=0"],
                      "//conditions:default": [],}),
    hdrs = _maybe_update_cc_library_hdrs(hdrs + public_hdrs),
    deps = deps + _get_external_deps(external_deps),
--- a/build.yaml
+++ b/build.yaml
@ -13,8 +13,8 @@ settings:
  '#09': Per-language overrides are possible with (eg) ruby_version tag here
  '#10': See the expand_version.py for all the quirks here
  core_version: 5.0.0-dev
-  g_stands_for: glossy
-  version: 1.9.0-dev
+  g_stands_for: glamorous
+  version: 1.10.0-dev
 filegroups:
 - name: census
  public_headers:
@ -26,50 +26,50 @@ filegroups:
  - nanopb
 - name: gpr_base
  src:
+  - src/core/lib/gpr/alloc.cc
+  - src/core/lib/gpr/arena.cc
+  - src/core/lib/gpr/atm.cc
+  - src/core/lib/gpr/avl.cc
+  - src/core/lib/gpr/cmdline.cc
+  - src/core/lib/gpr/cpu_iphone.cc
+  - src/core/lib/gpr/cpu_linux.cc
+  - src/core/lib/gpr/cpu_posix.cc
+  - src/core/lib/gpr/cpu_windows.cc
+  - src/core/lib/gpr/env_linux.cc
+  - src/core/lib/gpr/env_posix.cc
+  - src/core/lib/gpr/env_windows.cc
+  - src/core/lib/gpr/fork.cc
+  - src/core/lib/gpr/host_port.cc
+  - src/core/lib/gpr/log.cc
+  - src/core/lib/gpr/log_android.cc
+  - src/core/lib/gpr/log_linux.cc
+  - src/core/lib/gpr/log_posix.cc
+  - src/core/lib/gpr/log_windows.cc
+  - src/core/lib/gpr/mpscq.cc
+  - src/core/lib/gpr/murmur_hash.cc
+  - src/core/lib/gpr/string.cc
+  - src/core/lib/gpr/string_posix.cc
+  - src/core/lib/gpr/string_util_windows.cc
+  - src/core/lib/gpr/string_windows.cc
+  - src/core/lib/gpr/subprocess_posix.cc
+  - src/core/lib/gpr/subprocess_windows.cc
+  - src/core/lib/gpr/sync.cc
+  - src/core/lib/gpr/sync_posix.cc
+  - src/core/lib/gpr/sync_windows.cc
+  - src/core/lib/gpr/thd.cc
+  - src/core/lib/gpr/thd_posix.cc
+  - src/core/lib/gpr/thd_windows.cc
+  - src/core/lib/gpr/time.cc
+  - src/core/lib/gpr/time_posix.cc
+  - src/core/lib/gpr/time_precise.cc
+  - src/core/lib/gpr/time_windows.cc
+  - src/core/lib/gpr/tls_pthread.cc
+  - src/core/lib/gpr/tmpfile_msys.cc
+  - src/core/lib/gpr/tmpfile_posix.cc
+  - src/core/lib/gpr/tmpfile_windows.cc
+  - src/core/lib/gpr/wrap_memcpy.cc
  - src/core/lib/profiling/basic_timers.cc
  - src/core/lib/profiling/stap_timers.cc
-  - src/core/lib/support/alloc.cc
-  - src/core/lib/support/arena.cc
-  - src/core/lib/support/atm.cc
-  - src/core/lib/support/avl.cc
-  - src/core/lib/support/cmdline.cc
-  - src/core/lib/support/cpu_iphone.cc
-  - src/core/lib/support/cpu_linux.cc
-  - src/core/lib/support/cpu_posix.cc
-  - src/core/lib/support/cpu_windows.cc
-  - src/core/lib/support/env_linux.cc
-  - src/core/lib/support/env_posix.cc
-  - src/core/lib/support/env_windows.cc
-  - src/core/lib/support/fork.cc
-  - src/core/lib/support/host_port.cc
-  - src/core/lib/support/log.cc
-  - src/core/lib/support/log_android.cc
-  - src/core/lib/support/log_linux.cc
-  - src/core/lib/support/log_posix.cc
-  - src/core/lib/support/log_windows.cc
-  - src/core/lib/support/mpscq.cc
-  - src/core/lib/support/murmur_hash.cc
-  - src/core/lib/support/string.cc
-  - src/core/lib/support/string_posix.cc
-  - src/core/lib/support/string_util_windows.cc
-  - src/core/lib/support/string_windows.cc
-  - src/core/lib/support/subprocess_posix.cc
-  - src/core/lib/support/subprocess_windows.cc
-  - src/core/lib/support/sync.cc
-  - src/core/lib/support/sync_posix.cc
-  - src/core/lib/support/sync_windows.cc
-  - src/core/lib/support/thd.cc
-  - src/core/lib/support/thd_posix.cc
-  - src/core/lib/support/thd_windows.cc
-  - src/core/lib/support/time.cc
-  - src/core/lib/support/time_posix.cc
-  - src/core/lib/support/time_precise.cc
-  - src/core/lib/support/time_windows.cc
-  - src/core/lib/support/tls_pthread.cc
-  - src/core/lib/support/tmpfile_msys.cc
-  - src/core/lib/support/tmpfile_posix.cc
-  - src/core/lib/support/tmpfile_windows.cc
-  - src/core/lib/support/wrap_memcpy.cc
  uses:
  - gpr_base_headers
 - name: gpr_base_headers
@ -101,24 +101,24 @@ filegroups:
  - include/grpc/support/tls_pthread.h
  - include/grpc/support/useful.h
  headers:
+  - src/core/lib/gpr/arena.h
+  - src/core/lib/gpr/env.h
+  - src/core/lib/gpr/fork.h
+  - src/core/lib/gpr/mpscq.h
+  - src/core/lib/gpr/murmur_hash.h
+  - src/core/lib/gpr/spinlock.h
+  - src/core/lib/gpr/string.h
+  - src/core/lib/gpr/string_windows.h
+  - src/core/lib/gpr/thd_internal.h
+  - src/core/lib/gpr/time_precise.h
+  - src/core/lib/gpr/tmpfile.h
+  - src/core/lib/gprpp/abstract.h
+  - src/core/lib/gprpp/atomic.h
+  - src/core/lib/gprpp/atomic_with_atm.h
+  - src/core/lib/gprpp/atomic_with_std.h
+  - src/core/lib/gprpp/manual_constructor.h
+  - src/core/lib/gprpp/memory.h
  - src/core/lib/profiling/timers.h
-  - src/core/lib/support/abstract.h
-  - src/core/lib/support/arena.h
-  - src/core/lib/support/atomic.h
-  - src/core/lib/support/atomic_with_atm.h
-  - src/core/lib/support/atomic_with_std.h
-  - src/core/lib/support/env.h
-  - src/core/lib/support/fork.h
-  - src/core/lib/support/manual_constructor.h
-  - src/core/lib/support/memory.h
-  - src/core/lib/support/mpscq.h
-  - src/core/lib/support/murmur_hash.h
-  - src/core/lib/support/spinlock.h
-  - src/core/lib/support/string.h
-  - src/core/lib/support/string_windows.h
-  - src/core/lib/support/thd_internal.h
-  - src/core/lib/support/time_precise.h
-  - src/core/lib/support/tmpfile.h
  uses:
  - gpr_codegen
 - name: gpr_codegen
@ -321,6 +321,11 @@ filegroups:
  - src/core/lib/compression/stream_compression_identity.h
  - src/core/lib/debug/stats.h
  - src/core/lib/debug/stats_data.h
+  - src/core/lib/gprpp/debug_location.h
+  - src/core/lib/gprpp/inlined_vector.h
+  - src/core/lib/gprpp/orphanable.h
+  - src/core/lib/gprpp/ref_counted.h
+  - src/core/lib/gprpp/ref_counted_ptr.h
  - src/core/lib/http/format_request.h
  - src/core/lib/http/httpcli.h
  - src/core/lib/http/parser.h
@ -396,9 +401,6 @@ filegroups:
  - src/core/lib/slice/slice_hash_table.h
  - src/core/lib/slice/slice_internal.h
  - src/core/lib/slice/slice_string_helpers.h
-  - src/core/lib/support/debug_location.h
-  - src/core/lib/support/ref_counted.h
-  - src/core/lib/support/ref_counted_ptr.h
  - src/core/lib/surface/alarm_internal.h
  - src/core/lib/surface/api_trace.h
  - src/core/lib/surface/call.h
@ -485,7 +487,6 @@ filegroups:
  - include/grpc/impl/codegen/byte_buffer_reader.h
  - include/grpc/impl/codegen/compression_types.h
  - include/grpc/impl/codegen/connectivity_state.h
-  - include/grpc/impl/codegen/exec_ctx_fwd.h
  - include/grpc/impl/codegen/grpc_types.h
  - include/grpc/impl/codegen/propagation_bits.h
  - include/grpc/impl/codegen/slice.h
@ -1731,7 +1732,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/alloc_test.cc
+  - test/core/gpr/alloc_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -1764,7 +1765,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/arena_test.cc
+  - test/core/gpr/arena_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2131,7 +2132,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/avl_test.cc
+  - test/core/gpr/avl_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2140,7 +2141,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/cmdline_test.cc
+  - test/core/gpr/cmdline_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2150,7 +2151,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/cpu_test.cc
+  - test/core/gpr/cpu_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2159,7 +2160,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/env_test.cc
+  - test/core/gpr/env_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2168,7 +2169,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/host_port_test.cc
+  - test/core/gpr/host_port_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2177,7 +2178,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/log_test.cc
+  - test/core/gpr/log_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2187,7 +2188,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/manual_constructor_test.cc
+  - test/core/gprpp/manual_constructor_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2197,7 +2198,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/mpscq_test.cc
+  - test/core/gpr/mpscq_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2207,7 +2208,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/spinlock_test.cc
+  - test/core/gpr/spinlock_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2216,7 +2217,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/string_test.cc
+  - test/core/gpr/string_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2226,7 +2227,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/sync_test.cc
+  - test/core/gpr/sync_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2236,7 +2237,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/thd_test.cc
+  - test/core/gpr/thd_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2245,7 +2246,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/time_test.cc
+  - test/core/gpr/time_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2254,7 +2255,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/tls_test.cc
+  - test/core/gpr/tls_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2263,7 +2264,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/useful_test.cc
+  - test/core/gpr/useful_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -2832,7 +2833,7 @@ targets:
  build: test
  language: c
  src:
-  - test/core/support/murmur_hash_test.cc
+  - test/core/gpr/murmur_hash_test.cc
  deps:
  - gpr_test_util
  - gpr
@ -4007,6 +4008,19 @@ targets:
  deps:
  - grpc++_error_details
  - grpc++
+- name: exception_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/cpp/end2end/exception_test.cc
+  deps:
+  - grpc++_test_util
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: filter_end2end_test
  gtest: true
  build: test
@ -4246,6 +4260,20 @@ targets:
  - grpc
  - gpr_test_util
  - gpr
+- name: inlined_vector_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/core/gprpp/inlined_vector_test.cc
+  deps:
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
+  uses:
+  - grpc++_test
 - name: inproc_sync_unary_ping_pong_test
  build: test
  language: c++
@ -4343,7 +4371,7 @@ targets:
  build: test
  language: c++
  src:
-  - test/core/support/memory_test.cc
+  - test/core/gprpp/memory_test.cc
  deps:
  - grpc_test_util
  - grpc++
@ -4390,6 +4418,20 @@ targets:
  deps:
  - benchmark
  defaults: benchmark
+- name: orphanable_test
+  gtest: true
+  build: test
+  language: c++
+  src:
+  - test/core/gprpp/orphanable_test.cc
+  deps:
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
+  uses:
+  - grpc++_test
 - name: proto_server_reflection_test
  gtest: true
  build: test
@ -4534,7 +4576,7 @@ targets:
  build: test
  language: c++
  src:
-  - test/core/support/ref_counted_ptr_test.cc
+  - test/core/gprpp/ref_counted_ptr_test.cc
  deps:
  - grpc_test_util
  - grpc++
@ -4548,7 +4590,7 @@ targets:
  build: test
  language: c++
  src:
-  - test/core/support/ref_counted_test.cc
+  - test/core/gprpp/ref_counted_test.cc
  deps:
  - grpc_test_util
  - grpc++
@ -4913,7 +4955,6 @@ configs:
    DEFINES: NDEBUG
  dbg:
    CPPFLAGS: -O0
-    CXXFLAGS: -fno-exceptions
    DEFINES: _DEBUG DEBUG
  gcov:
    CC: gcc
@ -4954,10 +4995,13 @@ configs:
    CPPFLAGS: -O3 -fno-omit-frame-pointer
    DEFINES: NDEBUG
    LDFLAGS: -rdynamic
-  opt:
+  noexcept:
    CPPFLAGS: -O2
    CXXFLAGS: -fno-exceptions
    DEFINES: NDEBUG
+  opt:
+    CPPFLAGS: -O2
+    DEFINES: NDEBUG
  stapprof:
    CPPFLAGS: -O2 -DGRPC_STAP_PROFILER
    DEFINES: NDEBUG
@ -5004,6 +5048,7 @@ defaults:
  global:
    COREFLAGS: -fno-rtti -fno-exceptions
    CPPFLAGS: -g -Wall -Wextra -Werror -Wno-long-long -Wno-unused-parameter -DOSATOMIC_USE_INLINED=1
+      -Wno-deprecated-declarations
    LDFLAGS: -g
  zlib:
    CFLAGS: -Wno-sign-conversion -Wno-conversion -Wno-unused-value -Wno-implicit-function-declaration
--- a/cmake/benchmark.cmake
+++ b/cmake/benchmark.cmake
@ -20,14 +20,17 @@ if("${gRPC_BENCHMARK_PROVIDER}" STREQUAL "module")
      add_subdirectory(${BENCHMARK_ROOT_DIR} third_party/benchmark)
      if(TARGET benchmark)
          set(_gRPC_BENCHMARK_LIBRARIES benchmark)
+          set(_gRPC_BENCHMARK_INCLUDE_DIR "${BENCHMARK_ROOT_DIR}/include")
      endif()
  else()
      message(WARNING "gRPC_BENCHMARK_PROVIDER is \"module\" but BENCHMARK_ROOT_DIR is wrong")
  endif()
 elseif("${gRPC_BENCHMARK_PROVIDER}" STREQUAL "package")
-  find_package(benchmark)
+  find_package(benchmark REQUIRED)
  if(TARGET benchmark::benchmark)
    set(_gRPC_BENCHMARK_LIBRARIES benchmark::benchmark)
+    # extract the include dir from target's properties
+    get_target_property(_gRPC_BENCHMARK_INCLUDE_DIR benchmark::benchmark INTERFACE_INCLUDE_DIRECTORIES)
  endif()
  set(_gRPC_FIND_BENCHMARK "if(NOT benchmark_FOUND)\n  find_package(benchmark)\nendif()")
 endif()
--- a/cmake/cares.cmake
+++ b/cmake/cares.cmake
@ -18,11 +18,13 @@ if("${gRPC_CARES_PROVIDER}" STREQUAL "module")
  endif()
  set(CARES_SHARED OFF CACHE BOOL "disable shared library")
  set(CARES_STATIC ON CACHE BOOL "link cares statically")
-  set(CARES_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/third_party/cares/cares")
  add_subdirectory(third_party/cares/cares)
+
  if(TARGET c-ares)
    set(_gRPC_CARES_LIBRARIES c-ares)
+    set(_gRPC_CARES_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/third_party/cares/cares" "${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares")
  endif()
+
  if(gRPC_INSTALL)
    message(WARNING "gRPC_INSTALL will be forced to FALSE because gRPC_CARES_PROVIDER is \"module\"")
    set(gRPC_INSTALL FALSE)
@ -31,6 +33,7 @@ elseif("${gRPC_CARES_PROVIDER}" STREQUAL "package")
  find_package(c-ares REQUIRED CONFIG)
  if(TARGET c-ares::cares)
    set(_gRPC_CARES_LIBRARIES c-ares::cares)
+    set(_gRPC_CARES_INCLUDE_DIR ${c-ares_INCLUDE_DIR})
  endif()
  set(_gRPC_FIND_CARES "if(NOT c-ares_FOUND)\n  find_package(c-ares CONFIG)\nendif()")
 endif()
--- a/cmake/gflags.cmake
+++ b/cmake/gflags.cmake
@ -17,17 +17,19 @@ if("${gRPC_GFLAGS_PROVIDER}" STREQUAL "module")
    set(GFLAGS_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/gflags)
  endif()
  if(EXISTS "${GFLAGS_ROOT_DIR}/CMakeLists.txt")
-      add_subdirectory(${GFLAGS_ROOT_DIR} third_party/gflags)
-      if(TARGET gflags_static)
-          set(_gRPC_GFLAGS_LIBRARIES gflags_static)
-      endif()
+    add_subdirectory(${GFLAGS_ROOT_DIR} third_party/gflags)
+    if(TARGET gflags_static)
+      set(_gRPC_GFLAGS_LIBRARIES gflags_static)
+      set(_gRPC_GFLAGS_INCLUDE_DIR "${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include")
+    endif()
  else()
-      message(WARNING "gRPC_GFLAGS_PROVIDER is \"module\" but GFLAGS_ROOT_DIR is wrong")
+    message(WARNING "gRPC_GFLAGS_PROVIDER is \"module\" but GFLAGS_ROOT_DIR is wrong")
  endif()
 elseif("${gRPC_GFLAGS_PROVIDER}" STREQUAL "package")
-  find_package(gflags)
+  find_package(gflags REQUIRED)
  if(TARGET gflags::gflags)
    set(_gRPC_GFLAGS_LIBRARIES gflags::gflags)
+    set(_gRPC_GFLAGS_INCLUDE_DIR ${GFLAGS_INCLUDE_DIR})
  endif()
  set(_gRPC_FIND_GFLAGS "if(NOT gflags_FOUND)\n  find_package(gflags)\nendif()")
 endif()
--- a/cmake/protobuf.cmake
+++ b/cmake/protobuf.cmake
@ -27,7 +27,7 @@ if("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "module")
  if(NOT PROTOBUF_ROOT_DIR)
    set(PROTOBUF_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/protobuf)
  endif()
-  set(PROTOBUF_WELLKNOWN_IMPORT_DIR ${PROTOBUF_ROOT_DIR}/src)
+
  if(EXISTS "${PROTOBUF_ROOT_DIR}/cmake/CMakeLists.txt")
    set(protobuf_MSVC_STATIC_RUNTIME OFF CACHE BOOL "Link static runtime libraries")
    add_subdirectory(${PROTOBUF_ROOT_DIR}/cmake third_party/protobuf)
@ -41,6 +41,9 @@ if("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "module")
      set(_gRPC_PROTOBUF_PROTOC protoc)
      set(_gRPC_PROTOBUF_PROTOC_EXECUTABLE $<TARGET_FILE:protoc>)
    endif()
+    set(_gRPC_PROTOBUF_INCLUDE_DIR "${PROTOBUF_ROOT_DIR}")
+    # For well-known .proto files distributed with protobuf
+    set(_gRPC_PROTOBUF_WELLKNOWN_INCLUDE_DIR "${PROTOBUF_ROOT_DIR}/src")
  else()
      message(WARNING "gRPC_PROTOBUF_PROVIDER is \"module\" but PROTOBUF_ROOT_DIR is wrong")
  endif()
@ -50,6 +53,11 @@ if("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "module")
  endif()
 elseif("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "package")
  find_package(Protobuf REQUIRED ${gRPC_PROTOBUF_PACKAGE_TYPE})
+
+  # {Protobuf,PROTOBUF}_FOUND is defined based on find_package type ("MODULE" vs "CONFIG").
+  # For "MODULE", the case has also changed between cmake 3.5 and 3.6.
+  # We use the legacy uppercase version for *_LIBRARIES AND *_INCLUDE_DIRS variables
+  # as newer cmake versions provide them too for backward compatibility.
  if(Protobuf_FOUND OR PROTOBUF_FOUND)
    if(TARGET protobuf::${_gRPC_PROTOBUF_LIBRARY_NAME})
      set(_gRPC_PROTOBUF_LIBRARIES protobuf::${_gRPC_PROTOBUF_LIBRARY_NAME})
@ -58,8 +66,11 @@ elseif("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "package")
    endif()
    if(TARGET protobuf::libprotoc)
      set(_gRPC_PROTOBUF_PROTOC_LIBRARIES protobuf::libprotoc)
+      # extract the include dir from target's properties
+      get_target_property(_gRPC_PROTOBUF_WELLKNOWN_INCLUDE_DIR protobuf::libprotoc INTERFACE_INCLUDE_DIRECTORIES)
    else()
      set(_gRPC_PROTOBUF_PROTOC_LIBRARIES ${PROTOBUF_PROTOC_LIBRARIES})
+      set(_gRPC_PROTOBUF_WELLKNOWN_INCLUDE_DIR ${PROTOBUF_INCLUDE_DIRS})
    endif()
    if(TARGET protobuf::protoc)
      set(_gRPC_PROTOBUF_PROTOC protobuf::protoc)
@ -68,10 +79,7 @@ elseif("${gRPC_PROTOBUF_PROVIDER}" STREQUAL "package")
      set(_gRPC_PROTOBUF_PROTOC ${PROTOBUF_PROTOC_EXECUTABLE})
      set(_gRPC_PROTOBUF_PROTOC_EXECUTABLE ${PROTOBUF_PROTOC_EXECUTABLE})
    endif()
+    set(_gRPC_PROTOBUF_INCLUDE_DIR ${PROTOBUF_INCLUDE_DIRS})
    set(_gRPC_FIND_PROTOBUF "if(NOT Protobuf_FOUND AND NOT PROTOBUF_FOUND)\n  find_package(Protobuf ${gRPC_PROTOBUF_PACKAGE_TYPE})\nendif()")
  endif()
-  if(PROTOBUF_FOUND)
-    include_directories(${PROTOBUF_INCLUDE_DIRS})
-  endif()
-  set(PROTOBUF_WELLKNOWN_IMPORT_DIR /usr/local/include)
 endif()
--- a/cmake/zlib.cmake
+++ b/cmake/zlib.cmake
@ -16,15 +16,15 @@ if("${gRPC_ZLIB_PROVIDER}" STREQUAL "module")
  if(NOT ZLIB_ROOT_DIR)
    set(ZLIB_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third_party/zlib)
  endif()
-  set(ZLIB_INCLUDE_DIR "${ZLIB_ROOT_DIR}")
  if(EXISTS "${ZLIB_ROOT_DIR}/CMakeLists.txt")
-      # TODO(jtattermusch): workaround for https://github.com/madler/zlib/issues/218
-      include_directories(${ZLIB_INCLUDE_DIR})
+    # TODO(jtattermusch): workaround for https://github.com/madler/zlib/issues/218
+    include_directories("${ZLIB_ROOT_DIR}")
+    add_subdirectory(${ZLIB_ROOT_DIR} third_party/zlib)

-      add_subdirectory(${ZLIB_ROOT_DIR} third_party/zlib)
-      if(TARGET zlibstatic)
-          set(_gRPC_ZLIB_LIBRARIES zlibstatic)
-      endif()
+    if(TARGET zlibstatic)
+      set(_gRPC_ZLIB_LIBRARIES zlibstatic)
+      set(_gRPC_ZLIB_INCLUDE_DIR "${ZLIB_ROOT_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib")
+    endif()
  else()
      message(WARNING "gRPC_ZLIB_PROVIDER is \"module\" but ZLIB_ROOT_DIR is wrong")
  endif()
@ -35,5 +35,6 @@ if("${gRPC_ZLIB_PROVIDER}" STREQUAL "module")
 elseif("${gRPC_ZLIB_PROVIDER}" STREQUAL "package")
  find_package(ZLIB REQUIRED)
  set(_gRPC_ZLIB_LIBRARIES ${ZLIB_LIBRARIES})
+  set(_gRPC_ZLIB_INCLUDE_DIR ${ZLIB_INCLUDE_DIRS})
  set(_gRPC_FIND_ZLIB "if(NOT ZLIB_FOUND)\n  find_package(ZLIB)\nendif()")
 endif()
--- a/config.m4
+++ b/config.m4
@ -39,50 +39,50 @@ if test "$PHP_GRPC" != "no"; then
    src/php/ext/grpc/server.c \
    src/php/ext/grpc/server_credentials.c \
    src/php/ext/grpc/timeval.c \
+    src/core/lib/gpr/alloc.cc \
+    src/core/lib/gpr/arena.cc \
+    src/core/lib/gpr/atm.cc \
+    src/core/lib/gpr/avl.cc \
+    src/core/lib/gpr/cmdline.cc \
+    src/core/lib/gpr/cpu_iphone.cc \
+    src/core/lib/gpr/cpu_linux.cc \
+    src/core/lib/gpr/cpu_posix.cc \
+    src/core/lib/gpr/cpu_windows.cc \
+    src/core/lib/gpr/env_linux.cc \
+    src/core/lib/gpr/env_posix.cc \
+    src/core/lib/gpr/env_windows.cc \
+    src/core/lib/gpr/fork.cc \
+    src/core/lib/gpr/host_port.cc \
+    src/core/lib/gpr/log.cc \
+    src/core/lib/gpr/log_android.cc \
+    src/core/lib/gpr/log_linux.cc \
+    src/core/lib/gpr/log_posix.cc \
+    src/core/lib/gpr/log_windows.cc \
+    src/core/lib/gpr/mpscq.cc \
+    src/core/lib/gpr/murmur_hash.cc \
+    src/core/lib/gpr/string.cc \
+    src/core/lib/gpr/string_posix.cc \
+    src/core/lib/gpr/string_util_windows.cc \
+    src/core/lib/gpr/string_windows.cc \
+    src/core/lib/gpr/subprocess_posix.cc \
+    src/core/lib/gpr/subprocess_windows.cc \
+    src/core/lib/gpr/sync.cc \
+    src/core/lib/gpr/sync_posix.cc \
+    src/core/lib/gpr/sync_windows.cc \
+    src/core/lib/gpr/thd.cc \
+    src/core/lib/gpr/thd_posix.cc \
+    src/core/lib/gpr/thd_windows.cc \
+    src/core/lib/gpr/time.cc \
+    src/core/lib/gpr/time_posix.cc \
+    src/core/lib/gpr/time_precise.cc \
+    src/core/lib/gpr/time_windows.cc \
+    src/core/lib/gpr/tls_pthread.cc \
+    src/core/lib/gpr/tmpfile_msys.cc \
+    src/core/lib/gpr/tmpfile_posix.cc \
+    src/core/lib/gpr/tmpfile_windows.cc \
+    src/core/lib/gpr/wrap_memcpy.cc \
    src/core/lib/profiling/basic_timers.cc \
    src/core/lib/profiling/stap_timers.cc \
-    src/core/lib/support/alloc.cc \
-    src/core/lib/support/arena.cc \
-    src/core/lib/support/atm.cc \
-    src/core/lib/support/avl.cc \
-    src/core/lib/support/cmdline.cc \
-    src/core/lib/support/cpu_iphone.cc \
-    src/core/lib/support/cpu_linux.cc \
-    src/core/lib/support/cpu_posix.cc \
-    src/core/lib/support/cpu_windows.cc \
-    src/core/lib/support/env_linux.cc \
-    src/core/lib/support/env_posix.cc \
-    src/core/lib/support/env_windows.cc \
-    src/core/lib/support/fork.cc \
-    src/core/lib/support/host_port.cc \
-    src/core/lib/support/log.cc \
-    src/core/lib/support/log_android.cc \
-    src/core/lib/support/log_linux.cc \
-    src/core/lib/support/log_posix.cc \
-    src/core/lib/support/log_windows.cc \
-    src/core/lib/support/mpscq.cc \
-    src/core/lib/support/murmur_hash.cc \
-    src/core/lib/support/string.cc \
-    src/core/lib/support/string_posix.cc \
-    src/core/lib/support/string_util_windows.cc \
-    src/core/lib/support/string_windows.cc \
-    src/core/lib/support/subprocess_posix.cc \
-    src/core/lib/support/subprocess_windows.cc \
-    src/core/lib/support/sync.cc \
-    src/core/lib/support/sync_posix.cc \
-    src/core/lib/support/sync_windows.cc \
-    src/core/lib/support/thd.cc \
-    src/core/lib/support/thd_posix.cc \
-    src/core/lib/support/thd_windows.cc \
-    src/core/lib/support/time.cc \
-    src/core/lib/support/time_posix.cc \
-    src/core/lib/support/time_precise.cc \
-    src/core/lib/support/time_windows.cc \
-    src/core/lib/support/tls_pthread.cc \
-    src/core/lib/support/tmpfile_msys.cc \
-    src/core/lib/support/tmpfile_posix.cc \
-    src/core/lib/support/tmpfile_windows.cc \
-    src/core/lib/support/wrap_memcpy.cc \
    src/core/lib/surface/init.cc \
    src/core/lib/backoff/backoff.cc \
    src/core/lib/channel/channel_args.cc \
@ -678,6 +678,7 @@ if test "$PHP_GRPC" != "no"; then
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/channel)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/compression)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/debug)
+  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/gpr)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/http)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/iomgr)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/json)
@ -695,7 +696,6 @@ if test "$PHP_GRPC" != "no"; then
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/security/transport)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/security/util)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/slice)
-  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/support)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/surface)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/lib/transport)
  PHP_ADD_BUILD_DIR($ext_builddir/src/core/plugin_registry)
--- a/config.w32
+++ b/config.w32
@ -16,50 +16,50 @@ if (PHP_GRPC != "no") {
    "src\\php\\ext\\grpc\\server.c " +
    "src\\php\\ext\\grpc\\server_credentials.c " +
    "src\\php\\ext\\grpc\\timeval.c " +
+    "src\\core\\lib\\gpr\\alloc.cc " +
+    "src\\core\\lib\\gpr\\arena.cc " +
+    "src\\core\\lib\\gpr\\atm.cc " +
+    "src\\core\\lib\\gpr\\avl.cc " +
+    "src\\core\\lib\\gpr\\cmdline.cc " +
+    "src\\core\\lib\\gpr\\cpu_iphone.cc " +
+    "src\\core\\lib\\gpr\\cpu_linux.cc " +
+    "src\\core\\lib\\gpr\\cpu_posix.cc " +
+    "src\\core\\lib\\gpr\\cpu_windows.cc " +
+    "src\\core\\lib\\gpr\\env_linux.cc " +
+    "src\\core\\lib\\gpr\\env_posix.cc " +
+    "src\\core\\lib\\gpr\\env_windows.cc " +
+    "src\\core\\lib\\gpr\\fork.cc " +
+    "src\\core\\lib\\gpr\\host_port.cc " +
+    "src\\core\\lib\\gpr\\log.cc " +
+    "src\\core\\lib\\gpr\\log_android.cc " +
+    "src\\core\\lib\\gpr\\log_linux.cc " +
+    "src\\core\\lib\\gpr\\log_posix.cc " +
+    "src\\core\\lib\\gpr\\log_windows.cc " +
+    "src\\core\\lib\\gpr\\mpscq.cc " +
+    "src\\core\\lib\\gpr\\murmur_hash.cc " +
+    "src\\core\\lib\\gpr\\string.cc " +
+    "src\\core\\lib\\gpr\\string_posix.cc " +
+    "src\\core\\lib\\gpr\\string_util_windows.cc " +
+    "src\\core\\lib\\gpr\\string_windows.cc " +
+    "src\\core\\lib\\gpr\\subprocess_posix.cc " +
+    "src\\core\\lib\\gpr\\subprocess_windows.cc " +
+    "src\\core\\lib\\gpr\\sync.cc " +
+    "src\\core\\lib\\gpr\\sync_posix.cc " +
+    "src\\core\\lib\\gpr\\sync_windows.cc " +
+    "src\\core\\lib\\gpr\\thd.cc " +
+    "src\\core\\lib\\gpr\\thd_posix.cc " +
+    "src\\core\\lib\\gpr\\thd_windows.cc " +
+    "src\\core\\lib\\gpr\\time.cc " +
+    "src\\core\\lib\\gpr\\time_posix.cc " +
+    "src\\core\\lib\\gpr\\time_precise.cc " +
+    "src\\core\\lib\\gpr\\time_windows.cc " +
+    "src\\core\\lib\\gpr\\tls_pthread.cc " +
+    "src\\core\\lib\\gpr\\tmpfile_msys.cc " +
+    "src\\core\\lib\\gpr\\tmpfile_posix.cc " +
+    "src\\core\\lib\\gpr\\tmpfile_windows.cc " +
+    "src\\core\\lib\\gpr\\wrap_memcpy.cc " +
    "src\\core\\lib\\profiling\\basic_timers.cc " +
    "src\\core\\lib\\profiling\\stap_timers.cc " +
-    "src\\core\\lib\\support\\alloc.cc " +
-    "src\\core\\lib\\support\\arena.cc " +
-    "src\\core\\lib\\support\\atm.cc " +
-    "src\\core\\lib\\support\\avl.cc " +
-    "src\\core\\lib\\support\\cmdline.cc " +
-    "src\\core\\lib\\support\\cpu_iphone.cc " +
-    "src\\core\\lib\\support\\cpu_linux.cc " +
-    "src\\core\\lib\\support\\cpu_posix.cc " +
-    "src\\core\\lib\\support\\cpu_windows.cc " +
-    "src\\core\\lib\\support\\env_linux.cc " +
-    "src\\core\\lib\\support\\env_posix.cc " +
-    "src\\core\\lib\\support\\env_windows.cc " +
-    "src\\core\\lib\\support\\fork.cc " +
-    "src\\core\\lib\\support\\host_port.cc " +
-    "src\\core\\lib\\support\\log.cc " +
-    "src\\core\\lib\\support\\log_android.cc " +
-    "src\\core\\lib\\support\\log_linux.cc " +
-    "src\\core\\lib\\support\\log_posix.cc " +
-    "src\\core\\lib\\support\\log_windows.cc " +
-    "src\\core\\lib\\support\\mpscq.cc " +
-    "src\\core\\lib\\support\\murmur_hash.cc " +
-    "src\\core\\lib\\support\\string.cc " +
-    "src\\core\\lib\\support\\string_posix.cc " +
-    "src\\core\\lib\\support\\string_util_windows.cc " +
-    "src\\core\\lib\\support\\string_windows.cc " +
-    "src\\core\\lib\\support\\subprocess_posix.cc " +
-    "src\\core\\lib\\support\\subprocess_windows.cc " +
-    "src\\core\\lib\\support\\sync.cc " +
-    "src\\core\\lib\\support\\sync_posix.cc " +
-    "src\\core\\lib\\support\\sync_windows.cc " +
-    "src\\core\\lib\\support\\thd.cc " +
-    "src\\core\\lib\\support\\thd_posix.cc " +
-    "src\\core\\lib\\support\\thd_windows.cc " +
-    "src\\core\\lib\\support\\time.cc " +
-    "src\\core\\lib\\support\\time_posix.cc " +
-    "src\\core\\lib\\support\\time_precise.cc " +
-    "src\\core\\lib\\support\\time_windows.cc " +
-    "src\\core\\lib\\support\\tls_pthread.cc " +
-    "src\\core\\lib\\support\\tmpfile_msys.cc " +
-    "src\\core\\lib\\support\\tmpfile_posix.cc " +
-    "src\\core\\lib\\support\\tmpfile_windows.cc " +
-    "src\\core\\lib\\support\\wrap_memcpy.cc " +
    "src\\core\\lib\\surface\\init.cc " +
    "src\\core\\lib\\backoff\\backoff.cc " +
    "src\\core\\lib\\channel\\channel_args.cc " +
@ -690,6 +690,7 @@ if (PHP_GRPC != "no") {
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\channel");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\compression");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\debug");
+  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\gpr");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\http");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\iomgr");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\json");
@ -708,7 +709,6 @@ if (PHP_GRPC != "no") {
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\security\\transport");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\security\\util");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\slice");
-  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\support");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\surface");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\lib\\transport");
  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\plugin_registry");
--- a/doc/environment_variables.md
+++ b/doc/environment_variables.md
@ -127,3 +127,8 @@ some configuration as environment variables that can be set.
  there is no active polling thread. They help reconnect disconnected client
  channels (mostly due to idleness), so that the next RPC on this channel won't
  fail. Set to 0 to turn off the backup polls.
+
+* GRPC_EXPERIMENTAL_DISABLE_FLOW_CONTROL
+  if set, flow control will be effectively disabled. Max out all values and
+  assume the remote peer does the same. Thus we can ignore any flow control
+  bookkeeping, error checking, and decision making
--- a/doc/g_stands_for.md
+++ b/doc/g_stands_for.md
@ -13,3 +13,4 @@ future), and the corresponding version numbers that used them:
 - 1.7 'g' stands for 'gambit'
 - 1.8 'g' stands for 'generous'
 - 1.9 'g' stands for 'glossy'
+- 1.10 'g' stands for 'glamorous'
--- a/doc/md
+++ b/doc/md
--- a/examples/cpp/helloworld/CMakeLists.txt
+++ b/examples/cpp/helloworld/CMakeLists.txt
@ -16,15 +16,22 @@ endif()
 find_package(Protobuf REQUIRED)
 message(STATUS "Using protobuf ${protobuf_VERSION}")

-if(Protobuf_FOUND)
-  # Protobuf_FOUND is set for package type "CONFIG"
-  set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)
-  set(_PROTOBUF_PROTOC protobuf::protoc)
-elseif(PROTOBUF_FOUND)
-  # PROTOBUF_FOUND is set for package type "MODULE"
-  set(_PROTOBUF_LIBPROTOBUF ${PROTOBUF_LIBRARIES})
-  set(_PROTOBUF_PROTOC ${PROTOBUF_PROTOC_EXECUTABLE})
-  include_directories(${PROTOBUF_INCLUDE_DIRS})
+# {Protobuf,PROTOBUF}_FOUND is defined based on find_package type ("MODULE" vs "CONFIG").
+# For "MODULE", the case has also changed between cmake 3.5 and 3.6.
+# We use the legacy uppercase version for *_LIBRARIES AND *_INCLUDE_DIRS variables
+# as newer cmake versions provide them too for backward compatibility.
+if(Protobuf_FOUND OR PROTOBUF_FOUND)
+  if(TARGET protobuf::libprotobuf)
+    set(_PROTOBUF_LIBPROTOBUF protobuf::libprotobuf)
+  else()
+    set(_PROTOBUF_LIBPROTOBUF ${PROTOBUF_LIBRARIES})
+    include_directories(${PROTOBUF_INCLUDE_DIRS})
+  endif()
+  if(TARGET protobuf::protoc)
+    set(_PROTOBUF_PROTOC $<TARGET_FILE:protobuf::protoc>)
+  else()
+    set(_PROTOBUF_PROTOC ${PROTOBUF_PROTOC_EXECUTABLE})
+  endif()
 else()
  message(WARNING "Failed to locate libprotobuf and protoc!")
 endif()
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@ -22,7 +22,7 @@

 Pod::Spec.new do |s|
  s.name     = 'gRPC-Core'
-  version = '1.9.0-dev'
+  version = '1.10.0-dev'
  s.version  = version
  s.summary  = 'Core cross-platform gRPC library, written in C'
  s.homepage = 'https://grpc.io'
@ -84,7 +84,7 @@ Pod::Spec.new do |s|
    'HEADER_SEARCH_PATHS' => '"$(inherited)" "$(GRPC_SRC_ROOT)/include"',
    'USER_HEADER_SEARCH_PATHS' => '"$(GRPC_SRC_ROOT)"',
    # If we don't set these two settings, `include/grpc/support/time.h` and
-    # `src/core/lib/support/string.h` shadow the system `<time.h>` and `<string.h>`, breaking the
+    # `src/core/lib/gpr/string.h` shadow the system `<time.h>` and `<string.h>`, breaking the
    # build.
    'USE_HEADERMAP' => 'NO',
    'ALWAYS_SEARCH_USER_PATHS' => 'NO',
@ -152,7 +152,6 @@ Pod::Spec.new do |s|
                      'include/grpc/impl/codegen/byte_buffer_reader.h',
                      'include/grpc/impl/codegen/compression_types.h',
                      'include/grpc/impl/codegen/connectivity_state.h',
-                      'include/grpc/impl/codegen/exec_ctx_fwd.h',
                      'include/grpc/impl/codegen/grpc_types.h',
                      'include/grpc/impl/codegen/propagation_bits.h',
                      'include/grpc/impl/codegen/slice.h',
@ -193,68 +192,68 @@ Pod::Spec.new do |s|
    ss.dependency 'nanopb', '~> 0.3'

    # To save you from scrolling, this is the last part of the podspec.
-    ss.source_files = 'src/core/lib/profiling/timers.h',
-                      'src/core/lib/support/abstract.h',
-                      'src/core/lib/support/arena.h',
-                      'src/core/lib/support/atomic.h',
-                      'src/core/lib/support/atomic_with_atm.h',
-                      'src/core/lib/support/atomic_with_std.h',
-                      'src/core/lib/support/env.h',
-                      'src/core/lib/support/fork.h',
-                      'src/core/lib/support/manual_constructor.h',
-                      'src/core/lib/support/memory.h',
-                      'src/core/lib/support/mpscq.h',
-                      'src/core/lib/support/murmur_hash.h',
-                      'src/core/lib/support/spinlock.h',
-                      'src/core/lib/support/string.h',
-                      'src/core/lib/support/string_windows.h',
-                      'src/core/lib/support/thd_internal.h',
-                      'src/core/lib/support/time_precise.h',
-                      'src/core/lib/support/tmpfile.h',
+    ss.source_files = 'src/core/lib/gpr/arena.h',
+                      'src/core/lib/gpr/env.h',
+                      'src/core/lib/gpr/fork.h',
+                      'src/core/lib/gpr/mpscq.h',
+                      'src/core/lib/gpr/murmur_hash.h',
+                      'src/core/lib/gpr/spinlock.h',
+                      'src/core/lib/gpr/string.h',
+                      'src/core/lib/gpr/string_windows.h',
+                      'src/core/lib/gpr/thd_internal.h',
+                      'src/core/lib/gpr/time_precise.h',
+                      'src/core/lib/gpr/tmpfile.h',
+                      'src/core/lib/gprpp/abstract.h',
+                      'src/core/lib/gprpp/atomic.h',
+                      'src/core/lib/gprpp/atomic_with_atm.h',
+                      'src/core/lib/gprpp/atomic_with_std.h',
+                      'src/core/lib/gprpp/manual_constructor.h',
+                      'src/core/lib/gprpp/memory.h',
+                      'src/core/lib/profiling/timers.h',
+                      'src/core/lib/gpr/alloc.cc',
+                      'src/core/lib/gpr/arena.cc',
+                      'src/core/lib/gpr/atm.cc',
+                      'src/core/lib/gpr/avl.cc',
+                      'src/core/lib/gpr/cmdline.cc',
+                      'src/core/lib/gpr/cpu_iphone.cc',
+                      'src/core/lib/gpr/cpu_linux.cc',
+                      'src/core/lib/gpr/cpu_posix.cc',
+                      'src/core/lib/gpr/cpu_windows.cc',
+                      'src/core/lib/gpr/env_linux.cc',
+                      'src/core/lib/gpr/env_posix.cc',
+                      'src/core/lib/gpr/env_windows.cc',
+                      'src/core/lib/gpr/fork.cc',
+                      'src/core/lib/gpr/host_port.cc',
+                      'src/core/lib/gpr/log.cc',
+                      'src/core/lib/gpr/log_android.cc',
+                      'src/core/lib/gpr/log_linux.cc',
+                      'src/core/lib/gpr/log_posix.cc',
+                      'src/core/lib/gpr/log_windows.cc',
+                      'src/core/lib/gpr/mpscq.cc',
+                      'src/core/lib/gpr/murmur_hash.cc',
+                      'src/core/lib/gpr/string.cc',
+                      'src/core/lib/gpr/string_posix.cc',
+                      'src/core/lib/gpr/string_util_windows.cc',
+                      'src/core/lib/gpr/string_windows.cc',
+                      'src/core/lib/gpr/subprocess_posix.cc',
+                      'src/core/lib/gpr/subprocess_windows.cc',
+                      'src/core/lib/gpr/sync.cc',
+                      'src/core/lib/gpr/sync_posix.cc',
+                      'src/core/lib/gpr/sync_windows.cc',
+                      'src/core/lib/gpr/thd.cc',
+                      'src/core/lib/gpr/thd_posix.cc',
+                      'src/core/lib/gpr/thd_windows.cc',
+                      'src/core/lib/gpr/time.cc',
+                      'src/core/lib/gpr/time_posix.cc',
+                      'src/core/lib/gpr/time_precise.cc',
+                      'src/core/lib/gpr/time_windows.cc',
+                      'src/core/lib/gpr/tls_pthread.cc',
+                      'src/core/lib/gpr/tmpfile_msys.cc',
+                      'src/core/lib/gpr/tmpfile_posix.cc',
+                      'src/core/lib/gpr/tmpfile_windows.cc',
+                      'src/core/lib/gpr/wrap_memcpy.cc',
                      'src/core/lib/profiling/basic_timers.cc',
                      'src/core/lib/profiling/stap_timers.cc',
-                      'src/core/lib/support/alloc.cc',
-                      'src/core/lib/support/arena.cc',
-                      'src/core/lib/support/atm.cc',
-                      'src/core/lib/support/avl.cc',
-                      'src/core/lib/support/cmdline.cc',
-                      'src/core/lib/support/cpu_iphone.cc',
-                      'src/core/lib/support/cpu_linux.cc',
-                      'src/core/lib/support/cpu_posix.cc',
-                      'src/core/lib/support/cpu_windows.cc',
-                      'src/core/lib/support/env_linux.cc',
-                      'src/core/lib/support/env_posix.cc',
-                      'src/core/lib/support/env_windows.cc',
-                      'src/core/lib/support/fork.cc',
-                      'src/core/lib/support/host_port.cc',
-                      'src/core/lib/support/log.cc',
-                      'src/core/lib/support/log_android.cc',
-                      'src/core/lib/support/log_linux.cc',
-                      'src/core/lib/support/log_posix.cc',
-                      'src/core/lib/support/log_windows.cc',
-                      'src/core/lib/support/mpscq.cc',
-                      'src/core/lib/support/murmur_hash.cc',
-                      'src/core/lib/support/string.cc',
-                      'src/core/lib/support/string_posix.cc',
-                      'src/core/lib/support/string_util_windows.cc',
-                      'src/core/lib/support/string_windows.cc',
-                      'src/core/lib/support/subprocess_posix.cc',
-                      'src/core/lib/support/subprocess_windows.cc',
-                      'src/core/lib/support/sync.cc',
-                      'src/core/lib/support/sync_posix.cc',
-                      'src/core/lib/support/sync_windows.cc',
-                      'src/core/lib/support/thd.cc',
-                      'src/core/lib/support/thd_posix.cc',
-                      'src/core/lib/support/thd_windows.cc',
-                      'src/core/lib/support/time.cc',
-                      'src/core/lib/support/time_posix.cc',
-                      'src/core/lib/support/time_precise.cc',
-                      'src/core/lib/support/time_windows.cc',
-                      'src/core/lib/support/tls_pthread.cc',
-                      'src/core/lib/support/tmpfile_msys.cc',
-                      'src/core/lib/support/tmpfile_posix.cc',
-                      'src/core/lib/support/tmpfile_windows.cc',
-                      'src/core/lib/support/wrap_memcpy.cc',
                      'src/core/ext/transport/chttp2/transport/bin_decoder.h',
                      'src/core/ext/transport/chttp2/transport/bin_encoder.h',
                      'src/core/ext/transport/chttp2/transport/chttp2_transport.h',
@ -345,6 +344,11 @@ Pod::Spec.new do |s|
                      'src/core/lib/compression/stream_compression_identity.h',
                      'src/core/lib/debug/stats.h',
                      'src/core/lib/debug/stats_data.h',
+                      'src/core/lib/gprpp/debug_location.h',
+                      'src/core/lib/gprpp/inlined_vector.h',
+                      'src/core/lib/gprpp/orphanable.h',
+                      'src/core/lib/gprpp/ref_counted.h',
+                      'src/core/lib/gprpp/ref_counted_ptr.h',
                      'src/core/lib/http/format_request.h',
                      'src/core/lib/http/httpcli.h',
                      'src/core/lib/http/parser.h',
@ -420,9 +424,6 @@ Pod::Spec.new do |s|
                      'src/core/lib/slice/slice_hash_table.h',
                      'src/core/lib/slice/slice_internal.h',
                      'src/core/lib/slice/slice_string_helpers.h',
-                      'src/core/lib/support/debug_location.h',
-                      'src/core/lib/support/ref_counted.h',
-                      'src/core/lib/support/ref_counted_ptr.h',
                      'src/core/lib/surface/alarm_internal.h',
                      'src/core/lib/surface/api_trace.h',
                      'src/core/lib/surface/call.h',
@ -717,24 +718,24 @@ Pod::Spec.new do |s|
                      'src/core/ext/filters/workarounds/workaround_utils.cc',
                      'src/core/plugin_registry/grpc_plugin_registry.cc'

-    ss.private_header_files = 'src/core/lib/profiling/timers.h',
-                              'src/core/lib/support/abstract.h',
-                              'src/core/lib/support/arena.h',
-                              'src/core/lib/support/atomic.h',
-                              'src/core/lib/support/atomic_with_atm.h',
-                              'src/core/lib/support/atomic_with_std.h',
-                              'src/core/lib/support/env.h',
-                              'src/core/lib/support/fork.h',
-                              'src/core/lib/support/manual_constructor.h',
-                              'src/core/lib/support/memory.h',
-                              'src/core/lib/support/mpscq.h',
-                              'src/core/lib/support/murmur_hash.h',
-                              'src/core/lib/support/spinlock.h',
-                              'src/core/lib/support/string.h',
-                              'src/core/lib/support/string_windows.h',
-                              'src/core/lib/support/thd_internal.h',
-                              'src/core/lib/support/time_precise.h',
-                              'src/core/lib/support/tmpfile.h',
+    ss.private_header_files = 'src/core/lib/gpr/arena.h',
+                              'src/core/lib/gpr/env.h',
+                              'src/core/lib/gpr/fork.h',
+                              'src/core/lib/gpr/mpscq.h',
+                              'src/core/lib/gpr/murmur_hash.h',
+                              'src/core/lib/gpr/spinlock.h',
+                              'src/core/lib/gpr/string.h',
+                              'src/core/lib/gpr/string_windows.h',
+                              'src/core/lib/gpr/thd_internal.h',
+                              'src/core/lib/gpr/time_precise.h',
+                              'src/core/lib/gpr/tmpfile.h',
+                              'src/core/lib/gprpp/abstract.h',
+                              'src/core/lib/gprpp/atomic.h',
+                              'src/core/lib/gprpp/atomic_with_atm.h',
+                              'src/core/lib/gprpp/atomic_with_std.h',
+                              'src/core/lib/gprpp/manual_constructor.h',
+                              'src/core/lib/gprpp/memory.h',
+                              'src/core/lib/profiling/timers.h',
                              'src/core/ext/transport/chttp2/transport/bin_decoder.h',
                              'src/core/ext/transport/chttp2/transport/bin_encoder.h',
                              'src/core/ext/transport/chttp2/transport/chttp2_transport.h',
@ -825,6 +826,11 @@ Pod::Spec.new do |s|
                              'src/core/lib/compression/stream_compression_identity.h',
                              'src/core/lib/debug/stats.h',
                              'src/core/lib/debug/stats_data.h',
+                              'src/core/lib/gprpp/debug_location.h',
+                              'src/core/lib/gprpp/inlined_vector.h',
+                              'src/core/lib/gprpp/orphanable.h',
+                              'src/core/lib/gprpp/ref_counted.h',
+                              'src/core/lib/gprpp/ref_counted_ptr.h',
                              'src/core/lib/http/format_request.h',
                              'src/core/lib/http/httpcli.h',
                              'src/core/lib/http/parser.h',
@ -900,9 +906,6 @@ Pod::Spec.new do |s|
                              'src/core/lib/slice/slice_hash_table.h',
                              'src/core/lib/slice/slice_internal.h',
                              'src/core/lib/slice/slice_string_helpers.h',
-                              'src/core/lib/support/debug_location.h',
-                              'src/core/lib/support/ref_counted.h',
-                              'src/core/lib/support/ref_counted_ptr.h',
                              'src/core/lib/surface/alarm_internal.h',
                              'src/core/lib/surface/api_trace.h',
                              'src/core/lib/surface/call.h',
@ -1038,6 +1041,7 @@ Pod::Spec.new do |s|
                      'test/core/end2end/tests/filter_call_init_fails.cc',
                      'test/core/end2end/tests/filter_causes_close.cc',
                      'test/core/end2end/tests/filter_latency.cc',
+                      'test/core/end2end/tests/filter_status_code.cc',
                      'test/core/end2end/tests/graceful_server_shutdown.cc',
                      'test/core/end2end/tests/high_initial_seqno.cc',
                      'test/core/end2end/tests/hpack_size.cc',
@ -1083,6 +1087,6 @@ Pod::Spec.new do |s|

  # TODO (mxyan): Instead of this hack, add include path "third_party" to C core's include path?
  s.prepare_command = <<-END_OF_COMMAND
-    find src/core/ -type f -exec sed -E -i '.back' 's;#include "third_party/nanopb/(.*)";#include <nanopb/\\1>;g' {} \\\;
+    find src/core/ -type f -exec sed -E -i'.back' 's;#include "third_party/nanopb/(.*)";#include <nanopb/\\1>;g' {} \\\;
  END_OF_COMMAND
 end
--- a/gRPC-ProtoRPC.podspec
+++ b/gRPC-ProtoRPC.podspec
@ -21,7 +21,7 @@

 Pod::Spec.new do |s|
  s.name     = 'gRPC-ProtoRPC'
-  version = '1.9.0-dev'
+  version = '1.10.0-dev'
  s.version  = version
  s.summary  = 'RPC library for Protocol Buffers, based on gRPC'
  s.homepage = 'https://grpc.io'
--- a/gRPC-RxLibrary.podspec
+++ b/gRPC-RxLibrary.podspec
@ -21,7 +21,7 @@

 Pod::Spec.new do |s|
  s.name     = 'gRPC-RxLibrary'
-  version = '1.9.0-dev'
+  version = '1.10.0-dev'
  s.version  = version
  s.summary  = 'Reactive Extensions library for iOS/OSX.'
  s.homepage = 'https://grpc.io'
--- a/gRPC.podspec
+++ b/gRPC.podspec
@ -20,7 +20,7 @@

 Pod::Spec.new do |s|
  s.name     = 'gRPC'
-  version = '1.9.0-dev'
+  version = '1.10.0-dev'
  s.version  = version
  s.summary  = 'gRPC client library for iOS/OSX'
  s.homepage = 'https://grpc.io'
--- a/grpc.gemspec
+++ b/grpc.gemspec
@ -83,73 +83,72 @@ Gem::Specification.new do |s|
  s.files += %w( include/grpc/impl/codegen/sync_generic.h )
  s.files += %w( include/grpc/impl/codegen/sync_posix.h )
  s.files += %w( include/grpc/impl/codegen/sync_windows.h )
+  s.files += %w( src/core/lib/gpr/arena.h )
+  s.files += %w( src/core/lib/gpr/env.h )
+  s.files += %w( src/core/lib/gpr/fork.h )
+  s.files += %w( src/core/lib/gpr/mpscq.h )
+  s.files += %w( src/core/lib/gpr/murmur_hash.h )
+  s.files += %w( src/core/lib/gpr/spinlock.h )
+  s.files += %w( src/core/lib/gpr/string.h )
+  s.files += %w( src/core/lib/gpr/string_windows.h )
+  s.files += %w( src/core/lib/gpr/thd_internal.h )
+  s.files += %w( src/core/lib/gpr/time_precise.h )
+  s.files += %w( src/core/lib/gpr/tmpfile.h )
+  s.files += %w( src/core/lib/gprpp/abstract.h )
+  s.files += %w( src/core/lib/gprpp/atomic.h )
+  s.files += %w( src/core/lib/gprpp/atomic_with_atm.h )
+  s.files += %w( src/core/lib/gprpp/atomic_with_std.h )
+  s.files += %w( src/core/lib/gprpp/manual_constructor.h )
+  s.files += %w( src/core/lib/gprpp/memory.h )
  s.files += %w( src/core/lib/profiling/timers.h )
-  s.files += %w( src/core/lib/support/abstract.h )
-  s.files += %w( src/core/lib/support/arena.h )
-  s.files += %w( src/core/lib/support/atomic.h )
-  s.files += %w( src/core/lib/support/atomic_with_atm.h )
-  s.files += %w( src/core/lib/support/atomic_with_std.h )
-  s.files += %w( src/core/lib/support/env.h )
-  s.files += %w( src/core/lib/support/fork.h )
-  s.files += %w( src/core/lib/support/manual_constructor.h )
-  s.files += %w( src/core/lib/support/memory.h )
-  s.files += %w( src/core/lib/support/mpscq.h )
-  s.files += %w( src/core/lib/support/murmur_hash.h )
-  s.files += %w( src/core/lib/support/spinlock.h )
-  s.files += %w( src/core/lib/support/string.h )
-  s.files += %w( src/core/lib/support/string_windows.h )
-  s.files += %w( src/core/lib/support/thd_internal.h )
-  s.files += %w( src/core/lib/support/time_precise.h )
-  s.files += %w( src/core/lib/support/tmpfile.h )
+  s.files += %w( src/core/lib/gpr/alloc.cc )
+  s.files += %w( src/core/lib/gpr/arena.cc )
+  s.files += %w( src/core/lib/gpr/atm.cc )
+  s.files += %w( src/core/lib/gpr/avl.cc )
+  s.files += %w( src/core/lib/gpr/cmdline.cc )
+  s.files += %w( src/core/lib/gpr/cpu_iphone.cc )
+  s.files += %w( src/core/lib/gpr/cpu_linux.cc )
+  s.files += %w( src/core/lib/gpr/cpu_posix.cc )
+  s.files += %w( src/core/lib/gpr/cpu_windows.cc )
+  s.files += %w( src/core/lib/gpr/env_linux.cc )
+  s.files += %w( src/core/lib/gpr/env_posix.cc )
+  s.files += %w( src/core/lib/gpr/env_windows.cc )
+  s.files += %w( src/core/lib/gpr/fork.cc )
+  s.files += %w( src/core/lib/gpr/host_port.cc )
+  s.files += %w( src/core/lib/gpr/log.cc )
+  s.files += %w( src/core/lib/gpr/log_android.cc )
+  s.files += %w( src/core/lib/gpr/log_linux.cc )
+  s.files += %w( src/core/lib/gpr/log_posix.cc )
+  s.files += %w( src/core/lib/gpr/log_windows.cc )
+  s.files += %w( src/core/lib/gpr/mpscq.cc )
+  s.files += %w( src/core/lib/gpr/murmur_hash.cc )
+  s.files += %w( src/core/lib/gpr/string.cc )
+  s.files += %w( src/core/lib/gpr/string_posix.cc )
+  s.files += %w( src/core/lib/gpr/string_util_windows.cc )
+  s.files += %w( src/core/lib/gpr/string_windows.cc )
+  s.files += %w( src/core/lib/gpr/subprocess_posix.cc )
+  s.files += %w( src/core/lib/gpr/subprocess_windows.cc )
+  s.files += %w( src/core/lib/gpr/sync.cc )
+  s.files += %w( src/core/lib/gpr/sync_posix.cc )
+  s.files += %w( src/core/lib/gpr/sync_windows.cc )
+  s.files += %w( src/core/lib/gpr/thd.cc )
+  s.files += %w( src/core/lib/gpr/thd_posix.cc )
+  s.files += %w( src/core/lib/gpr/thd_windows.cc )
+  s.files += %w( src/core/lib/gpr/time.cc )
+  s.files += %w( src/core/lib/gpr/time_posix.cc )
+  s.files += %w( src/core/lib/gpr/time_precise.cc )
+  s.files += %w( src/core/lib/gpr/time_windows.cc )
+  s.files += %w( src/core/lib/gpr/tls_pthread.cc )
+  s.files += %w( src/core/lib/gpr/tmpfile_msys.cc )
+  s.files += %w( src/core/lib/gpr/tmpfile_posix.cc )
+  s.files += %w( src/core/lib/gpr/tmpfile_windows.cc )
+  s.files += %w( src/core/lib/gpr/wrap_memcpy.cc )
  s.files += %w( src/core/lib/profiling/basic_timers.cc )
  s.files += %w( src/core/lib/profiling/stap_timers.cc )
-  s.files += %w( src/core/lib/support/alloc.cc )
-  s.files += %w( src/core/lib/support/arena.cc )
-  s.files += %w( src/core/lib/support/atm.cc )
-  s.files += %w( src/core/lib/support/avl.cc )
-  s.files += %w( src/core/lib/support/cmdline.cc )
-  s.files += %w( src/core/lib/support/cpu_iphone.cc )
-  s.files += %w( src/core/lib/support/cpu_linux.cc )
-  s.files += %w( src/core/lib/support/cpu_posix.cc )
-  s.files += %w( src/core/lib/support/cpu_windows.cc )
-  s.files += %w( src/core/lib/support/env_linux.cc )
-  s.files += %w( src/core/lib/support/env_posix.cc )
-  s.files += %w( src/core/lib/support/env_windows.cc )
-  s.files += %w( src/core/lib/support/fork.cc )
-  s.files += %w( src/core/lib/support/host_port.cc )
-  s.files += %w( src/core/lib/support/log.cc )
-  s.files += %w( src/core/lib/support/log_android.cc )
-  s.files += %w( src/core/lib/support/log_linux.cc )
-  s.files += %w( src/core/lib/support/log_posix.cc )
-  s.files += %w( src/core/lib/support/log_windows.cc )
-  s.files += %w( src/core/lib/support/mpscq.cc )
-  s.files += %w( src/core/lib/support/murmur_hash.cc )
-  s.files += %w( src/core/lib/support/string.cc )
-  s.files += %w( src/core/lib/support/string_posix.cc )
-  s.files += %w( src/core/lib/support/string_util_windows.cc )
-  s.files += %w( src/core/lib/support/string_windows.cc )
-  s.files += %w( src/core/lib/support/subprocess_posix.cc )
-  s.files += %w( src/core/lib/support/subprocess_windows.cc )
-  s.files += %w( src/core/lib/support/sync.cc )
-  s.files += %w( src/core/lib/support/sync_posix.cc )
-  s.files += %w( src/core/lib/support/sync_windows.cc )
-  s.files += %w( src/core/lib/support/thd.cc )
-  s.files += %w( src/core/lib/support/thd_posix.cc )
-  s.files += %w( src/core/lib/support/thd_windows.cc )
-  s.files += %w( src/core/lib/support/time.cc )
-  s.files += %w( src/core/lib/support/time_posix.cc )
-  s.files += %w( src/core/lib/support/time_precise.cc )
-  s.files += %w( src/core/lib/support/time_windows.cc )
-  s.files += %w( src/core/lib/support/tls_pthread.cc )
-  s.files += %w( src/core/lib/support/tmpfile_msys.cc )
-  s.files += %w( src/core/lib/support/tmpfile_posix.cc )
-  s.files += %w( src/core/lib/support/tmpfile_windows.cc )
-  s.files += %w( src/core/lib/support/wrap_memcpy.cc )
  s.files += %w( include/grpc/impl/codegen/byte_buffer.h )
  s.files += %w( include/grpc/impl/codegen/byte_buffer_reader.h )
  s.files += %w( include/grpc/impl/codegen/compression_types.h )
  s.files += %w( include/grpc/impl/codegen/connectivity_state.h )
-  s.files += %w( include/grpc/impl/codegen/exec_ctx_fwd.h )
  s.files += %w( include/grpc/impl/codegen/grpc_types.h )
  s.files += %w( include/grpc/impl/codegen/propagation_bits.h )
  s.files += %w( include/grpc/impl/codegen/slice.h )
@ -271,6 +270,11 @@ Gem::Specification.new do |s|
  s.files += %w( src/core/lib/compression/stream_compression_identity.h )
  s.files += %w( src/core/lib/debug/stats.h )
  s.files += %w( src/core/lib/debug/stats_data.h )
+  s.files += %w( src/core/lib/gprpp/debug_location.h )
+  s.files += %w( src/core/lib/gprpp/inlined_vector.h )
+  s.files += %w( src/core/lib/gprpp/orphanable.h )
+  s.files += %w( src/core/lib/gprpp/ref_counted.h )
+  s.files += %w( src/core/lib/gprpp/ref_counted_ptr.h )
  s.files += %w( src/core/lib/http/format_request.h )
  s.files += %w( src/core/lib/http/httpcli.h )
  s.files += %w( src/core/lib/http/parser.h )
@ -346,9 +350,6 @@ Gem::Specification.new do |s|
  s.files += %w( src/core/lib/slice/slice_hash_table.h )
  s.files += %w( src/core/lib/slice/slice_internal.h )
  s.files += %w( src/core/lib/slice/slice_string_helpers.h )
-  s.files += %w( src/core/lib/support/debug_location.h )
-  s.files += %w( src/core/lib/support/ref_counted.h )
-  s.files += %w( src/core/lib/support/ref_counted_ptr.h )
  s.files += %w( src/core/lib/surface/alarm_internal.h )
  s.files += %w( src/core/lib/surface/api_trace.h )
  s.files += %w( src/core/lib/surface/call.h )
--- a/grpc.gyp
+++ b/grpc.gyp
@ -57,6 +57,7 @@
      '-Wno-long-long',
      '-Wno-unused-parameter',
      '-DOSATOMIC_USE_INLINED=1',
+      '-Wno-deprecated-declarations',
    ],
    'ldflags': [
      '-g',
@ -134,6 +135,7 @@
            '-Wno-long-long',
            '-Wno-unused-parameter',
            '-DOSATOMIC_USE_INLINED=1',
+            '-Wno-deprecated-declarations',
          ],
          'OTHER_CPLUSPLUSFLAGS': [
            '-g',
@ -143,6 +145,7 @@
            '-Wno-long-long',
            '-Wno-unused-parameter',
            '-DOSATOMIC_USE_INLINED=1',
+            '-Wno-deprecated-declarations',
            '-stdlib=libc++',
            '-std=c++11',
            '-Wno-error=deprecated-declarations'
@ -158,50 +161,50 @@
      'dependencies': [
      ],
      'sources': [
+        'src/core/lib/gpr/alloc.cc',
+        'src/core/lib/gpr/arena.cc',
+        'src/core/lib/gpr/atm.cc',
+        'src/core/lib/gpr/avl.cc',
+        'src/core/lib/gpr/cmdline.cc',
+        'src/core/lib/gpr/cpu_iphone.cc',
+        'src/core/lib/gpr/cpu_linux.cc',
+        'src/core/lib/gpr/cpu_posix.cc',
+        'src/core/lib/gpr/cpu_windows.cc',
+        'src/core/lib/gpr/env_linux.cc',
+        'src/core/lib/gpr/env_posix.cc',
+        'src/core/lib/gpr/env_windows.cc',
+        'src/core/lib/gpr/fork.cc',
+        'src/core/lib/gpr/host_port.cc',
+        'src/core/lib/gpr/log.cc',
+        'src/core/lib/gpr/log_android.cc',
+        'src/core/lib/gpr/log_linux.cc',
+        'src/core/lib/gpr/log_posix.cc',
+        'src/core/lib/gpr/log_windows.cc',
+        'src/core/lib/gpr/mpscq.cc',
+        'src/core/lib/gpr/murmur_hash.cc',
+        'src/core/lib/gpr/string.cc',
+        'src/core/lib/gpr/string_posix.cc',
+        'src/core/lib/gpr/string_util_windows.cc',
+        'src/core/lib/gpr/string_windows.cc',
+        'src/core/lib/gpr/subprocess_posix.cc',
+        'src/core/lib/gpr/subprocess_windows.cc',
+        'src/core/lib/gpr/sync.cc',
+        'src/core/lib/gpr/sync_posix.cc',
+        'src/core/lib/gpr/sync_windows.cc',
+        'src/core/lib/gpr/thd.cc',
+        'src/core/lib/gpr/thd_posix.cc',
+        'src/core/lib/gpr/thd_windows.cc',
+        'src/core/lib/gpr/time.cc',
+        'src/core/lib/gpr/time_posix.cc',
+        'src/core/lib/gpr/time_precise.cc',
+        'src/core/lib/gpr/time_windows.cc',
+        'src/core/lib/gpr/tls_pthread.cc',
+        'src/core/lib/gpr/tmpfile_msys.cc',
+        'src/core/lib/gpr/tmpfile_posix.cc',
+        'src/core/lib/gpr/tmpfile_windows.cc',
+        'src/core/lib/gpr/wrap_memcpy.cc',
        'src/core/lib/profiling/basic_timers.cc',
        'src/core/lib/profiling/stap_timers.cc',
-        'src/core/lib/support/alloc.cc',
-        'src/core/lib/support/arena.cc',
-        'src/core/lib/support/atm.cc',
-        'src/core/lib/support/avl.cc',
-        'src/core/lib/support/cmdline.cc',
-        'src/core/lib/support/cpu_iphone.cc',
-        'src/core/lib/support/cpu_linux.cc',
-        'src/core/lib/support/cpu_posix.cc',
-        'src/core/lib/support/cpu_windows.cc',
-        'src/core/lib/support/env_linux.cc',
-        'src/core/lib/support/env_posix.cc',
-        'src/core/lib/support/env_windows.cc',
-        'src/core/lib/support/fork.cc',
-        'src/core/lib/support/host_port.cc',
-        'src/core/lib/support/log.cc',
-        'src/core/lib/support/log_android.cc',
-        'src/core/lib/support/log_linux.cc',
-        'src/core/lib/support/log_posix.cc',
-        'src/core/lib/support/log_windows.cc',
-        'src/core/lib/support/mpscq.cc',
-        'src/core/lib/support/murmur_hash.cc',
-        'src/core/lib/support/string.cc',
-        'src/core/lib/support/string_posix.cc',
-        'src/core/lib/support/string_util_windows.cc',
-        'src/core/lib/support/string_windows.cc',
-        'src/core/lib/support/subprocess_posix.cc',
-        'src/core/lib/support/subprocess_windows.cc',
-        'src/core/lib/support/sync.cc',
-        'src/core/lib/support/sync_posix.cc',
-        'src/core/lib/support/sync_windows.cc',
-        'src/core/lib/support/thd.cc',
-        'src/core/lib/support/thd_posix.cc',
-        'src/core/lib/support/thd_windows.cc',
-        'src/core/lib/support/time.cc',
-        'src/core/lib/support/time_posix.cc',
-        'src/core/lib/support/time_precise.cc',
-        'src/core/lib/support/time_windows.cc',
-        'src/core/lib/support/tls_pthread.cc',
-        'src/core/lib/support/tmpfile_msys.cc',
-        'src/core/lib/support/tmpfile_posix.cc',
-        'src/core/lib/support/tmpfile_windows.cc',
-        'src/core/lib/support/wrap_memcpy.cc',
      ],
    },
    {
@ -2378,6 +2381,7 @@
        'test/core/end2end/tests/filter_call_init_fails.cc',
        'test/core/end2end/tests/filter_causes_close.cc',
        'test/core/end2end/tests/filter_latency.cc',
+        'test/core/end2end/tests/filter_status_code.cc',
        'test/core/end2end/tests/graceful_server_shutdown.cc',
        'test/core/end2end/tests/high_initial_seqno.cc',
        'test/core/end2end/tests/hpack_size.cc',
@ -2450,6 +2454,7 @@
        'test/core/end2end/tests/filter_call_init_fails.cc',
        'test/core/end2end/tests/filter_causes_close.cc',
        'test/core/end2end/tests/filter_latency.cc',
+        'test/core/end2end/tests/filter_status_code.cc',
        'test/core/end2end/tests/graceful_server_shutdown.cc',
        'test/core/end2end/tests/high_initial_seqno.cc',
        'test/core/end2end/tests/hpack_size.cc',
--- a/include/grpc++/impl/codegen/method_handler_impl.h
+++ b/include/grpc++/impl/codegen/method_handler_impl.h
@ -27,6 +27,27 @@
 namespace grpc {

 namespace internal {
+
+// Invoke the method handler, fill in the status, and
+// return whether or not we finished safely (without an exception).
+// Note that exception handling is 0-cost in most compiler/library
+// implementations (except when an exception is actually thrown),
+// so this process doesn't require additional overhead in the common case.
+// Additionally, we don't need to return if we caught an exception or not;
+// the handling is the same in either case.
+template <class Callable>
+Status CatchingFunctionHandler(Callable&& handler) {
+#if GRPC_ALLOW_EXCEPTIONS
+  try {
+    return handler();
+  } catch (...) {
+    return Status(StatusCode::UNKNOWN, "Unexpected error in RPC handling");
+  }
+#else   // GRPC_ALLOW_EXCEPTIONS
+  return handler();
+#endif  // GRPC_ALLOW_EXCEPTIONS
+}
+
 /// A wrapper class of an application provided rpc method handler.
 template <class ServiceType, class RequestType, class ResponseType>
 class RpcMethodHandler : public MethodHandler {
@ -43,7 +64,9 @@ class RpcMethodHandler : public MethodHandler {
        param.request.bbuf_ptr(), &req);
    ResponseType rsp;
    if (status.ok()) {
-      status = func_(service_, param.server_context, &req, &rsp);
+      status = CatchingFunctionHandler([this, &param, &req, &rsp] {
+        return func_(service_, param.server_context, &req, &rsp);
+      });
    }

    GPR_CODEGEN_ASSERT(!param.server_context->sent_initial_metadata_);
@ -86,7 +109,9 @@ class ClientStreamingHandler : public MethodHandler {
  void RunHandler(const HandlerParameter& param) final {
    ServerReader<RequestType> reader(param.call, param.server_context);
    ResponseType rsp;
-    Status status = func_(service_, param.server_context, &reader, &rsp);
+    Status status = CatchingFunctionHandler([this, &param, &reader, &rsp] {
+      return func_(service_, param.server_context, &reader, &rsp);
+    });

    GPR_CODEGEN_ASSERT(!param.server_context->sent_initial_metadata_);
    CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
@ -130,7 +155,9 @@ class ServerStreamingHandler : public MethodHandler {

    if (status.ok()) {
      ServerWriter<ResponseType> writer(param.call, param.server_context);
-      status = func_(service_, param.server_context, &req, &writer);
+      status = CatchingFunctionHandler([this, &param, &req, &writer] {
+        return func_(service_, param.server_context, &req, &writer);
+      });
    }

    CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> ops;
@ -172,7 +199,9 @@ class TemplatedBidiStreamingHandler : public MethodHandler {

  void RunHandler(const HandlerParameter& param) final {
    Streamer stream(param.call, param.server_context);
-    Status status = func_(param.server_context, &stream);
+    Status status = CatchingFunctionHandler([this, &param, &stream] {
+      return func_(param.server_context, &stream);
+    });

    CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> ops;
    if (!param.server_context->sent_initial_metadata_) {
--- a/include/grpc/impl/codegen/exec_ctx_fwd.h
+++ b/include/grpc/impl/codegen/exec_ctx_fwd.h
@ -1,26 +0,0 @@
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-#ifndef GRPC_IMPL_CODEGEN_EXEC_CTX_FWD_H
-#define GRPC_IMPL_CODEGEN_EXEC_CTX_FWD_H
-
-/* forward declaration for exec_ctx.h */
-struct grpc_exec_ctx;
-typedef struct grpc_exec_ctx grpc_exec_ctx;
-
-#endif /* GRPC_IMPL_CODEGEN_EXEC_CTX_FWD_H */
--- a/include/grpc/impl/codegen/grpc_types.h
+++ b/include/grpc/impl/codegen/grpc_types.h
@ -22,7 +22,6 @@
 #include <grpc/impl/codegen/port_platform.h>

 #include <grpc/impl/codegen/compression_types.h>
-#include <grpc/impl/codegen/exec_ctx_fwd.h>
 #include <grpc/impl/codegen/gpr_types.h>
 #include <grpc/impl/codegen/slice.h>
 #include <grpc/impl/codegen/status.h>
--- a/include/grpc/impl/codegen/port_platform.h
+++ b/include/grpc/impl/codegen/port_platform.h
@ -195,12 +195,25 @@
 #define GPR_PTHREAD_TLS 1
 #else /* __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_7 */
 #define GPR_CPU_POSIX 1
+/* TODO(vjpai): there is a reported issue in bazel build for Mac where __thread
+   in a header is currently not working (bazelbuild/bazel#4341). Remove
+   the following conditional and use GPR_GCC_TLS when that is fixed */
+#ifndef GRPC_BAZEL_BUILD
 #define GPR_GCC_TLS 1
+#else /* GRPC_BAZEL_BUILD */
+#define GPR_PTHREAD_TLS 1
+#endif /* GRPC_BAZEL_BUILD */
 #define GPR_APPLE_PTHREAD_NAME 1
 #endif
 #else /* __MAC_OS_X_VERSION_MIN_REQUIRED */
 #define GPR_CPU_POSIX 1
+/* TODO(vjpai): Remove the following conditional and use only GPR_GCC_TLS
+   when bazelbuild/bazel#4341 is fixed */
+#ifndef GRPC_BAZEL_BUILD
 #define GPR_GCC_TLS 1
+#else /* GRPC_BAZEL_BUILD */
+#define GPR_PTHREAD_TLS 1
+#endif /* GRPC_BAZEL_BUILD */
 #endif
 #define GPR_POSIX_CRASH_HANDLER 1
 #endif
@ -421,6 +434,14 @@ typedef unsigned __int64 uint64_t;
 #endif
 #endif

+#ifndef GRPC_UNUSED
+#if defined(__GNUC__) && !defined(__MINGW32__)
+#define GRPC_UNUSED __attribute__((unused))
+#else
+#define GRPC_UNUSED
+#endif
+#endif
+
 #ifndef GPR_PRINT_FORMAT_CHECK
 #ifdef __GNUC__
 #define GPR_PRINT_FORMAT_CHECK(FORMAT_STR, ARGS) \
@ -464,6 +485,21 @@ typedef unsigned __int64 uint64_t;
 #endif /* GPR_ATTRIBUTE_NO_TSAN (2) */
 #endif /* GPR_ATTRIBUTE_NO_TSAN (1) */

+/* GRPC_ALLOW_EXCEPTIONS should be 0 or 1 if exceptions are allowed or not */
+#ifndef GRPC_ALLOW_EXCEPTIONS
+/* If not already set, set to 1 on Windows (style guide standard) but to
+ * 0 on non-Windows platforms unless the compiler defines __EXCEPTIONS */
+#ifdef GPR_WINDOWS
+#define GRPC_ALLOW_EXCEPTIONS 1
+#else /* GPR_WINDOWS */
+#ifdef __EXCEPTIONS
+#define GRPC_ALLOW_EXCEPTIONS 1
+#else /* __EXCEPTIONS */
+#define GRPC_ALLOW_EXCEPTIONS 0
+#endif /* __EXCEPTIONS */
+#endif /* __GPR_WINDOWS */
+#endif /* GRPC_ALLOW_EXCEPTIONS */
+
 #ifndef __STDC_FORMAT_MACROS
 #define __STDC_FORMAT_MACROS
 #endif
--- a/include/grpc/impl/codegen/slice.h
+++ b/include/grpc/impl/codegen/slice.h
@ -23,7 +23,6 @@

 #include <stddef.h>

-#include <grpc/impl/codegen/exec_ctx_fwd.h>
 #include <grpc/impl/codegen/gpr_slice.h>

 typedef struct grpc_slice grpc_slice;
--- a/include/grpc/module.modulemap
+++ b/include/grpc/module.modulemap
@ -30,7 +30,6 @@ framework module grpc {
  header "impl/codegen/byte_buffer_reader.h"
  header "impl/codegen/compression_types.h"
  header "impl/codegen/connectivity_state.h"
-  header "impl/codegen/exec_ctx_fwd.h"
  header "impl/codegen/grpc_types.h"
  header "impl/codegen/propagation_bits.h"
  header "impl/codegen/slice.h"
--- a/package.xml
+++ b/package.xml
@ -13,8 +13,8 @@
 <date>2017-08-24</date>
 <time>16:06:07</time>
 <version>
-  <release>1.9.0dev</release>
-  <api>1.9.0dev</api>
+  <release>1.10.0dev</release>
+  <api>1.10.0dev</api>
 </version>
 <stability>
  <release>beta</release>
@ -95,73 +95,72 @@
    <file baseinstalldir="/" name="include/grpc/impl/codegen/sync_generic.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/sync_posix.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/sync_windows.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/arena.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/env.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/fork.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/mpscq.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/murmur_hash.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/spinlock.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/string.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/string_windows.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/thd_internal.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/time_precise.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/tmpfile.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/abstract.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/atomic.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/atomic_with_atm.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/atomic_with_std.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/manual_constructor.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/memory.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/profiling/timers.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/abstract.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/arena.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/atomic.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/atomic_with_atm.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/atomic_with_std.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/env.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/fork.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/manual_constructor.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/memory.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/mpscq.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/murmur_hash.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/spinlock.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/string.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/string_windows.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/thd_internal.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/time_precise.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/tmpfile.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/alloc.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/arena.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/atm.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/avl.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/cmdline.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/cpu_iphone.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/cpu_linux.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/cpu_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/cpu_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/env_linux.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/env_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/env_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/fork.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/host_port.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/log.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/log_android.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/log_linux.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/log_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/log_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/mpscq.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/murmur_hash.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/string.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/string_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/string_util_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/string_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/subprocess_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/subprocess_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/sync.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/sync_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/sync_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/thd.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/thd_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/thd_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/time.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/time_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/time_precise.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/time_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/tls_pthread.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/tmpfile_msys.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/tmpfile_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/tmpfile_windows.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gpr/wrap_memcpy.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/profiling/basic_timers.cc" role="src" />
    <file baseinstalldir="/" name="src/core/lib/profiling/stap_timers.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/alloc.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/arena.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/atm.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/avl.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/cmdline.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/cpu_iphone.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/cpu_linux.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/cpu_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/cpu_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/env_linux.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/env_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/env_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/fork.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/host_port.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/log.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/log_android.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/log_linux.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/log_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/log_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/mpscq.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/murmur_hash.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/string.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/string_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/string_util_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/string_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/subprocess_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/subprocess_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/sync.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/sync_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/sync_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/thd.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/thd_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/thd_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/time.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/time_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/time_precise.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/time_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/tls_pthread.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/tmpfile_msys.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/tmpfile_posix.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/tmpfile_windows.cc" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/wrap_memcpy.cc" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/byte_buffer.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/byte_buffer_reader.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/compression_types.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/connectivity_state.h" role="src" />
-    <file baseinstalldir="/" name="include/grpc/impl/codegen/exec_ctx_fwd.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/grpc_types.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/propagation_bits.h" role="src" />
    <file baseinstalldir="/" name="include/grpc/impl/codegen/slice.h" role="src" />
@ -283,6 +282,11 @@
    <file baseinstalldir="/" name="src/core/lib/compression/stream_compression_identity.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/debug/stats.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/debug/stats_data.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/debug_location.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/inlined_vector.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/orphanable.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/ref_counted.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/gprpp/ref_counted_ptr.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/http/format_request.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/http/httpcli.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/http/parser.h" role="src" />
@ -358,9 +362,6 @@
    <file baseinstalldir="/" name="src/core/lib/slice/slice_hash_table.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/slice/slice_internal.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/slice/slice_string_helpers.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/debug_location.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/ref_counted.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/support/ref_counted_ptr.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/surface/alarm_internal.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/surface/api_trace.h" role="src" />
    <file baseinstalldir="/" name="src/core/lib/surface/call.h" role="src" />
--- a/src/core/ext/filters/client_channel/OWNERS
+++ b/src/core/ext/filters/client_channel/OWNERS
@ -1,4 +1,4 @@
 set noparent
@markdroth
@dgquintas
-@ctiller
+@a11r
--- a/src/core/ext/filters/client_channel/backup_poller.cc
+++ b/src/core/ext/filters/client_channel/backup_poller.cc
@ -23,17 +23,18 @@
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 #include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/iomgr/pollset.h"
 #include "src/core/lib/iomgr/timer.h"
-#include "src/core/lib/support/env.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/surface/completion_queue.h"

 #define DEFAULT_POLL_INTERVAL_MS 5000

-typedef struct backup_poller {
+namespace {
+struct backup_poller {
  grpc_timer polling_timer;
  grpc_closure run_poller_closure;
  grpc_closure shutdown_closure;
@ -42,7 +43,8 @@ typedef struct backup_poller {
  bool shutting_down;     // guarded by pollset_mu
  gpr_refcount refs;
  gpr_refcount shutdown_refs;
-} backup_poller;
+};
+}  // namespace

 static gpr_once g_once = GPR_ONCE_INIT;
 static gpr_mu g_poller_mu;
--- a/src/core/ext/filters/client_channel/channel_connectivity.cc
+++ b/src/core/ext/filters/client_channel/channel_connectivity.cc
@ -58,7 +58,8 @@ typedef enum {
  CALLING_BACK_AND_FINISHED,
 } callback_phase;

-typedef struct {
+namespace {
+struct state_watcher {
  gpr_mu mu;
  callback_phase phase;
  grpc_closure on_complete;
@ -71,7 +72,8 @@ typedef struct {
  grpc_channel* channel;
  grpc_error* error;
  void* tag;
-} state_watcher;
+};
+}  // namespace

 static void delete_state_watcher(state_watcher* w) {
  grpc_channel_element* client_channel_elem = grpc_channel_stack_last_element(
--- a/src/core/ext/filters/client_channel/client_channel.cc
+++ b/src/core/ext/filters/client_channel/client_channel.cc
@ -41,12 +41,12 @@
 #include "src/core/ext/filters/deadline/deadline_filter.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/connected_channel.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/iomgr.h"
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/metadata.h"
@ -553,6 +553,7 @@ static void on_resolver_result_changed_locked(void* arg, grpc_error* error) {
      }
      grpc_pollset_set_del_pollset_set(chand->lb_policy->interested_parties,
                                       chand->interested_parties);
+      grpc_lb_policy_shutdown_locked(chand->lb_policy, new_lb_policy);
      GRPC_LB_POLICY_UNREF(chand->lb_policy, "channel");
    }
    chand->lb_policy = new_lb_policy;
@ -658,6 +659,7 @@ static void start_transport_op_locked(void* arg, grpc_error* error_ignored) {
      if (chand->lb_policy != nullptr) {
        grpc_pollset_set_del_pollset_set(chand->lb_policy->interested_parties,
                                         chand->interested_parties);
+        grpc_lb_policy_shutdown_locked(chand->lb_policy, nullptr);
        GRPC_LB_POLICY_UNREF(chand->lb_policy, "channel");
        chand->lb_policy = nullptr;
      }
@ -792,6 +794,7 @@ static void cc_destroy_channel_elem(grpc_channel_element* elem) {
  if (chand->lb_policy != nullptr) {
    grpc_pollset_set_del_pollset_set(chand->lb_policy->interested_parties,
                                     chand->interested_parties);
+    grpc_lb_policy_shutdown_locked(chand->lb_policy, nullptr);
    GRPC_LB_POLICY_UNREF(chand->lb_policy, "channel");
  }
  gpr_free(chand->info_lb_policy_name);
@ -852,12 +855,10 @@ typedef struct client_channel_call_data {
  grpc_subchannel_call* subchannel_call;
  grpc_error* error;

-  grpc_lb_policy* lb_policy;  // Holds ref while LB pick is pending.
+  grpc_lb_policy_pick_state pick;
  grpc_closure lb_pick_closure;
  grpc_closure lb_pick_cancel_closure;

-  grpc_connected_subchannel* connected_subchannel;
-  grpc_call_context_element subchannel_call_context[GRPC_CONTEXT_COUNT];
  grpc_polling_entity* pollent;

  grpc_transport_stream_op_batch* waiting_for_pick_batches[MAX_WAITING_BATCHES];
@ -866,8 +867,6 @@ typedef struct client_channel_call_data {

  grpc_transport_stream_op_batch* initial_metadata_batch;

-  grpc_linked_mdelem lb_token_mdelem;
-
  grpc_closure on_complete;
  grpc_closure* original_on_complete;
 } call_data;
@ -1004,17 +1003,17 @@ static void create_subchannel_call_locked(grpc_call_element* elem,
                                          grpc_error* error) {
  channel_data* chand = (channel_data*)elem->channel_data;
  call_data* calld = (call_data*)elem->call_data;
-  const grpc_connected_subchannel_call_args call_args = {
-      calld->pollent,                  // pollent
-      calld->path,                     // path
-      calld->call_start_time,          // start_time
-      calld->deadline,                 // deadline
-      calld->arena,                    // arena
-      calld->subchannel_call_context,  // context
-      calld->call_combiner             // call_combiner
+  const grpc_core::ConnectedSubchannel::CallArgs call_args = {
+      calld->pollent,                       // pollent
+      calld->path,                          // path
+      calld->call_start_time,               // start_time
+      calld->deadline,                      // deadline
+      calld->arena,                         // arena
+      calld->pick.subchannel_call_context,  // context
+      calld->call_combiner                  // call_combiner
  };
-  grpc_error* new_error = grpc_connected_subchannel_create_call(
-      calld->connected_subchannel, &call_args, &calld->subchannel_call);
+  grpc_error* new_error = calld->pick.connected_subchannel->CreateCall(
+      call_args, &calld->subchannel_call);
  if (grpc_client_channel_trace.enabled()) {
    gpr_log(GPR_DEBUG, "chand=%p calld=%p: create subchannel_call=%p: error=%s",
            chand, calld, calld->subchannel_call, grpc_error_string(new_error));
@ -1032,7 +1031,7 @@ static void create_subchannel_call_locked(grpc_call_element* elem,
 static void pick_done_locked(grpc_call_element* elem, grpc_error* error) {
  call_data* calld = (call_data*)elem->call_data;
  channel_data* chand = (channel_data*)elem->channel_data;
-  if (calld->connected_subchannel == nullptr) {
+  if (calld->pick.connected_subchannel == nullptr) {
    // Failed to create subchannel.
    GRPC_ERROR_UNREF(calld->error);
    calld->error = error == GRPC_ERROR_NONE
@ -1071,13 +1070,16 @@ static void pick_callback_cancel_locked(void* arg, grpc_error* error) {
  grpc_call_element* elem = (grpc_call_element*)arg;
  channel_data* chand = (channel_data*)elem->channel_data;
  call_data* calld = (call_data*)elem->call_data;
-  if (calld->lb_policy != nullptr) {
+  // Note: chand->lb_policy may have changed since we started our pick,
+  // in which case we will be cancelling the pick on a policy other than
+  // the one we started it on.  However, this will just be a no-op.
+  if (error != GRPC_ERROR_NONE && chand->lb_policy != nullptr) {
    if (grpc_client_channel_trace.enabled()) {
      gpr_log(GPR_DEBUG, "chand=%p calld=%p: cancelling pick from LB policy %p",
-              chand, calld, calld->lb_policy);
+              chand, calld, chand->lb_policy);
    }
-    grpc_lb_policy_cancel_pick_locked(
-        calld->lb_policy, &calld->connected_subchannel, GRPC_ERROR_REF(error));
+    grpc_lb_policy_cancel_pick_locked(chand->lb_policy, &calld->pick,
+                                      GRPC_ERROR_REF(error));
  }
  GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback_cancel");
 }
@ -1092,9 +1094,6 @@ static void pick_callback_done_locked(void* arg, grpc_error* error) {
    gpr_log(GPR_DEBUG, "chand=%p calld=%p: pick completed asynchronously",
            chand, calld);
  }
-  GPR_ASSERT(calld->lb_policy != nullptr);
-  GRPC_LB_POLICY_UNREF(calld->lb_policy, "pick_subchannel");
-  calld->lb_policy = nullptr;
  async_pick_done_locked(elem, GRPC_ERROR_REF(error));
 }

@ -1128,26 +1127,21 @@ static bool pick_callback_start_locked(grpc_call_element* elem) {
      initial_metadata_flags &= ~GRPC_INITIAL_METADATA_WAIT_FOR_READY;
    }
  }
-  const grpc_lb_policy_pick_args inputs = {
+  calld->pick.initial_metadata =
      calld->initial_metadata_batch->payload->send_initial_metadata
-          .send_initial_metadata,
-      initial_metadata_flags, &calld->lb_token_mdelem};
-  // Keep a ref to the LB policy in calld while the pick is pending.
-  GRPC_LB_POLICY_REF(chand->lb_policy, "pick_subchannel");
-  calld->lb_policy = chand->lb_policy;
+          .send_initial_metadata;
+  calld->pick.initial_metadata_flags = initial_metadata_flags;
  GRPC_CLOSURE_INIT(&calld->lb_pick_closure, pick_callback_done_locked, elem,
                    grpc_combiner_scheduler(chand->combiner));
-  const bool pick_done = grpc_lb_policy_pick_locked(
-      chand->lb_policy, &inputs, &calld->connected_subchannel,
-      calld->subchannel_call_context, nullptr, &calld->lb_pick_closure);
+  calld->pick.on_complete = &calld->lb_pick_closure;
+  const bool pick_done =
+      grpc_lb_policy_pick_locked(chand->lb_policy, &calld->pick);
  if (pick_done) {
    /* synchronous grpc_lb_policy_pick call. Unref the LB policy. */
    if (grpc_client_channel_trace.enabled()) {
      gpr_log(GPR_DEBUG, "chand=%p calld=%p: pick completed synchronously",
              chand, calld);
    }
-    GRPC_LB_POLICY_UNREF(calld->lb_policy, "pick_subchannel");
-    calld->lb_policy = nullptr;
  } else {
    GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback_cancel");
    grpc_call_combiner_set_notify_on_cancel(
@ -1289,7 +1283,7 @@ static void start_pick_locked(void* arg, grpc_error* ignored) {
  grpc_call_element* elem = (grpc_call_element*)arg;
  call_data* calld = (call_data*)elem->call_data;
  channel_data* chand = (channel_data*)elem->channel_data;
-  GPR_ASSERT(calld->connected_subchannel == nullptr);
+  GPR_ASSERT(calld->pick.connected_subchannel == nullptr);
  if (chand->lb_policy != nullptr) {
    // We already have an LB policy, so ask it for a pick.
    if (pick_callback_start_locked(elem)) {
@ -1467,15 +1461,14 @@ static void cc_destroy_call_elem(grpc_call_element* elem,
    GRPC_SUBCHANNEL_CALL_UNREF(calld->subchannel_call,
                               "client_channel_destroy_call");
  }
-  GPR_ASSERT(calld->lb_policy == nullptr);
  GPR_ASSERT(calld->waiting_for_pick_batches_count == 0);
-  if (calld->connected_subchannel != nullptr) {
-    GRPC_CONNECTED_SUBCHANNEL_UNREF(calld->connected_subchannel, "picked");
+  if (calld->pick.connected_subchannel != nullptr) {
+    calld->pick.connected_subchannel.reset();
  }
  for (size_t i = 0; i < GRPC_CONTEXT_COUNT; ++i) {
-    if (calld->subchannel_call_context[i].value != nullptr) {
-      calld->subchannel_call_context[i].destroy(
-          calld->subchannel_call_context[i].value);
+    if (calld->pick.subchannel_call_context[i].value != nullptr) {
+      calld->pick.subchannel_call_context[i].destroy(
+          calld->pick.subchannel_call_context[i].value);
    }
  }
  GRPC_CLOSURE_SCHED(then_schedule_closure, GRPC_ERROR_NONE);
--- a/src/core/ext/filters/client_channel/http_connect_handshaker.cc
+++ b/src/core/ext/filters/client_channel/http_connect_handshaker.cc
@ -30,11 +30,11 @@
 #include "src/core/ext/filters/client_channel/uri_parser.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/handshaker_registry.h"
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/http/format_request.h"
 #include "src/core/lib/http/parser.h"
 #include "src/core/lib/slice/slice_internal.h"
-#include "src/core/lib/support/env.h"
-#include "src/core/lib/support/string.h"

 typedef struct http_connect_handshaker {
  // Base class.  Must be first.
--- a/src/core/ext/filters/client_channel/http_proxy.cc
+++ b/src/core/ext/filters/client_channel/http_proxy.cc
@ -30,9 +30,9 @@
 #include "src/core/ext/filters/client_channel/proxy_mapper_registry.h"
 #include "src/core/ext/filters/client_channel/uri_parser.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/slice/b64.h"
-#include "src/core/lib/support/env.h"
-#include "src/core/lib/support/string.h"

 /**
 * Parses the 'http_proxy' env var and returns the proxy hostname to resolve or
--- a/src/core/ext/filters/client_channel/lb_policy.cc
+++ b/src/core/ext/filters/client_channel/lb_policy.cc
@ -19,8 +19,6 @@
 #include "src/core/ext/filters/client_channel/lb_policy.h"
 #include "src/core/lib/iomgr/combiner.h"

-#define WEAK_REF_BITS 16
-
 grpc_core::DebugOnlyTraceFlag grpc_trace_lb_policy_refcount(
    false, "lb_policy_refcount");

@ -28,91 +26,60 @@ void grpc_lb_policy_init(grpc_lb_policy* policy,
                         const grpc_lb_policy_vtable* vtable,
                         grpc_combiner* combiner) {
  policy->vtable = vtable;
-  gpr_atm_no_barrier_store(&policy->ref_pair, 1 << WEAK_REF_BITS);
+  gpr_ref_init(&policy->refs, 1);
  policy->interested_parties = grpc_pollset_set_create();
  policy->combiner = GRPC_COMBINER_REF(combiner, "lb_policy");
 }

 #ifndef NDEBUG
-#define REF_FUNC_EXTRA_ARGS , const char *file, int line, const char *reason
-#define REF_MUTATE_EXTRA_ARGS REF_FUNC_EXTRA_ARGS, const char* purpose
-#define REF_FUNC_PASS_ARGS(new_reason) , file, line, new_reason
-#define REF_MUTATE_PASS_ARGS(purpose) , file, line, reason, purpose
+void grpc_lb_policy_ref(grpc_lb_policy* lb_policy, const char* file, int line,
+                        const char* reason) {
+  if (grpc_trace_lb_policy_refcount.enabled()) {
+    gpr_atm old_refs = gpr_atm_no_barrier_load(&lb_policy->refs.count);
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "LB_POLICY:%p   ref %" PRIdPTR " -> %" PRIdPTR " %s", lb_policy,
+            old_refs, old_refs + 1, reason);
+  }
 #else
-#define REF_FUNC_EXTRA_ARGS
-#define REF_MUTATE_EXTRA_ARGS
-#define REF_FUNC_PASS_ARGS(new_reason)
-#define REF_MUTATE_PASS_ARGS(x)
+void grpc_lb_policy_ref(grpc_lb_policy* lb_policy) {
 #endif
+  gpr_ref(&lb_policy->refs);
+}

-static gpr_atm ref_mutate(grpc_lb_policy* c, gpr_atm delta,
-                          int barrier REF_MUTATE_EXTRA_ARGS) {
-  gpr_atm old_val = barrier ? gpr_atm_full_fetch_add(&c->ref_pair, delta)
-                            : gpr_atm_no_barrier_fetch_add(&c->ref_pair, delta);
 #ifndef NDEBUG
+void grpc_lb_policy_unref(grpc_lb_policy* lb_policy, const char* file, int line,
+                          const char* reason) {
  if (grpc_trace_lb_policy_refcount.enabled()) {
+    gpr_atm old_refs = gpr_atm_no_barrier_load(&lb_policy->refs.count);
    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
-            "LB_POLICY: %p %12s 0x%" PRIxPTR " -> 0x%" PRIxPTR " [%s]", c,
-            purpose, old_val, old_val + delta, reason);
+            "LB_POLICY:%p unref %" PRIdPTR " -> %" PRIdPTR " %s", lb_policy,
+            old_refs, old_refs - 1, reason);
  }
+#else
+void grpc_lb_policy_unref(grpc_lb_policy* lb_policy) {
 #endif
-  return old_val;
-}
-
-void grpc_lb_policy_ref(grpc_lb_policy* policy REF_FUNC_EXTRA_ARGS) {
-  ref_mutate(policy, 1 << WEAK_REF_BITS, 0 REF_MUTATE_PASS_ARGS("STRONG_REF"));
-}
-
-static void shutdown_locked(void* arg, grpc_error* error) {
-  grpc_lb_policy* policy = (grpc_lb_policy*)arg;
-  policy->vtable->shutdown_locked(policy);
-  GRPC_LB_POLICY_WEAK_UNREF(policy, "strong-unref");
-}
-
-void grpc_lb_policy_unref(grpc_lb_policy* policy REF_FUNC_EXTRA_ARGS) {
-  gpr_atm old_val =
-      ref_mutate(policy, (gpr_atm)1 - (gpr_atm)(1 << WEAK_REF_BITS),
-                 1 REF_MUTATE_PASS_ARGS("STRONG_UNREF"));
-  gpr_atm mask = ~(gpr_atm)((1 << WEAK_REF_BITS) - 1);
-  gpr_atm check = 1 << WEAK_REF_BITS;
-  if ((old_val & mask) == check) {
-    GRPC_CLOSURE_SCHED(
-        GRPC_CLOSURE_CREATE(shutdown_locked, policy,
-                            grpc_combiner_scheduler(policy->combiner)),
-        GRPC_ERROR_NONE);
-  } else {
-    grpc_lb_policy_weak_unref(policy REF_FUNC_PASS_ARGS("strong-unref"));
+  if (gpr_unref(&lb_policy->refs)) {
+    grpc_pollset_set_destroy(lb_policy->interested_parties);
+    grpc_combiner* combiner = lb_policy->combiner;
+    lb_policy->vtable->destroy(lb_policy);
+    GRPC_COMBINER_UNREF(combiner, "lb_policy");
  }
 }

-void grpc_lb_policy_weak_ref(grpc_lb_policy* policy REF_FUNC_EXTRA_ARGS) {
-  ref_mutate(policy, 1, 0 REF_MUTATE_PASS_ARGS("WEAK_REF"));
-}
-
-void grpc_lb_policy_weak_unref(grpc_lb_policy* policy REF_FUNC_EXTRA_ARGS) {
-  gpr_atm old_val =
-      ref_mutate(policy, -(gpr_atm)1, 1 REF_MUTATE_PASS_ARGS("WEAK_UNREF"));
-  if (old_val == 1) {
-    grpc_pollset_set_destroy(policy->interested_parties);
-    grpc_combiner* combiner = policy->combiner;
-    policy->vtable->destroy(policy);
-    GRPC_COMBINER_UNREF(combiner, "lb_policy");
-  }
+void grpc_lb_policy_shutdown_locked(grpc_lb_policy* policy,
+                                    grpc_lb_policy* new_policy) {
+  policy->vtable->shutdown_locked(policy, new_policy);
 }

 int grpc_lb_policy_pick_locked(grpc_lb_policy* policy,
-                               const grpc_lb_policy_pick_args* pick_args,
-                               grpc_connected_subchannel** target,
-                               grpc_call_context_element* context,
-                               void** user_data, grpc_closure* on_complete) {
-  return policy->vtable->pick_locked(policy, pick_args, target, context,
-                                     user_data, on_complete);
+                               grpc_lb_policy_pick_state* pick) {
+  return policy->vtable->pick_locked(policy, pick);
 }

 void grpc_lb_policy_cancel_pick_locked(grpc_lb_policy* policy,
-                                       grpc_connected_subchannel** target,
+                                       grpc_lb_policy_pick_state* pick,
                                       grpc_error* error) {
-  policy->vtable->cancel_pick_locked(policy, target, error);
+  policy->vtable->cancel_pick_locked(policy, pick, error);
 }

 void grpc_lb_policy_cancel_picks_locked(grpc_lb_policy* policy,
--- a/src/core/ext/filters/client_channel/lb_policy.h
+++ b/src/core/ext/filters/client_channel/lb_policy.h
@ -20,6 +20,7 @@
 #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_H

 #include "src/core/ext/filters/client_channel/subchannel.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/transport/connectivity_state.h"

@ -33,7 +34,7 @@ extern grpc_core::DebugOnlyTraceFlag grpc_trace_lb_policy_refcount;

 struct grpc_lb_policy {
  const grpc_lb_policy_vtable* vtable;
-  gpr_atm ref_pair;
+  gpr_refcount refs;
  /* owned pointer to interested parties in load balancing decisions */
  grpc_pollset_set* interested_parties;
  /* combiner under which lb_policy actions take place */
@ -42,32 +43,42 @@ struct grpc_lb_policy {
  grpc_closure* request_reresolution;
 };

-/** Extra arguments for an LB pick */
-typedef struct grpc_lb_policy_pick_args {
-  /** Initial metadata associated with the picking call. */
+/// State used for an LB pick.
+typedef struct grpc_lb_policy_pick_state {
+  /// Initial metadata associated with the picking call.
  grpc_metadata_batch* initial_metadata;
-  /** Bitmask used for selective cancelling. See \a
-   * grpc_lb_policy_cancel_picks() and \a GRPC_INITIAL_METADATA_* in
-   * grpc_types.h */
+  /// Bitmask used for selective cancelling. See \a
+  /// grpc_lb_policy_cancel_picks() and \a GRPC_INITIAL_METADATA_* in
+  /// grpc_types.h.
  uint32_t initial_metadata_flags;
-  /** Storage for LB token in \a initial_metadata, or NULL if not used */
-  grpc_linked_mdelem* lb_token_mdelem_storage;
-} grpc_lb_policy_pick_args;
+  /// Storage for LB token in \a initial_metadata, or NULL if not used.
+  grpc_linked_mdelem lb_token_mdelem_storage;
+  /// Closure to run when pick is complete, if not completed synchronously.
+  grpc_closure* on_complete;
+  /// Will be set to the selected subchannel, or nullptr on failure or when
+  /// the LB policy decides to drop the call.
+  grpc_core::RefCountedPtr<grpc_core::ConnectedSubchannel> connected_subchannel;
+  /// Will be populated with context to pass to the subchannel call, if needed.
+  grpc_call_context_element subchannel_call_context[GRPC_CONTEXT_COUNT];
+  /// Upon success, \a *user_data will be set to whatever opaque information
+  /// may need to be propagated from the LB policy, or NULL if not needed.
+  void** user_data;
+  /// Next pointer.  For internal use by LB policy.
+  struct grpc_lb_policy_pick_state* next;
+} grpc_lb_policy_pick_state;

 struct grpc_lb_policy_vtable {
  void (*destroy)(grpc_lb_policy* policy);
-  void (*shutdown_locked)(grpc_lb_policy* policy);
+
+  /// \see grpc_lb_policy_shutdown_locked().
+  void (*shutdown_locked)(grpc_lb_policy* policy, grpc_lb_policy* new_policy);

  /** \see grpc_lb_policy_pick */
-  int (*pick_locked)(grpc_lb_policy* policy,
-                     const grpc_lb_policy_pick_args* pick_args,
-                     grpc_connected_subchannel** target,
-                     grpc_call_context_element* context, void** user_data,
-                     grpc_closure* on_complete);
+  int (*pick_locked)(grpc_lb_policy* policy, grpc_lb_policy_pick_state* pick);

  /** \see grpc_lb_policy_cancel_pick */
  void (*cancel_pick_locked)(grpc_lb_policy* policy,
-                             grpc_connected_subchannel** target,
+                             grpc_lb_policy_pick_state* pick,
                             grpc_error* error);

  /** \see grpc_lb_policy_cancel_picks */
@ -103,37 +114,19 @@ struct grpc_lb_policy_vtable {
 };

 #ifndef NDEBUG
-
-/* Strong references: the policy will shutdown when they reach zero */
 #define GRPC_LB_POLICY_REF(p, r) \
  grpc_lb_policy_ref((p), __FILE__, __LINE__, (r))
 #define GRPC_LB_POLICY_UNREF(p, r) \
  grpc_lb_policy_unref((p), __FILE__, __LINE__, (r))
-
-/* Weak references: they don't prevent the shutdown of the LB policy. When no
- * strong references are left but there are still weak ones, shutdown is called.
- * Once the weak reference also reaches zero, the LB policy is destroyed. */
-#define GRPC_LB_POLICY_WEAK_REF(p, r) \
-  grpc_lb_policy_weak_ref((p), __FILE__, __LINE__, (r))
-#define GRPC_LB_POLICY_WEAK_UNREF(p, r) \
-  grpc_lb_policy_weak_unref((p), __FILE__, __LINE__, (r))
 void grpc_lb_policy_ref(grpc_lb_policy* policy, const char* file, int line,
                        const char* reason);
 void grpc_lb_policy_unref(grpc_lb_policy* policy, const char* file, int line,
                          const char* reason);
-void grpc_lb_policy_weak_ref(grpc_lb_policy* policy, const char* file, int line,
-                             const char* reason);
-void grpc_lb_policy_weak_unref(grpc_lb_policy* policy, const char* file,
-                               int line, const char* reason);
-#else
+#else  // !NDEBUG
 #define GRPC_LB_POLICY_REF(p, r) grpc_lb_policy_ref((p))
 #define GRPC_LB_POLICY_UNREF(p, r) grpc_lb_policy_unref((p))
-#define GRPC_LB_POLICY_WEAK_REF(p, r) grpc_lb_policy_weak_ref((p))
-#define GRPC_LB_POLICY_WEAK_UNREF(p, r) grpc_lb_policy_weak_unref((p))
 void grpc_lb_policy_ref(grpc_lb_policy* policy);
 void grpc_lb_policy_unref(grpc_lb_policy* policy);
-void grpc_lb_policy_weak_ref(grpc_lb_policy* policy);
-void grpc_lb_policy_weak_unref(grpc_lb_policy* policy);
 #endif

 /** called by concrete implementations to initialize the base struct */
@ -141,40 +134,37 @@ void grpc_lb_policy_init(grpc_lb_policy* policy,
                         const grpc_lb_policy_vtable* vtable,
                         grpc_combiner* combiner);

-/** Finds an appropriate subchannel for a call, based on \a pick_args.
-
-    \a target will be set to the selected subchannel, or NULL on failure
-    or when the LB policy decides to drop the call.
+/// Shuts down \a policy.
+/// If \a new_policy is non-null, any pending picks will be restarted
+/// on that policy; otherwise, they will be failed.
+void grpc_lb_policy_shutdown_locked(grpc_lb_policy* policy,
+                                    grpc_lb_policy* new_policy);

-    Upon success, \a user_data will be set to whatever opaque information
-    may need to be propagated from the LB policy, or NULL if not needed.
-    \a context will be populated with context to pass to the subchannel
-    call, if needed.
+/** Finds an appropriate subchannel for a call, based on data in \a pick.
+    \a pick must remain alive until the pick is complete.

    If the pick succeeds and a result is known immediately, a non-zero
-    value will be returned.  Otherwise, \a on_complete will be invoked
+    value will be returned.  Otherwise, \a pick->on_complete will be invoked
    once the pick is complete with its error argument set to indicate
    success or failure.

    Any IO should be done under the \a interested_parties \a grpc_pollset_set
    in the \a grpc_lb_policy struct. */
 int grpc_lb_policy_pick_locked(grpc_lb_policy* policy,
-                               const grpc_lb_policy_pick_args* pick_args,
-                               grpc_connected_subchannel** target,
-                               grpc_call_context_element* context,
-                               void** user_data, grpc_closure* on_complete);
+                               grpc_lb_policy_pick_state* pick);

-/** Perform a connected subchannel ping (see \a grpc_connected_subchannel_ping)
+/** Perform a connected subchannel ping (see \a
+   grpc_core::ConnectedSubchannel::Ping)
    against one of the connected subchannels managed by \a policy. */
 void grpc_lb_policy_ping_one_locked(grpc_lb_policy* policy,
                                    grpc_closure* on_initiate,
                                    grpc_closure* on_ack);

-/** Cancel picks for \a target.
+/** Cancel picks for \a pick.
    The \a on_complete callback of the pending picks will be invoked with \a
    *target set to NULL. */
 void grpc_lb_policy_cancel_pick_locked(grpc_lb_policy* policy,
-                                       grpc_connected_subchannel** target,
+                                       grpc_lb_policy_pick_state* pick,
                                       grpc_error* error);

 /** Cancel all pending picks for which their \a initial_metadata_flags (as given
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.cc
@ -32,7 +32,8 @@ static grpc_error* init_channel_elem(grpc_channel_element* elem,

 static void destroy_channel_elem(grpc_channel_element* elem) {}

-typedef struct {
+namespace {
+struct call_data {
  // Stats object to update.
  grpc_grpclb_client_stats* client_stats;
  // State for intercepting send_initial_metadata.
@ -43,7 +44,8 @@ typedef struct {
  grpc_closure recv_initial_metadata_ready;
  grpc_closure* original_recv_initial_metadata_ready;
  bool recv_initial_metadata_succeeded;
-} call_data;
+};
+}  // namespace

 static void on_complete_for_send(void* arg, grpc_error* error) {
  call_data* calld = (call_data*)arg;
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.cc
@ -22,8 +22,8 @@
 #include "src/core/ext/filters/client_channel/client_channel.h"
 #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
-#include "src/core/lib/support/string.h"

 grpc_channel* grpc_lb_policy_grpclb_create_lb_channel(
    const char* lb_service_target_addresses,
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel_secure.cc
@ -22,11 +22,11 @@
 #include "src/core/ext/filters/client_channel/client_channel.h"
 #include "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/security/credentials/credentials.h"
 #include "src/core/lib/security/transport/lb_targets_info.h"
 #include "src/core/lib/slice/slice_internal.h"
-#include "src/core/lib/support/string.h"

 grpc_channel* grpc_lb_policy_grpclb_create_lb_channel(
    const char* lb_service_target_addresses,
--- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
@ -31,13 +31,6 @@

 grpc_core::TraceFlag grpc_lb_pick_first_trace(false, "pick_first");

-typedef struct pending_pick {
-  struct pending_pick* next;
-  uint32_t initial_metadata_flags;
-  grpc_connected_subchannel** target;
-  grpc_closure* on_complete;
-} pending_pick;
-
 typedef struct {
  /** base policy: must be first */
  grpc_lb_policy base;
@ -52,7 +45,7 @@ typedef struct {
  /** are we shut down? */
  bool shutdown;
  /** list of picks that are waiting on connectivity */
-  pending_pick* pending_picks;
+  grpc_lb_policy_pick_state* pending_picks;
  /** our connectivity state tracker */
  grpc_connectivity_state_tracker state_tracker;
 } pick_first_lb_policy;
@ -70,19 +63,27 @@ static void pf_destroy(grpc_lb_policy* pol) {
  }
 }

-static void pf_shutdown_locked(grpc_lb_policy* pol) {
+static void pf_shutdown_locked(grpc_lb_policy* pol,
+                               grpc_lb_policy* new_policy) {
  pick_first_lb_policy* p = (pick_first_lb_policy*)pol;
  grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel shutdown");
  if (grpc_lb_pick_first_trace.enabled()) {
    gpr_log(GPR_DEBUG, "Pick First %p Shutting down", p);
  }
  p->shutdown = true;
-  pending_pick* pp;
-  while ((pp = p->pending_picks) != nullptr) {
-    p->pending_picks = pp->next;
-    *pp->target = nullptr;
-    GRPC_CLOSURE_SCHED(pp->on_complete, GRPC_ERROR_REF(error));
-    gpr_free(pp);
+  grpc_lb_policy_pick_state* pick;
+  while ((pick = p->pending_picks) != nullptr) {
+    p->pending_picks = pick->next;
+    if (new_policy != nullptr) {
+      // Hand off to new LB policy.
+      if (grpc_lb_policy_pick_locked(new_policy, pick)) {
+        // Synchronous return, schedule closure.
+        GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_NONE);
+      }
+    } else {
+      pick->connected_subchannel.reset();
+      GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_REF(error));
+    }
  }
  grpc_connectivity_state_set(&p->state_tracker, GRPC_CHANNEL_SHUTDOWN,
                              GRPC_ERROR_REF(error), "shutdown");
@ -102,19 +103,18 @@ static void pf_shutdown_locked(grpc_lb_policy* pol) {
 }

 static void pf_cancel_pick_locked(grpc_lb_policy* pol,
-                                  grpc_connected_subchannel** target,
+                                  grpc_lb_policy_pick_state* pick,
                                  grpc_error* error) {
  pick_first_lb_policy* p = (pick_first_lb_policy*)pol;
-  pending_pick* pp = p->pending_picks;
+  grpc_lb_policy_pick_state* pp = p->pending_picks;
  p->pending_picks = nullptr;
  while (pp != nullptr) {
-    pending_pick* next = pp->next;
-    if (pp->target == target) {
-      *target = nullptr;
-      GRPC_CLOSURE_SCHED(pp->on_complete,
+    grpc_lb_policy_pick_state* next = pp->next;
+    if (pp == pick) {
+      pick->connected_subchannel.reset();
+      GRPC_CLOSURE_SCHED(pick->on_complete,
                         GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                             "Pick Cancelled", &error, 1));
-      gpr_free(pp);
    } else {
      pp->next = p->pending_picks;
      p->pending_picks = pp;
@ -129,21 +129,20 @@ static void pf_cancel_picks_locked(grpc_lb_policy* pol,
                                   uint32_t initial_metadata_flags_eq,
                                   grpc_error* error) {
  pick_first_lb_policy* p = (pick_first_lb_policy*)pol;
-  pending_pick* pp = p->pending_picks;
+  grpc_lb_policy_pick_state* pick = p->pending_picks;
  p->pending_picks = nullptr;
-  while (pp != nullptr) {
-    pending_pick* next = pp->next;
-    if ((pp->initial_metadata_flags & initial_metadata_flags_mask) ==
+  while (pick != nullptr) {
+    grpc_lb_policy_pick_state* next = pick->next;
+    if ((pick->initial_metadata_flags & initial_metadata_flags_mask) ==
        initial_metadata_flags_eq) {
-      GRPC_CLOSURE_SCHED(pp->on_complete,
+      GRPC_CLOSURE_SCHED(pick->on_complete,
                         GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                             "Pick Cancelled", &error, 1));
-      gpr_free(pp);
    } else {
-      pp->next = p->pending_picks;
-      p->pending_picks = pp;
+      pick->next = p->pending_picks;
+      p->pending_picks = pick;
    }
-    pp = next;
+    pick = next;
  }
  GRPC_ERROR_UNREF(error);
 }
@ -173,27 +172,19 @@ static void pf_exit_idle_locked(grpc_lb_policy* pol) {
 }

 static int pf_pick_locked(grpc_lb_policy* pol,
-                          const grpc_lb_policy_pick_args* pick_args,
-                          grpc_connected_subchannel** target,
-                          grpc_call_context_element* context, void** user_data,
-                          grpc_closure* on_complete) {
+                          grpc_lb_policy_pick_state* pick) {
  pick_first_lb_policy* p = (pick_first_lb_policy*)pol;
  // If we have a selected subchannel already, return synchronously.
  if (p->selected != nullptr) {
-    *target = GRPC_CONNECTED_SUBCHANNEL_REF(p->selected->connected_subchannel,
-                                            "picked");
+    pick->connected_subchannel = p->selected->connected_subchannel;
    return 1;
  }
  // No subchannel selected yet, so handle asynchronously.
  if (!p->started_picking) {
    start_picking_locked(p);
  }
-  pending_pick* pp = (pending_pick*)gpr_malloc(sizeof(*pp));
-  pp->next = p->pending_picks;
-  pp->target = target;
-  pp->initial_metadata_flags = pick_args->initial_metadata_flags;
-  pp->on_complete = on_complete;
-  p->pending_picks = pp;
+  pick->next = p->pending_picks;
+  p->pending_picks = pick;
  return 0;
 }

@ -225,8 +216,7 @@ static void pf_ping_one_locked(grpc_lb_policy* pol, grpc_closure* on_initiate,
                               grpc_closure* on_ack) {
  pick_first_lb_policy* p = (pick_first_lb_policy*)pol;
  if (p->selected) {
-    grpc_connected_subchannel_ping(p->selected->connected_subchannel,
-                                   on_initiate, on_ack);
+    p->selected->connected_subchannel->Ping(on_initiate, on_ack);
  } else {
    GRPC_CLOSURE_SCHED(on_initiate,
                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
@ -305,8 +295,7 @@ static void pf_update_locked(grpc_lb_policy* policy,
                  subchannel_list->num_subchannels);
        }
        if (p->selected->connected_subchannel != nullptr) {
-          sd->connected_subchannel = GRPC_CONNECTED_SUBCHANNEL_REF(
-              p->selected->connected_subchannel, "pf_update_includes_selected");
+          sd->connected_subchannel = p->selected->connected_subchannel;
        }
        p->selected = sd;
        if (p->subchannel_list != nullptr) {
@ -418,8 +407,8 @@ static void pf_connectivity_changed_locked(void* arg, grpc_error* error) {
      // re-resolution is introduced. But we need to investigate whether we
      // really want to take any action instead of waiting for the selected
      // subchannel reconnecting.
-      if (sd->curr_connectivity_state == GRPC_CHANNEL_SHUTDOWN ||
-          sd->curr_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
+      GPR_ASSERT(sd->curr_connectivity_state != GRPC_CHANNEL_SHUTDOWN);
+      if (sd->curr_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
        // If the selected channel goes bad, request a re-resolution.
        grpc_connectivity_state_set(&p->state_tracker, GRPC_CHANNEL_IDLE,
                                    GRPC_ERROR_NONE,
@ -427,20 +416,19 @@ static void pf_connectivity_changed_locked(void* arg, grpc_error* error) {
        p->started_picking = false;
        grpc_lb_policy_try_reresolve(&p->base, &grpc_lb_pick_first_trace,
                                     GRPC_ERROR_NONE);
+        // in transient failure. Rely on re-resolution to recover.
+        p->selected = nullptr;
+        grpc_lb_subchannel_data_stop_connectivity_watch(sd);
+        grpc_lb_subchannel_list_unref_for_connectivity_watch(
+            sd->subchannel_list, "pf_selected_shutdown");
+        grpc_lb_subchannel_data_unref_subchannel(
+            sd, "pf_selected_shutdown");  // Unrefs connected subchannel
      } else {
        grpc_connectivity_state_set(&p->state_tracker,
                                    sd->curr_connectivity_state,
                                    GRPC_ERROR_REF(error), "selected_changed");
-      }
-      if (sd->curr_connectivity_state != GRPC_CHANNEL_SHUTDOWN) {
        // Renew notification.
        grpc_lb_subchannel_data_start_connectivity_watch(sd);
-      } else {
-        p->selected = nullptr;
-        grpc_lb_subchannel_data_stop_connectivity_watch(sd);
-        grpc_lb_subchannel_list_unref_for_connectivity_watch(
-            sd->subchannel_list, "pf_selected_shutdown");
-        grpc_lb_subchannel_data_unref_subchannel(sd, "pf_selected_shutdown");
      }
    }
    return;
@ -458,6 +446,8 @@ static void pf_connectivity_changed_locked(void* arg, grpc_error* error) {
    case GRPC_CHANNEL_READY: {
      // Case 2.  Promote p->latest_pending_subchannel_list to
      // p->subchannel_list.
+      sd->connected_subchannel =
+          grpc_subchannel_get_connected_subchannel(sd->subchannel);
      if (sd->subchannel_list == p->latest_pending_subchannel_list) {
        GPR_ASSERT(p->subchannel_list != nullptr);
        grpc_lb_subchannel_list_shutdown_and_unref(p->subchannel_list,
@ -468,9 +458,6 @@ static void pf_connectivity_changed_locked(void* arg, grpc_error* error) {
      // Cases 1 and 2.
      grpc_connectivity_state_set(&p->state_tracker, GRPC_CHANNEL_READY,
                                  GRPC_ERROR_NONE, "connecting_ready");
-      sd->connected_subchannel = GRPC_CONNECTED_SUBCHANNEL_REF(
-          grpc_subchannel_get_connected_subchannel(sd->subchannel),
-          "connected");
      p->selected = sd;
      if (grpc_lb_pick_first_trace.enabled()) {
        gpr_log(GPR_INFO, "Pick First %p selected subchannel %p", (void*)p,
@ -479,18 +466,16 @@ static void pf_connectivity_changed_locked(void* arg, grpc_error* error) {
      // Drop all other subchannels, since we are now connected.
      destroy_unselected_subchannels_locked(p);
      // Update any calls that were waiting for a pick.
-      pending_pick* pp;
-      while ((pp = p->pending_picks)) {
-        p->pending_picks = pp->next;
-        *pp->target = GRPC_CONNECTED_SUBCHANNEL_REF(
-            p->selected->connected_subchannel, "picked");
+      grpc_lb_policy_pick_state* pick;
+      while ((pick = p->pending_picks)) {
+        p->pending_picks = pick->next;
+        pick->connected_subchannel = p->selected->connected_subchannel;
        if (grpc_lb_pick_first_trace.enabled()) {
          gpr_log(GPR_INFO,
                  "Servicing pending pick with selected subchannel %p",
                  (void*)p->selected);
        }
-        GRPC_CLOSURE_SCHED(pp->on_complete, GRPC_ERROR_NONE);
-        gpr_free(pp);
+        GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_NONE);
      }
      // Renew notification.
      grpc_lb_subchannel_data_start_connectivity_watch(sd);
@ -529,39 +514,8 @@ static void pf_connectivity_changed_locked(void* arg, grpc_error* error) {
      grpc_lb_subchannel_data_start_connectivity_watch(sd);
      break;
    }
-    case GRPC_CHANNEL_SHUTDOWN: {
-      grpc_lb_subchannel_data_stop_connectivity_watch(sd);
-      grpc_lb_subchannel_data_unref_subchannel(sd, "pf_candidate_shutdown");
-      // Advance to next subchannel and check its state.
-      grpc_lb_subchannel_data* original_sd = sd;
-      do {
-        sd->subchannel_list->checking_subchannel =
-            (sd->subchannel_list->checking_subchannel + 1) %
-            sd->subchannel_list->num_subchannels;
-        sd = &sd->subchannel_list
-                  ->subchannels[sd->subchannel_list->checking_subchannel];
-      } while (sd->subchannel == nullptr && sd != original_sd);
-      if (sd == original_sd) {
-        grpc_lb_subchannel_list_unref_for_connectivity_watch(
-            sd->subchannel_list, "pf_exhausted_subchannels");
-        if (sd->subchannel_list == p->subchannel_list) {
-          grpc_connectivity_state_set(&p->state_tracker, GRPC_CHANNEL_IDLE,
-                                      GRPC_ERROR_NONE,
-                                      "exhausted_subchannels+reresolve");
-          p->started_picking = false;
-          grpc_lb_policy_try_reresolve(&p->base, &grpc_lb_pick_first_trace,
-                                       GRPC_ERROR_NONE);
-        }
-      } else {
-        if (sd->subchannel_list == p->subchannel_list) {
-          grpc_connectivity_state_set(
-              &p->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
-              GRPC_ERROR_REF(error), "subchannel_failed");
-        }
-        // Reuses the connectivity refs from the previous watch.
-        grpc_lb_subchannel_data_start_connectivity_watch(sd);
-      }
-    }
+    case GRPC_CHANNEL_SHUTDOWN:
+      GPR_UNREACHABLE_CODE(break);
  }
 }

--- a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc
@ -34,6 +34,7 @@
 #include "src/core/ext/filters/client_channel/subchannel_index.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/transport/connectivity_state.h"
@ -41,29 +42,6 @@

 grpc_core::TraceFlag grpc_lb_round_robin_trace(false, "round_robin");

-/** List of entities waiting for a pick.
- *
- * Once a pick is available, \a target is updated and \a on_complete called. */
-typedef struct pending_pick {
-  struct pending_pick* next;
-
-  /* output argument where to store the pick()ed user_data. It'll be NULL if no
-   * such data is present or there's an error (the definite test for errors is
-   * \a target being NULL). */
-  void** user_data;
-
-  /* bitmask passed to pick() and used for selective cancelling. See
-   * grpc_lb_policy_cancel_picks() */
-  uint32_t initial_metadata_flags;
-
-  /* output argument where to store the pick()ed connected subchannel, or NULL
-   * upon error. */
-  grpc_connected_subchannel** target;
-
-  /* to be invoked once the pick() has completed (regardless of success) */
-  grpc_closure* on_complete;
-} pending_pick;
-
 typedef struct round_robin_lb_policy {
  /** base policy: must be first */
  grpc_lb_policy base;
@ -75,7 +53,7 @@ typedef struct round_robin_lb_policy {
  /** are we shutting down? */
  bool shutdown;
  /** List of picks that are waiting on connectivity */
-  pending_pick* pending_picks;
+  grpc_lb_policy_pick_state* pending_picks;

  /** our connectivity state tracker */
  grpc_connectivity_state_tracker state_tracker;
@ -150,7 +128,7 @@ static void update_last_ready_subchannel_index_locked(round_robin_lb_policy* p,
            (void*)p, (unsigned long)last_ready_index,
            (void*)p->subchannel_list->subchannels[last_ready_index].subchannel,
            (void*)p->subchannel_list->subchannels[last_ready_index]
-                .connected_subchannel);
+                .connected_subchannel.get());
  }
 }

@ -167,19 +145,27 @@ static void rr_destroy(grpc_lb_policy* pol) {
  gpr_free(p);
 }

-static void rr_shutdown_locked(grpc_lb_policy* pol) {
+static void rr_shutdown_locked(grpc_lb_policy* pol,
+                               grpc_lb_policy* new_policy) {
  round_robin_lb_policy* p = (round_robin_lb_policy*)pol;
  grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Channel shutdown");
  if (grpc_lb_round_robin_trace.enabled()) {
    gpr_log(GPR_DEBUG, "[RR %p] Shutting down", p);
  }
  p->shutdown = true;
-  pending_pick* pp;
-  while ((pp = p->pending_picks) != nullptr) {
-    p->pending_picks = pp->next;
-    *pp->target = nullptr;
-    GRPC_CLOSURE_SCHED(pp->on_complete, GRPC_ERROR_REF(error));
-    gpr_free(pp);
+  grpc_lb_policy_pick_state* pick;
+  while ((pick = p->pending_picks) != nullptr) {
+    p->pending_picks = pick->next;
+    if (new_policy != nullptr) {
+      // Hand off to new LB policy.
+      if (grpc_lb_policy_pick_locked(new_policy, pick)) {
+        // Synchronous return; schedule callback.
+        GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_NONE);
+      }
+    } else {
+      pick->connected_subchannel.reset();
+      GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_REF(error));
+    }
  }
  grpc_connectivity_state_set(&p->state_tracker, GRPC_CHANNEL_SHUTDOWN,
                              GRPC_ERROR_REF(error), "rr_shutdown");
@ -199,19 +185,18 @@ static void rr_shutdown_locked(grpc_lb_policy* pol) {
 }

 static void rr_cancel_pick_locked(grpc_lb_policy* pol,
-                                  grpc_connected_subchannel** target,
+                                  grpc_lb_policy_pick_state* pick,
                                  grpc_error* error) {
  round_robin_lb_policy* p = (round_robin_lb_policy*)pol;
-  pending_pick* pp = p->pending_picks;
+  grpc_lb_policy_pick_state* pp = p->pending_picks;
  p->pending_picks = nullptr;
  while (pp != nullptr) {
-    pending_pick* next = pp->next;
-    if (pp->target == target) {
-      *target = nullptr;
-      GRPC_CLOSURE_SCHED(pp->on_complete,
+    grpc_lb_policy_pick_state* next = pp->next;
+    if (pp == pick) {
+      pick->connected_subchannel.reset();
+      GRPC_CLOSURE_SCHED(pick->on_complete,
                         GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                             "Pick cancelled", &error, 1));
-      gpr_free(pp);
    } else {
      pp->next = p->pending_picks;
      p->pending_picks = pp;
@ -226,22 +211,21 @@ static void rr_cancel_picks_locked(grpc_lb_policy* pol,
                                   uint32_t initial_metadata_flags_eq,
                                   grpc_error* error) {
  round_robin_lb_policy* p = (round_robin_lb_policy*)pol;
-  pending_pick* pp = p->pending_picks;
+  grpc_lb_policy_pick_state* pick = p->pending_picks;
  p->pending_picks = nullptr;
-  while (pp != nullptr) {
-    pending_pick* next = pp->next;
-    if ((pp->initial_metadata_flags & initial_metadata_flags_mask) ==
+  while (pick != nullptr) {
+    grpc_lb_policy_pick_state* next = pick->next;
+    if ((pick->initial_metadata_flags & initial_metadata_flags_mask) ==
        initial_metadata_flags_eq) {
-      *pp->target = nullptr;
-      GRPC_CLOSURE_SCHED(pp->on_complete,
+      pick->connected_subchannel.reset();
+      GRPC_CLOSURE_SCHED(pick->on_complete,
                         GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
                             "Pick cancelled", &error, 1));
-      gpr_free(pp);
    } else {
-      pp->next = p->pending_picks;
-      p->pending_picks = pp;
+      pick->next = p->pending_picks;
+      p->pending_picks = pick;
    }
-    pp = next;
+    pick = next;
  }
  GRPC_ERROR_UNREF(error);
 }
@ -266,13 +250,10 @@ static void rr_exit_idle_locked(grpc_lb_policy* pol) {
 }

 static int rr_pick_locked(grpc_lb_policy* pol,
-                          const grpc_lb_policy_pick_args* pick_args,
-                          grpc_connected_subchannel** target,
-                          grpc_call_context_element* context, void** user_data,
-                          grpc_closure* on_complete) {
+                          grpc_lb_policy_pick_state* pick) {
  round_robin_lb_policy* p = (round_robin_lb_policy*)pol;
  if (grpc_lb_round_robin_trace.enabled()) {
-    gpr_log(GPR_INFO, "[RR %p] Trying to pick (shutdown: %d)", (void*)pol,
+    gpr_log(GPR_INFO, "[RR %p] Trying to pick (shutdown: %d)", pol,
            p->shutdown);
  }
  GPR_ASSERT(!p->shutdown);
@ -282,18 +263,17 @@ static int rr_pick_locked(grpc_lb_policy* pol,
      /* readily available, report right away */
      grpc_lb_subchannel_data* sd =
          &p->subchannel_list->subchannels[next_ready_index];
-      *target =
-          GRPC_CONNECTED_SUBCHANNEL_REF(sd->connected_subchannel, "rr_picked");
-      if (user_data != nullptr) {
-        *user_data = sd->user_data;
+      pick->connected_subchannel = sd->connected_subchannel;
+      if (pick->user_data != nullptr) {
+        *pick->user_data = sd->user_data;
      }
      if (grpc_lb_round_robin_trace.enabled()) {
        gpr_log(
            GPR_DEBUG,
            "[RR %p] Picked target <-- Subchannel %p (connected %p) (sl %p, "
-            "index %lu)",
-            (void*)p, (void*)sd->subchannel, (void*)*target,
-            (void*)sd->subchannel_list, (unsigned long)next_ready_index);
+            "index %" PRIuPTR ")",
+            p, sd->subchannel, pick->connected_subchannel.get(),
+            sd->subchannel_list, next_ready_index);
      }
      /* only advance the last picked pointer if the selection was used */
      update_last_ready_subchannel_index_locked(p, next_ready_index);
@ -304,27 +284,21 @@ static int rr_pick_locked(grpc_lb_policy* pol,
  if (!p->started_picking) {
    start_picking_locked(p);
  }
-  pending_pick* pp = (pending_pick*)gpr_malloc(sizeof(*pp));
-  pp->next = p->pending_picks;
-  pp->target = target;
-  pp->on_complete = on_complete;
-  pp->initial_metadata_flags = pick_args->initial_metadata_flags;
-  pp->user_data = user_data;
-  p->pending_picks = pp;
+  pick->next = p->pending_picks;
+  p->pending_picks = pick;
  return 0;
 }

 static void update_state_counters_locked(grpc_lb_subchannel_data* sd) {
  grpc_lb_subchannel_list* subchannel_list = sd->subchannel_list;
+  GPR_ASSERT(sd->prev_connectivity_state != GRPC_CHANNEL_SHUTDOWN);
+  GPR_ASSERT(sd->curr_connectivity_state != GRPC_CHANNEL_SHUTDOWN);
  if (sd->prev_connectivity_state == GRPC_CHANNEL_READY) {
    GPR_ASSERT(subchannel_list->num_ready > 0);
    --subchannel_list->num_ready;
  } else if (sd->prev_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
    GPR_ASSERT(subchannel_list->num_transient_failures > 0);
    --subchannel_list->num_transient_failures;
-  } else if (sd->prev_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
-    GPR_ASSERT(subchannel_list->num_shutdown > 0);
-    --subchannel_list->num_shutdown;
  } else if (sd->prev_connectivity_state == GRPC_CHANNEL_IDLE) {
    GPR_ASSERT(subchannel_list->num_idle > 0);
    --subchannel_list->num_idle;
@ -334,8 +308,6 @@ static void update_state_counters_locked(grpc_lb_subchannel_data* sd) {
    ++subchannel_list->num_ready;
  } else if (sd->curr_connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
    ++subchannel_list->num_transient_failures;
-  } else if (sd->curr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
-    ++subchannel_list->num_shutdown;
  } else if (sd->curr_connectivity_state == GRPC_CHANNEL_IDLE) {
    ++subchannel_list->num_idle;
  }
@ -435,6 +407,7 @@ static void rr_connectivity_changed_locked(void* arg, grpc_error* error) {
  // either the current or latest pending subchannel lists.
  GPR_ASSERT(sd->subchannel_list == p->subchannel_list ||
             sd->subchannel_list == p->latest_pending_subchannel_list);
+  GPR_ASSERT(sd->pending_connectivity_state_unsafe != GRPC_CHANNEL_SHUTDOWN);
  // Now that we're inside the combiner, copy the pending connectivity
  // state (which was set by the connectivity state watcher) to
  // curr_connectivity_state, which is what we use inside of the combiner.
@ -442,18 +415,17 @@ static void rr_connectivity_changed_locked(void* arg, grpc_error* error) {
  // Update state counters and new overall state.
  update_state_counters_locked(sd);
  update_lb_connectivity_status_locked(sd, GRPC_ERROR_REF(error));
-  // If the sd's new state is SHUTDOWN, unref the subchannel.
-  if (sd->curr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
-    grpc_lb_subchannel_data_stop_connectivity_watch(sd);
-    grpc_lb_subchannel_data_unref_subchannel(sd, "rr_connectivity_shutdown");
-    grpc_lb_subchannel_list_unref_for_connectivity_watch(
-        sd->subchannel_list, "rr_connectivity_shutdown");
-  } else {  // sd not in SHUTDOWN
-    if (sd->curr_connectivity_state == GRPC_CHANNEL_READY) {
+  // If the sd's new state is TRANSIENT_FAILURE, unref the *connected*
+  // subchannel, if any.
+  switch (sd->curr_connectivity_state) {
+    case GRPC_CHANNEL_TRANSIENT_FAILURE: {
+      sd->connected_subchannel.reset();
+      break;
+    }
+    case GRPC_CHANNEL_READY: {
      if (sd->connected_subchannel == nullptr) {
-        sd->connected_subchannel = GRPC_CONNECTED_SUBCHANNEL_REF(
-            grpc_subchannel_get_connected_subchannel(sd->subchannel),
-            "connected");
+        sd->connected_subchannel =
+            grpc_subchannel_get_connected_subchannel(sd->subchannel);
      }
      if (sd->subchannel_list != p->subchannel_list) {
        // promote sd->subchannel_list to p->subchannel_list.
@ -493,13 +465,12 @@ static void rr_connectivity_changed_locked(void* arg, grpc_error* error) {
        // picks, update the last picked pointer
        update_last_ready_subchannel_index_locked(p, next_ready_index);
      }
-      pending_pick* pp;
-      while ((pp = p->pending_picks)) {
-        p->pending_picks = pp->next;
-        *pp->target = GRPC_CONNECTED_SUBCHANNEL_REF(
-            selected->connected_subchannel, "rr_picked");
-        if (pp->user_data != nullptr) {
-          *pp->user_data = selected->user_data;
+      grpc_lb_policy_pick_state* pick;
+      while ((pick = p->pending_picks)) {
+        p->pending_picks = pick->next;
+        pick->connected_subchannel = selected->connected_subchannel;
+        if (pick->user_data != nullptr) {
+          *pick->user_data = selected->user_data;
        }
        if (grpc_lb_round_robin_trace.enabled()) {
          gpr_log(GPR_DEBUG,
@ -508,13 +479,17 @@ static void rr_connectivity_changed_locked(void* arg, grpc_error* error) {
                  (void*)p, (void*)selected->subchannel,
                  (void*)p->subchannel_list, (unsigned long)next_ready_index);
        }
-        GRPC_CLOSURE_SCHED(pp->on_complete, GRPC_ERROR_NONE);
-        gpr_free(pp);
+        GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_NONE);
      }
+      break;
    }
-    // Renew notification.
-    grpc_lb_subchannel_data_start_connectivity_watch(sd);
+    case GRPC_CHANNEL_SHUTDOWN:
+      GPR_UNREACHABLE_CODE(return );
+    case GRPC_CHANNEL_CONNECTING:
+    case GRPC_CHANNEL_IDLE:;  // fallthrough
  }
+  // Renew notification.
+  grpc_lb_subchannel_data_start_connectivity_watch(sd);
 }

 static grpc_connectivity_state rr_check_connectivity_locked(
@ -538,10 +513,9 @@ static void rr_ping_one_locked(grpc_lb_policy* pol, grpc_closure* on_initiate,
  if (next_ready_index < p->subchannel_list->num_subchannels) {
    grpc_lb_subchannel_data* selected =
        &p->subchannel_list->subchannels[next_ready_index];
-    grpc_connected_subchannel* target = GRPC_CONNECTED_SUBCHANNEL_REF(
-        selected->connected_subchannel, "rr_ping");
-    grpc_connected_subchannel_ping(target, on_initiate, on_ack);
-    GRPC_CONNECTED_SUBCHANNEL_UNREF(target, "rr_ping");
+    grpc_core::RefCountedPtr<grpc_core::ConnectedSubchannel> target =
+        selected->connected_subchannel;
+    target->Ping(on_initiate, on_ack);
  } else {
    GRPC_CLOSURE_SCHED(on_initiate, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                                        "Round Robin not connected"));
--- a/src/core/ext/filters/client_channel/lb_policy/subchannel_list.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/subchannel_list.cc
@ -42,10 +42,7 @@ void grpc_lb_subchannel_data_unref_subchannel(grpc_lb_subchannel_data* sd,
    }
    GRPC_SUBCHANNEL_UNREF(sd->subchannel, reason);
    sd->subchannel = nullptr;
-    if (sd->connected_subchannel != nullptr) {
-      GRPC_CONNECTED_SUBCHANNEL_UNREF(sd->connected_subchannel, reason);
-      sd->connected_subchannel = nullptr;
-    }
+    sd->connected_subchannel.reset();
    if (sd->user_data != nullptr) {
      GPR_ASSERT(sd->user_data_vtable != nullptr);
      sd->user_data_vtable->destroy(sd->user_data);
@ -213,13 +210,13 @@ void grpc_lb_subchannel_list_unref(grpc_lb_subchannel_list* subchannel_list,

 void grpc_lb_subchannel_list_ref_for_connectivity_watch(
    grpc_lb_subchannel_list* subchannel_list, const char* reason) {
-  GRPC_LB_POLICY_WEAK_REF(subchannel_list->policy, reason);
+  GRPC_LB_POLICY_REF(subchannel_list->policy, reason);
  grpc_lb_subchannel_list_ref(subchannel_list, reason);
 }

 void grpc_lb_subchannel_list_unref_for_connectivity_watch(
    grpc_lb_subchannel_list* subchannel_list, const char* reason) {
-  GRPC_LB_POLICY_WEAK_UNREF(subchannel_list->policy, reason);
+  GRPC_LB_POLICY_UNREF(subchannel_list->policy, reason);
  grpc_lb_subchannel_list_unref(subchannel_list, reason);
 }

--- a/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
+++ b/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
@ -22,6 +22,7 @@
 #include "src/core/ext/filters/client_channel/lb_policy_registry.h"
 #include "src/core/ext/filters/client_channel/subchannel.h"
 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/transport/connectivity_state.h"

 // TODO(roth): This code is intended to be shared between pick_first and
@ -43,7 +44,7 @@ typedef struct {
  grpc_lb_subchannel_list* subchannel_list;
  /** subchannel itself */
  grpc_subchannel* subchannel;
-  grpc_connected_subchannel* connected_subchannel;
+  grpc_core::RefCountedPtr<grpc_core::ConnectedSubchannel> connected_subchannel;
  /** Is a connectivity notification pending? */
  bool connectivity_notification_pending;
  /** notification that connectivity has changed on subchannel */
--- a/src/core/ext/filters/client_channel/lb_policy_registry.cc
+++ b/src/core/ext/filters/client_channel/lb_policy_registry.cc
@ -20,7 +20,7 @@

 #include <string.h>

-#include "src/core/lib/support/string.h"
+#include "src/core/lib/gpr/string.h"

 #define MAX_POLICIES 10

--- a/src/core/ext/filters/client_channel/parse_address.cc
+++ b/src/core/ext/filters/client_channel/parse_address.cc
@ -29,7 +29,7 @@
 #include <grpc/support/host_port.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
-#include "src/core/lib/support/string.h"
+#include "src/core/lib/gpr/string.h"

 #ifdef GRPC_HAVE_UNIX_SOCKET

--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
@ -34,14 +34,14 @@
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gprpp/manual_constructor.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/gethostname.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/json/json.h"
-#include "src/core/lib/support/env.h"
-#include "src/core/lib/support/manual_constructor.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/service_config.h"

 #define GRPC_DNS_INITIAL_CONNECT_BACKOFF_SECONDS 1
@ -264,7 +264,7 @@ static void dns_ares_on_resolved_locked(void* arg, grpc_error* error) {
  } else {
    const char* msg = grpc_error_string(error);
    gpr_log(GPR_DEBUG, "dns resolution failed: %s", msg);
-    grpc_millis next_try = r->backoff->Step();
+    grpc_millis next_try = r->backoff->NextAttemptTime();
    grpc_millis timeout = next_try - grpc_core::ExecCtx::Get()->Now();
    gpr_log(GPR_INFO, "dns resolution failed (will retry): %s",
            grpc_error_string(error));
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
@ -30,10 +30,10 @@
 #include <grpc/support/time.h>
 #include <grpc/support/useful.h>
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
-#include "src/core/lib/support/string.h"

 typedef struct fd_node {
  /** the owner of this fd node */
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
@ -36,12 +36,12 @@

 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/nameser.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
-#include "src/core/lib/support/string.h"

 static gpr_once g_basic_init = GPR_ONCE_INIT;
 static gpr_mu g_init_mu;
--- a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
@ -29,12 +29,12 @@
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/lib/backoff/backoff.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gprpp/manual_constructor.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/timer.h"
-#include "src/core/lib/support/env.h"
-#include "src/core/lib/support/manual_constructor.h"
-#include "src/core/lib/support/string.h"

 #define GRPC_DNS_INITIAL_CONNECT_BACKOFF_SECONDS 1
 #define GRPC_DNS_RECONNECT_BACKOFF_MULTIPLIER 1.6
@ -161,7 +161,7 @@ static void dns_on_resolved_locked(void* arg, grpc_error* error) {
    grpc_resolved_addresses_destroy(r->addresses);
    grpc_lb_addresses_destroy(addresses);
  } else {
-    grpc_millis next_try = r->backoff->Step();
+    grpc_millis next_try = r->backoff->NextAttemptTime();
    grpc_millis timeout = next_try - grpc_core::ExecCtx::Get()->Now();
    gpr_log(GPR_INFO, "dns resolution failed (will retry): %s",
            grpc_error_string(error));
--- a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
@ -32,13 +32,13 @@
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/closure.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"

 #include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"

--- a/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
+++ b/src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
@ -30,12 +30,12 @@
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/resolver_registry.h"
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"

 typedef struct {
  /** base class: must be first */
--- a/src/core/ext/filters/client_channel/subchannel.cc
+++ b/src/core/ext/filters/client_channel/subchannel.cc
@ -37,11 +37,12 @@
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/connected_channel.h"
 #include "src/core/lib/debug/stats.h"
+#include "src/core/lib/gprpp/debug_location.h"
+#include "src/core/lib/gprpp/manual_constructor.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
-#include "src/core/lib/support/manual_constructor.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/surface/channel_init.h"
 #include "src/core/lib/transport/connectivity_state.h"
@ -55,15 +56,13 @@
 #define GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS 120
 #define GRPC_SUBCHANNEL_RECONNECT_JITTER 0.2

-#define GET_CONNECTED_SUBCHANNEL(subchannel, barrier)     \
-  ((grpc_connected_subchannel*)(gpr_atm_##barrier##_load( \
-      &(subchannel)->connected_subchannel)))
-
-typedef struct {
+namespace {
+struct state_watcher {
  grpc_closure closure;
  grpc_subchannel* subchannel;
  grpc_connectivity_state connectivity_state;
-} state_watcher;
+};
+}  // namespace

 typedef struct external_state_watcher {
  grpc_subchannel* subchannel;
@ -96,7 +95,7 @@ struct grpc_subchannel {
  grpc_connect_out_args connecting_result;

  /** callback for connection finishing */
-  grpc_closure connected;
+  grpc_closure on_connected;

  /** callback for our alarm */
  grpc_closure on_alarm;
@ -105,12 +104,13 @@ struct grpc_subchannel {
      being setup */
  grpc_pollset_set* pollset_set;

-  /** active connection, or null; of type grpc_connected_subchannel */
-  gpr_atm connected_subchannel;
-
  /** mutex protecting remaining elements */
  gpr_mu mu;

+  /** active connection, or null; of type grpc_core::ConnectedSubchannel
+   */
+  grpc_core::RefCountedPtr<grpc_core::ConnectedSubchannel> connected_subchannel;
+
  /** have we seen a disconnection? */
  bool disconnected;
  /** are we connecting */
@ -134,16 +134,15 @@ struct grpc_subchannel {
 };

 struct grpc_subchannel_call {
-  grpc_connected_subchannel* connection;
+  grpc_core::ConnectedSubchannel* connection;
  grpc_closure* schedule_closure_after_destroy;
 };

 #define SUBCHANNEL_CALL_TO_CALL_STACK(call) ((grpc_call_stack*)((call) + 1))
-#define CHANNEL_STACK_FROM_CONNECTION(con) ((grpc_channel_stack*)(con))
 #define CALLSTACK_TO_SUBCHANNEL_CALL(callstack) \
  (((grpc_subchannel_call*)(callstack)) - 1)

-static void subchannel_connected(void* subchannel, grpc_error* error);
+static void on_subchannel_connected(void* subchannel, grpc_error* error);

 #ifndef NDEBUG
 #define REF_REASON reason
@ -161,20 +160,9 @@ static void subchannel_connected(void* subchannel, grpc_error* error);
 */

 static void connection_destroy(void* arg, grpc_error* error) {
-  grpc_connected_subchannel* c = (grpc_connected_subchannel*)arg;
-  grpc_channel_stack_destroy(CHANNEL_STACK_FROM_CONNECTION(c));
-  gpr_free(c);
-}
-
-grpc_connected_subchannel* grpc_connected_subchannel_ref(
-    grpc_connected_subchannel* c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  GRPC_CHANNEL_STACK_REF(CHANNEL_STACK_FROM_CONNECTION(c), REF_REASON);
-  return c;
-}
-
-void grpc_connected_subchannel_unref(
-    grpc_connected_subchannel* c GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
-  GRPC_CHANNEL_STACK_UNREF(CHANNEL_STACK_FROM_CONNECTION(c), REF_REASON);
+  grpc_channel_stack* stk = (grpc_channel_stack*)arg;
+  grpc_channel_stack_destroy(stk);
+  gpr_free(stk);
 }

 /*
@ -241,18 +229,13 @@ grpc_subchannel* grpc_subchannel_ref_from_weak_ref(
 }

 static void disconnect(grpc_subchannel* c) {
-  grpc_connected_subchannel* con;
  grpc_subchannel_index_unregister(c->key, c);
  gpr_mu_lock(&c->mu);
  GPR_ASSERT(!c->disconnected);
  c->disconnected = true;
  grpc_connector_shutdown(c->connector, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                                            "Subchannel disconnected"));
-  con = GET_CONNECTED_SUBCHANNEL(c, no_barrier);
-  if (con != nullptr) {
-    GRPC_CONNECTED_SUBCHANNEL_UNREF(con, "connection");
-    gpr_atm_no_barrier_store(&c->connected_subchannel, (gpr_atm)0xdeadbeef);
-  }
+  c->connected_subchannel.reset();
  gpr_mu_unlock(&c->mu);
 }

@ -372,7 +355,7 @@ grpc_subchannel* grpc_subchannel_create(grpc_connector* connector,
  if (new_args != nullptr) grpc_channel_args_destroy(new_args);
  c->root_external_state_watcher.next = c->root_external_state_watcher.prev =
      &c->root_external_state_watcher;
-  GRPC_CLOSURE_INIT(&c->connected, subchannel_connected, c,
+  GRPC_CLOSURE_INIT(&c->on_connected, on_subchannel_connected, c,
                    grpc_schedule_on_exec_ctx);
  grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE,
                               "subchannel");
@ -390,12 +373,13 @@ static void continue_connect_locked(grpc_subchannel* c) {
  args.interested_parties = c->pollset_set;
  const grpc_millis min_deadline =
      c->min_connect_timeout_ms + grpc_core::ExecCtx::Get()->Now();
+  c->next_attempt_deadline = c->backoff->NextAttemptTime();
  args.deadline = std::max(c->next_attempt_deadline, min_deadline);
  args.channel_args = c->args;
  grpc_connectivity_state_set(&c->state_tracker, GRPC_CHANNEL_CONNECTING,
                              GRPC_ERROR_NONE, "state_change");
  grpc_connector_connect(c->connector, &args, &c->connecting_result,
-                         &c->connected);
+                         &c->on_connected);
 }

 grpc_connectivity_state grpc_subchannel_check_connectivity(grpc_subchannel* c,
@ -435,7 +419,6 @@ static void on_alarm(void* arg, grpc_error* error) {
  }
  if (error == GRPC_ERROR_NONE) {
    gpr_log(GPR_INFO, "Failed to connect to channel, retrying");
-    c->next_attempt_deadline = c->backoff->Step();
    continue_connect_locked(c);
    gpr_mu_unlock(&c->mu);
  } else {
@ -456,7 +439,7 @@ static void maybe_start_connecting_locked(grpc_subchannel* c) {
    return;
  }

-  if (GET_CONNECTED_SUBCHANNEL(c, no_barrier) != nullptr) {
+  if (c->connected_subchannel != nullptr) {
    /* Already connected: don't restart */
    return;
  }
@ -471,7 +454,6 @@ static void maybe_start_connecting_locked(grpc_subchannel* c) {

  if (!c->backoff_begun) {
    c->backoff_begun = true;
-    c->next_attempt_deadline = c->backoff->Begin();
    continue_connect_locked(c);
  } else {
    GPR_ASSERT(!c->have_alarm);
@ -479,9 +461,10 @@ static void maybe_start_connecting_locked(grpc_subchannel* c) {
    const grpc_millis time_til_next =
        c->next_attempt_deadline - grpc_core::ExecCtx::Get()->Now();
    if (time_til_next <= 0) {
-      gpr_log(GPR_INFO, "Retry immediately");
+      gpr_log(GPR_INFO, "Subchannel %p: Retry immediately", c);
    } else {
-      gpr_log(GPR_INFO, "Retry in %" PRIdPTR " milliseconds", time_til_next);
+      gpr_log(GPR_INFO, "Subchannel %p: Retry in %" PRIdPTR " milliseconds", c,
+              time_til_next);
    }
    GRPC_CLOSURE_INIT(&c->on_alarm, on_alarm, c, grpc_schedule_on_exec_ctx);
    grpc_timer_init(&c->alarm, c->next_attempt_deadline, &c->on_alarm);
@ -525,75 +508,56 @@ void grpc_subchannel_notify_on_state_change(
  }
 }

-void grpc_connected_subchannel_process_transport_op(
-    grpc_connected_subchannel* con, grpc_transport_op* op) {
-  grpc_channel_stack* channel_stack = CHANNEL_STACK_FROM_CONNECTION(con);
-  grpc_channel_element* top_elem = grpc_channel_stack_element(channel_stack, 0);
-  top_elem->filter->start_transport_op(top_elem, op);
-}
-
-static void subchannel_on_child_state_changed(void* p, grpc_error* error) {
-  state_watcher* sw = (state_watcher*)p;
-  grpc_subchannel* c = sw->subchannel;
+static void on_connected_subchannel_connectivity_changed(void* p,
+                                                         grpc_error* error) {
+  state_watcher* connected_subchannel_watcher = (state_watcher*)p;
+  grpc_subchannel* c = connected_subchannel_watcher->subchannel;
  gpr_mu* mu = &c->mu;

  gpr_mu_lock(mu);

-  /* if we failed just leave this closure */
-  if (sw->connectivity_state == GRPC_CHANNEL_TRANSIENT_FAILURE) {
-    /* any errors on a subchannel ==> we're done, create a new one */
-    sw->connectivity_state = GRPC_CHANNEL_SHUTDOWN;
-  }
-  grpc_connectivity_state_set(&c->state_tracker, sw->connectivity_state,
-                              GRPC_ERROR_REF(error), "reflect_child");
-  if (sw->connectivity_state != GRPC_CHANNEL_SHUTDOWN) {
-    grpc_connected_subchannel_notify_on_state_change(
-        GET_CONNECTED_SUBCHANNEL(c, no_barrier), nullptr,
-        &sw->connectivity_state, &sw->closure);
-    GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
-    sw = nullptr;
+  switch (connected_subchannel_watcher->connectivity_state) {
+    case GRPC_CHANNEL_TRANSIENT_FAILURE:
+    case GRPC_CHANNEL_SHUTDOWN: {
+      if (!c->disconnected && c->connected_subchannel != nullptr) {
+        if (grpc_trace_stream_refcount.enabled()) {
+          gpr_log(GPR_INFO,
+                  "Connected subchannel %p of subchannel %p has gone into %s. "
+                  "Attempting to reconnect.",
+                  c->connected_subchannel.get(), c,
+                  grpc_connectivity_state_name(
+                      connected_subchannel_watcher->connectivity_state));
+        }
+        c->connected_subchannel.reset();
+        grpc_connectivity_state_set(&c->state_tracker,
+                                    GRPC_CHANNEL_TRANSIENT_FAILURE,
+                                    GRPC_ERROR_REF(error), "reflect_child");
+        c->backoff_begun = false;
+        c->backoff->Reset();
+        maybe_start_connecting_locked(c);
+      } else {
+        connected_subchannel_watcher->connectivity_state =
+            GRPC_CHANNEL_SHUTDOWN;
+      }
+      break;
+    }
+    default: {
+      grpc_connectivity_state_set(
+          &c->state_tracker, connected_subchannel_watcher->connectivity_state,
+          GRPC_ERROR_REF(error), "reflect_child");
+      GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
+      c->connected_subchannel->NotifyOnStateChange(
+          nullptr, &connected_subchannel_watcher->connectivity_state,
+          &connected_subchannel_watcher->closure);
+      connected_subchannel_watcher = nullptr;
+    }
  }
-
  gpr_mu_unlock(mu);
  GRPC_SUBCHANNEL_WEAK_UNREF(c, "state_watcher");
-  gpr_free(sw);
-}
-
-static void connected_subchannel_state_op(grpc_connected_subchannel* con,
-                                          grpc_pollset_set* interested_parties,
-                                          grpc_connectivity_state* state,
-                                          grpc_closure* closure) {
-  grpc_transport_op* op = grpc_make_transport_op(nullptr);
-  grpc_channel_element* elem;
-  op->connectivity_state = state;
-  op->on_connectivity_state_change = closure;
-  op->bind_pollset_set = interested_parties;
-  elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CONNECTION(con), 0);
-  elem->filter->start_transport_op(elem, op);
-}
-
-void grpc_connected_subchannel_notify_on_state_change(
-    grpc_connected_subchannel* con, grpc_pollset_set* interested_parties,
-    grpc_connectivity_state* state, grpc_closure* closure) {
-  connected_subchannel_state_op(con, interested_parties, state, closure);
-}
-
-void grpc_connected_subchannel_ping(grpc_connected_subchannel* con,
-                                    grpc_closure* on_initiate,
-                                    grpc_closure* on_ack) {
-  grpc_transport_op* op = grpc_make_transport_op(nullptr);
-  grpc_channel_element* elem;
-  op->send_ping.on_initiate = on_initiate;
-  op->send_ping.on_ack = on_ack;
-  elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CONNECTION(con), 0);
-  elem->filter->start_transport_op(elem, op);
+  gpr_free(connected_subchannel_watcher);
 }

 static bool publish_transport_locked(grpc_subchannel* c) {
-  grpc_connected_subchannel* con;
-  grpc_channel_stack* stk;
-  state_watcher* sw_subchannel;
-
  /* construct channel stack */
  grpc_channel_stack_builder* builder = grpc_channel_stack_builder_create();
  grpc_channel_stack_builder_set_channel_arguments(
@ -605,8 +569,9 @@ static bool publish_transport_locked(grpc_subchannel* c) {
    grpc_channel_stack_builder_destroy(builder);
    return false;
  }
+  grpc_channel_stack* stk;
  grpc_error* error = grpc_channel_stack_builder_finish(
-      builder, 0, 1, connection_destroy, nullptr, (void**)&con);
+      builder, 0, 1, connection_destroy, nullptr, (void**)&stk);
  if (error != GRPC_ERROR_NONE) {
    grpc_transport_destroy(c->connecting_result.transport);
    gpr_log(GPR_ERROR, "error initializing subchannel stack: %s",
@ -614,38 +579,37 @@ static bool publish_transport_locked(grpc_subchannel* c) {
    GRPC_ERROR_UNREF(error);
    return false;
  }
-  stk = CHANNEL_STACK_FROM_CONNECTION(con);
  memset(&c->connecting_result, 0, sizeof(c->connecting_result));

  /* initialize state watcher */
-  sw_subchannel = (state_watcher*)gpr_malloc(sizeof(*sw_subchannel));
-  sw_subchannel->subchannel = c;
-  sw_subchannel->connectivity_state = GRPC_CHANNEL_READY;
-  GRPC_CLOSURE_INIT(&sw_subchannel->closure, subchannel_on_child_state_changed,
-                    sw_subchannel, grpc_schedule_on_exec_ctx);
+  state_watcher* connected_subchannel_watcher =
+      (state_watcher*)gpr_zalloc(sizeof(*connected_subchannel_watcher));
+  connected_subchannel_watcher->subchannel = c;
+  connected_subchannel_watcher->connectivity_state = GRPC_CHANNEL_READY;
+  GRPC_CLOSURE_INIT(&connected_subchannel_watcher->closure,
+                    on_connected_subchannel_connectivity_changed,
+                    connected_subchannel_watcher, grpc_schedule_on_exec_ctx);

  if (c->disconnected) {
-    gpr_free(sw_subchannel);
+    gpr_free(connected_subchannel_watcher);
    grpc_channel_stack_destroy(stk);
-    gpr_free(con);
+    gpr_free(stk);
    return false;
  }

  /* publish */
-  /* TODO(ctiller): this full barrier seems to clear up a TSAN failure.
-                    I'd have expected the rel_cas below to be enough, but
-                    seemingly it's not.
-                    Re-evaluate if we really need this. */
-  gpr_atm_full_barrier();
-  GPR_ASSERT(gpr_atm_rel_cas(&c->connected_subchannel, 0, (gpr_atm)con));
+  c->connected_subchannel.reset(
+      grpc_core::New<grpc_core::ConnectedSubchannel>(stk));
+  gpr_log(GPR_INFO, "New connected subchannel at %p for subchannel %p",
+          c->connected_subchannel.get(), c);

  /* setup subchannel watching connected subchannel for changes; subchannel
     ref for connecting is donated to the state watcher */
  GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
  GRPC_SUBCHANNEL_WEAK_UNREF(c, "connecting");
-  grpc_connected_subchannel_notify_on_state_change(
-      con, c->pollset_set, &sw_subchannel->connectivity_state,
-      &sw_subchannel->closure);
+  c->connected_subchannel->NotifyOnStateChange(
+      c->pollset_set, &connected_subchannel_watcher->connectivity_state,
+      &connected_subchannel_watcher->closure);

  /* signal completion */
  grpc_connectivity_state_set(&c->state_tracker, GRPC_CHANNEL_READY,
@ -653,11 +617,11 @@ static bool publish_transport_locked(grpc_subchannel* c) {
  return true;
 }

-static void subchannel_connected(void* arg, grpc_error* error) {
+static void on_subchannel_connected(void* arg, grpc_error* error) {
  grpc_subchannel* c = (grpc_subchannel*)arg;
  grpc_channel_args* delete_channel_args = c->connecting_result.channel_args;

-  GRPC_SUBCHANNEL_WEAK_REF(c, "connected");
+  GRPC_SUBCHANNEL_WEAK_REF(c, "on_subchannel_connected");
  gpr_mu_lock(&c->mu);
  c->connecting = false;
  if (c->connecting_result.transport != nullptr &&
@ -692,10 +656,10 @@ static void subchannel_call_destroy(void* call, grpc_error* error) {
  grpc_subchannel_call* c = (grpc_subchannel_call*)call;
  GPR_ASSERT(c->schedule_closure_after_destroy != nullptr);
  GPR_TIMER_BEGIN("grpc_subchannel_call_unref.destroy", 0);
-  grpc_connected_subchannel* connection = c->connection;
+  grpc_core::ConnectedSubchannel* connection = c->connection;
  grpc_call_stack_destroy(SUBCHANNEL_CALL_TO_CALL_STACK(c), nullptr,
                          c->schedule_closure_after_destroy);
-  GRPC_CONNECTED_SUBCHANNEL_UNREF(connection, "subchannel_call");
+  connection->Unref(DEBUG_LOCATION, "subchannel_call");
  GPR_TIMER_END("grpc_subchannel_call_unref.destroy", 0);
 }

@ -726,9 +690,12 @@ void grpc_subchannel_call_process_op(grpc_subchannel_call* call,
  GPR_TIMER_END("grpc_subchannel_call_process_op", 0);
 }

-grpc_connected_subchannel* grpc_subchannel_get_connected_subchannel(
-    grpc_subchannel* c) {
-  return GET_CONNECTED_SUBCHANNEL(c, acq);
+grpc_core::RefCountedPtr<grpc_core::ConnectedSubchannel>
+grpc_subchannel_get_connected_subchannel(grpc_subchannel* c) {
+  gpr_mu_lock(&c->mu);
+  auto copy = c->connected_subchannel;
+  gpr_mu_unlock(&c->mu);
+  return copy;
 }

 const grpc_subchannel_key* grpc_subchannel_get_key(
@ -736,36 +703,6 @@ const grpc_subchannel_key* grpc_subchannel_get_key(
  return subchannel->key;
 }

-grpc_error* grpc_connected_subchannel_create_call(
-    grpc_connected_subchannel* con,
-    const grpc_connected_subchannel_call_args* args,
-    grpc_subchannel_call** call) {
-  grpc_channel_stack* chanstk = CHANNEL_STACK_FROM_CONNECTION(con);
-  *call = (grpc_subchannel_call*)gpr_arena_alloc(
-      args->arena, sizeof(grpc_subchannel_call) + chanstk->call_stack_size);
-  grpc_call_stack* callstk = SUBCHANNEL_CALL_TO_CALL_STACK(*call);
-  (*call)->connection = GRPC_CONNECTED_SUBCHANNEL_REF(con, "subchannel_call");
-  const grpc_call_element_args call_args = {
-      callstk,            /* call_stack */
-      nullptr,            /* server_transport_data */
-      args->context,      /* context */
-      args->path,         /* path */
-      args->start_time,   /* start_time */
-      args->deadline,     /* deadline */
-      args->arena,        /* arena */
-      args->call_combiner /* call_combiner */
-  };
-  grpc_error* error = grpc_call_stack_init(chanstk, 1, subchannel_call_destroy,
-                                           *call, &call_args);
-  if (error != GRPC_ERROR_NONE) {
-    const char* error_string = grpc_error_string(error);
-    gpr_log(GPR_ERROR, "error: %s", error_string);
-    return error;
-  }
-  grpc_call_stack_set_pollset_or_pollset_set(callstk, args->pollent);
-  return GRPC_ERROR_NONE;
-}
-
 grpc_call_stack* grpc_subchannel_call_get_call_stack(
    grpc_subchannel_call* subchannel_call) {
  return SUBCHANNEL_CALL_TO_CALL_STACK(subchannel_call);
@ -801,3 +738,64 @@ grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address* addr) {
      (char*)GRPC_ARG_SUBCHANNEL_ADDRESS,
      addr->len > 0 ? grpc_sockaddr_to_uri(addr) : gpr_strdup(""));
 }
+
+namespace grpc_core {
+ConnectedSubchannel::ConnectedSubchannel(grpc_channel_stack* channel_stack)
+    : grpc_core::RefCountedWithTracing(&grpc_trace_stream_refcount),
+      channel_stack_(channel_stack) {}
+
+ConnectedSubchannel::~ConnectedSubchannel() {
+  GRPC_CHANNEL_STACK_UNREF(channel_stack_, "connected_subchannel_dtor");
+}
+
+void ConnectedSubchannel::NotifyOnStateChange(
+    grpc_pollset_set* interested_parties, grpc_connectivity_state* state,
+    grpc_closure* closure) {
+  grpc_transport_op* op = grpc_make_transport_op(nullptr);
+  grpc_channel_element* elem;
+  op->connectivity_state = state;
+  op->on_connectivity_state_change = closure;
+  op->bind_pollset_set = interested_parties;
+  elem = grpc_channel_stack_element(channel_stack_, 0);
+  elem->filter->start_transport_op(elem, op);
+}
+
+void ConnectedSubchannel::Ping(grpc_closure* on_initiate,
+                               grpc_closure* on_ack) {
+  grpc_transport_op* op = grpc_make_transport_op(nullptr);
+  grpc_channel_element* elem;
+  op->send_ping.on_initiate = on_initiate;
+  op->send_ping.on_ack = on_ack;
+  elem = grpc_channel_stack_element(channel_stack_, 0);
+  elem->filter->start_transport_op(elem, op);
+}
+
+grpc_error* ConnectedSubchannel::CreateCall(const CallArgs& args,
+                                            grpc_subchannel_call** call) {
+  *call = (grpc_subchannel_call*)gpr_arena_alloc(
+      args.arena,
+      sizeof(grpc_subchannel_call) + channel_stack_->call_stack_size);
+  grpc_call_stack* callstk = SUBCHANNEL_CALL_TO_CALL_STACK(*call);
+  Ref(DEBUG_LOCATION, "subchannel_call");
+  (*call)->connection = this;
+  const grpc_call_element_args call_args = {
+      callstk,           /* call_stack */
+      nullptr,           /* server_transport_data */
+      args.context,      /* context */
+      args.path,         /* path */
+      args.start_time,   /* start_time */
+      args.deadline,     /* deadline */
+      args.arena,        /* arena */
+      args.call_combiner /* call_combiner */
+  };
+  grpc_error* error = grpc_call_stack_init(
+      channel_stack_, 1, subchannel_call_destroy, *call, &call_args);
+  if (error != GRPC_ERROR_NONE) {
+    const char* error_string = grpc_error_string(error);
+    gpr_log(GPR_ERROR, "error: %s", error_string);
+    return error;
+  }
+  grpc_call_stack_set_pollset_or_pollset_set(callstk, args.pollent);
+  return GRPC_ERROR_NONE;
+}
+}  // namespace grpc_core
--- a/src/core/ext/filters/client_channel/subchannel.h
+++ b/src/core/ext/filters/client_channel/subchannel.h
@ -21,8 +21,10 @@

 #include "src/core/ext/filters/client_channel/connector.h"
 #include "src/core/lib/channel/channel_stack.h"
+#include "src/core/lib/gpr/arena.h"
+#include "src/core/lib/gprpp/ref_counted.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/iomgr/polling_entity.h"
-#include "src/core/lib/support/arena.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/metadata.h"

@ -32,7 +34,6 @@
 /** A (sub-)channel that knows how to connect to exactly one target
    address. Provides a target for load balancing. */
 typedef struct grpc_subchannel grpc_subchannel;
-typedef struct grpc_connected_subchannel grpc_connected_subchannel;
 typedef struct grpc_subchannel_call grpc_subchannel_call;
 typedef struct grpc_subchannel_args grpc_subchannel_args;
 typedef struct grpc_subchannel_key grpc_subchannel_key;
@ -48,10 +49,6 @@ typedef struct grpc_subchannel_key grpc_subchannel_key;
  grpc_subchannel_weak_ref((p), __FILE__, __LINE__, (r))
 #define GRPC_SUBCHANNEL_WEAK_UNREF(p, r) \
  grpc_subchannel_weak_unref((p), __FILE__, __LINE__, (r))
-#define GRPC_CONNECTED_SUBCHANNEL_REF(p, r) \
-  grpc_connected_subchannel_ref((p), __FILE__, __LINE__, (r))
-#define GRPC_CONNECTED_SUBCHANNEL_UNREF(p, r) \
-  grpc_connected_subchannel_unref((p), __FILE__, __LINE__, (r))
 #define GRPC_SUBCHANNEL_CALL_REF(p, r) \
  grpc_subchannel_call_ref((p), __FILE__, __LINE__, (r))
 #define GRPC_SUBCHANNEL_CALL_UNREF(p, r) \
@ -65,14 +62,39 @@ typedef struct grpc_subchannel_key grpc_subchannel_key;
 #define GRPC_SUBCHANNEL_UNREF(p, r) grpc_subchannel_unref((p))
 #define GRPC_SUBCHANNEL_WEAK_REF(p, r) grpc_subchannel_weak_ref((p))
 #define GRPC_SUBCHANNEL_WEAK_UNREF(p, r) grpc_subchannel_weak_unref((p))
-#define GRPC_CONNECTED_SUBCHANNEL_REF(p, r) grpc_connected_subchannel_ref((p))
-#define GRPC_CONNECTED_SUBCHANNEL_UNREF(p, r) \
-  grpc_connected_subchannel_unref((p))
 #define GRPC_SUBCHANNEL_CALL_REF(p, r) grpc_subchannel_call_ref((p))
 #define GRPC_SUBCHANNEL_CALL_UNREF(p, r) grpc_subchannel_call_unref((p))
 #define GRPC_SUBCHANNEL_REF_EXTRA_ARGS
 #endif

+namespace grpc_core {
+class ConnectedSubchannel : public grpc_core::RefCountedWithTracing {
+ public:
+  struct CallArgs {
+    grpc_polling_entity* pollent;
+    grpc_slice path;
+    gpr_timespec start_time;
+    grpc_millis deadline;
+    gpr_arena* arena;
+    grpc_call_context_element* context;
+    grpc_call_combiner* call_combiner;
+  };
+
+  explicit ConnectedSubchannel(grpc_channel_stack* channel_stack);
+  ~ConnectedSubchannel();
+
+  grpc_channel_stack* channel_stack() { return channel_stack_; }
+  void NotifyOnStateChange(grpc_pollset_set* interested_parties,
+                           grpc_connectivity_state* state,
+                           grpc_closure* closure);
+  void Ping(grpc_closure* on_initiate, grpc_closure* on_ack);
+  grpc_error* CreateCall(const CallArgs& args, grpc_subchannel_call** call);
+
+ private:
+  grpc_channel_stack* channel_stack_;
+};
+}  // namespace grpc_core
+
 grpc_subchannel* grpc_subchannel_ref(
    grpc_subchannel* channel GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
 grpc_subchannel* grpc_subchannel_ref_from_weak_ref(
@ -83,35 +105,11 @@ grpc_subchannel* grpc_subchannel_weak_ref(
    grpc_subchannel* channel GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
 void grpc_subchannel_weak_unref(
    grpc_subchannel* channel GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
-grpc_connected_subchannel* grpc_connected_subchannel_ref(
-    grpc_connected_subchannel* channel GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
-void grpc_connected_subchannel_unref(
-    grpc_connected_subchannel* channel GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
 void grpc_subchannel_call_ref(
    grpc_subchannel_call* call GRPC_SUBCHANNEL_REF_EXTRA_ARGS);
 void grpc_subchannel_call_unref(
    grpc_subchannel_call* call GRPC_SUBCHANNEL_REF_EXTRA_ARGS);

-/** construct a subchannel call */
-typedef struct {
-  grpc_polling_entity* pollent;
-  grpc_slice path;
-  gpr_timespec start_time;
-  grpc_millis deadline;
-  gpr_arena* arena;
-  grpc_call_context_element* context;
-  grpc_call_combiner* call_combiner;
-} grpc_connected_subchannel_call_args;
-
-grpc_error* grpc_connected_subchannel_create_call(
-    grpc_connected_subchannel* connected_subchannel,
-    const grpc_connected_subchannel_call_args* args,
-    grpc_subchannel_call** subchannel_call);
-
-/** process a transport level op */
-void grpc_connected_subchannel_process_transport_op(
-    grpc_connected_subchannel* subchannel, grpc_transport_op* op);
-
 /** poll the current connectivity state of a channel */
 grpc_connectivity_state grpc_subchannel_check_connectivity(
    grpc_subchannel* channel, grpc_error** error);
@ -121,17 +119,12 @@ grpc_connectivity_state grpc_subchannel_check_connectivity(
 void grpc_subchannel_notify_on_state_change(
    grpc_subchannel* channel, grpc_pollset_set* interested_parties,
    grpc_connectivity_state* state, grpc_closure* notify);
-void grpc_connected_subchannel_notify_on_state_change(
-    grpc_connected_subchannel* channel, grpc_pollset_set* interested_parties,
-    grpc_connectivity_state* state, grpc_closure* notify);
-void grpc_connected_subchannel_ping(grpc_connected_subchannel* channel,
-                                    grpc_closure* on_initiate,
-                                    grpc_closure* on_ack);
-
-/** retrieve the grpc_connected_subchannel - or NULL if called before
-    the subchannel becomes connected */
-grpc_connected_subchannel* grpc_subchannel_get_connected_subchannel(
-    grpc_subchannel* subchannel);
+
+/** retrieve the grpc_core::ConnectedSubchannel - or nullptr if not connected
+ * (which may happen before it initially connects or during transient failures)
+ * */
+grpc_core::RefCountedPtr<grpc_core::ConnectedSubchannel>
+grpc_subchannel_get_connected_subchannel(grpc_subchannel* c);

 /** return the subchannel index key for \a subchannel */
 const grpc_subchannel_key* grpc_subchannel_get_key(
--- a/src/core/ext/filters/client_channel/uri_parser.cc
+++ b/src/core/ext/filters/client_channel/uri_parser.cc
@ -26,10 +26,10 @@
 #include <grpc/support/port_platform.h>
 #include <grpc/support/string_util.h>

+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/slice/percent_encoding.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"

 /** a size_t default value... maps to all 1's */
 #define NOT_SET (~(size_t)0)
--- a/src/core/ext/filters/http/client/http_client_filter.cc
+++ b/src/core/ext/filters/http/client/http_client_filter.cc
@ -20,12 +20,12 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 #include <string.h>
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/b64.h"
 #include "src/core/lib/slice/percent_encoding.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/transport_impl.h"

@ -35,7 +35,8 @@
 /* default maximum size of payload eligable for GET request */
 static const size_t kMaxPayloadSizeForGet = 2048;

-typedef struct call_data {
+namespace {
+struct call_data {
  grpc_call_combiner* call_combiner;
  // State for handling send_initial_metadata ops.
  grpc_linked_mdelem method;
@ -60,13 +61,14 @@ typedef struct call_data {
  grpc_closure on_send_message_next_done;
  grpc_closure* original_send_message_on_complete;
  grpc_closure send_message_on_complete;
-} call_data;
+};

-typedef struct channel_data {
+struct channel_data {
  grpc_mdelem static_scheme;
  grpc_mdelem user_agent;
  size_t max_payload_size_for_get;
-} channel_data;
+};
+}  // namespace

 static grpc_error* client_filter_incoming_metadata(grpc_call_element* elem,
                                                   grpc_metadata_batch* b) {
--- a/src/core/ext/filters/http/message_compress/message_compress_filter.cc
+++ b/src/core/ext/filters/http/message_compress/message_compress_filter.cc
@ -28,23 +28,24 @@
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/compression/algorithm_metadata.h"
 #include "src/core/lib/compression/message_compress.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/transport/static_metadata.h"

-typedef enum {
+namespace {
+enum initial_metadata_state {
  // Initial metadata not yet seen.
  INITIAL_METADATA_UNSEEN = 0,
  // Initial metadata seen; compression algorithm set.
  HAS_COMPRESSION_ALGORITHM,
  // Initial metadata seen; no compression algorithm set.
  NO_COMPRESSION_ALGORITHM,
-} initial_metadata_state;
+};

-typedef struct call_data {
+struct call_data {
  grpc_call_combiner* call_combiner;
  grpc_linked_mdelem compression_algorithm_storage;
  grpc_linked_mdelem stream_compression_algorithm_storage;
@ -62,9 +63,9 @@ typedef struct call_data {
  grpc_closure* original_send_message_on_complete;
  grpc_closure send_message_on_complete;
  grpc_closure on_send_message_next_done;
-} call_data;
+};

-typedef struct channel_data {
+struct channel_data {
  /** The default, channel-level, compression algorithm */
  grpc_compression_algorithm default_compression_algorithm;
  /** Bitset of enabled algorithms */
@ -78,7 +79,8 @@ typedef struct channel_data {
  uint32_t enabled_stream_compression_algorithms_bitset;
  /** Supported stream compression algorithms */
  uint32_t supported_stream_compression_algorithms;
-} channel_data;
+};
+}  // namespace

 static bool skip_compression(grpc_call_element* elem, uint32_t flags,
                             bool has_compression_algorithm) {
--- a/src/core/ext/filters/http/server/http_server_filter.cc
+++ b/src/core/ext/filters/http/server/http_server_filter.cc
@ -31,7 +31,8 @@
 #define EXPECTED_CONTENT_TYPE "application/grpc"
 #define EXPECTED_CONTENT_TYPE_LENGTH sizeof(EXPECTED_CONTENT_TYPE) - 1

-typedef struct call_data {
+namespace {
+struct call_data {
  grpc_call_combiner* call_combiner;

  grpc_linked_mdelem status;
@ -60,11 +61,12 @@ typedef struct call_data {
  grpc_closure hs_on_recv;
  grpc_closure hs_on_complete;
  grpc_closure hs_recv_message_ready;
-} call_data;
+};

-typedef struct channel_data {
+struct channel_data {
  uint8_t unused;
-} channel_data;
+};
+}  // namespace

 static grpc_error* server_filter_outgoing_metadata(grpc_call_element* elem,
                                                   grpc_metadata_batch* b) {
--- a/src/core/ext/filters/load_reporting/server_load_reporting_filter.cc
+++ b/src/core/ext/filters/load_reporting/server_load_reporting_filter.cc
@ -31,7 +31,8 @@
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/transport/static_metadata.h"

-typedef struct call_data {
+namespace {
+struct call_data {
  intptr_t id; /**< an id unique to the call */
  bool have_trailing_md_string;
  grpc_slice trailing_md_string;
@ -48,11 +49,12 @@ typedef struct call_data {
  /* to get notified of the availability of the incoming initial metadata. */
  grpc_closure on_initial_md_ready;
  grpc_metadata_batch* recv_initial_metadata;
-} call_data;
+};

-typedef struct channel_data {
+struct channel_data {
  intptr_t id; /**< an id unique to the channel */
-} channel_data;
+};
+}  // namespace

 static void on_initial_md_ready(void* user_data, grpc_error* err) {
  grpc_call_element* elem = (grpc_call_element*)user_data;
--- a/src/core/ext/filters/max_age/max_age_filter.cc
+++ b/src/core/ext/filters/max_age/max_age_filter.cc
@ -37,7 +37,8 @@
 #define MAX_CONNECTION_IDLE_INTEGER_OPTIONS \
  { DEFAULT_MAX_CONNECTION_IDLE_MS, 1, INT_MAX }

-typedef struct channel_data {
+namespace {
+struct channel_data {
  /* We take a reference to the channel stack for the timer callback */
  grpc_channel_stack* channel_stack;
  /* Guards access to max_age_timer, max_age_timer_pending, max_age_grace_timer
@ -84,7 +85,8 @@ typedef struct channel_data {
  grpc_connectivity_state connectivity_state;
  /* Number of active calls */
  gpr_atm call_count;
-} channel_data;
+};
+}  // namespace

 /* Increase the nubmer of active calls. Before the increasement, if there are no
   calls, the max_idle_timer should be cancelled. */
--- a/src/core/ext/filters/message_size/message_size_filter.cc
+++ b/src/core/ext/filters/message_size/message_size_filter.cc
@ -26,7 +26,7 @@

 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/channel_stack_builder.h"
-#include "src/core/lib/support/string.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/surface/channel_init.h"
 #include "src/core/lib/transport/service_config.h"

@ -86,7 +86,8 @@ static void* refcounted_message_size_limits_create_from_json(
  return value;
 }

-typedef struct call_data {
+namespace {
+struct call_data {
  grpc_call_combiner* call_combiner;
  message_size_limits limits;
  // Receive closures are chained: we inject this closure as the
@ -97,13 +98,14 @@ typedef struct call_data {
  grpc_byte_stream** recv_message;
  // Original recv_message_ready callback, invoked after our own.
  grpc_closure* next_recv_message_ready;
-} call_data;
+};

-typedef struct channel_data {
+struct channel_data {
  message_size_limits limits;
  // Maps path names to refcounted_message_size_limits structs.
  grpc_slice_hash_table* method_limit_table;
-} channel_data;
+};
+}  // namespace

 // Callback invoked when we receive a message.  Here we check the max
 // receive message size.
--- a/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.cc
+++ b/src/core/ext/filters/workarounds/workaround_cronet_compression_filter.cc
@ -25,7 +25,8 @@
 #include "src/core/lib/surface/channel_init.h"
 #include "src/core/lib/transport/metadata.h"

-typedef struct call_data {
+namespace {
+struct call_data {
  // Receive closures are chained: we inject this closure as the
  // recv_initial_metadata_ready up-call on transport_stream_op, and remember to
  // call our next_recv_initial_metadata_ready member after handling it.
@ -37,7 +38,8 @@ typedef struct call_data {

  // Marks whether the workaround is active
  bool workaround_active;
-} call_data;
+};
+}  // namespace

 // Find the user agent metadata element in the batch
 static bool get_user_agent_mdelem(const grpc_metadata_batch* batch,
--- a/src/core/ext/transport/chttp2/transport/bin_decoder.cc
+++ b/src/core/ext/transport/chttp2/transport/bin_decoder.cc
@ -19,9 +19,9 @@
 #include "src/core/ext/transport/chttp2/transport/bin_decoder.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"

 static uint8_t decode_table[] = {
    0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,
--- a/src/core/ext/transport/chttp2/transport/chttp2_plugin.cc
+++ b/src/core/ext/transport/chttp2/transport/chttp2_plugin.cc
@ -18,8 +18,16 @@

 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/gpr/env.h"
 #include "src/core/lib/transport/metadata.h"

-void grpc_chttp2_plugin_init(void) {}
+void grpc_chttp2_plugin_init(void) {
+  g_flow_control_enabled = true;
+  char* env_variable = gpr_getenv("GRPC_EXPERIMENTAL_DISABLE_FLOW_CONTROL");
+  if (env_variable != nullptr) {
+    g_flow_control_enabled = false;
+    gpr_free(env_variable);
+  }
+}

 void grpc_chttp2_plugin_shutdown(void) {}
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.cc
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.cc
@ -38,14 +38,14 @@
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/compression/stream_compression.h"
 #include "src/core/lib/debug/stats.h"
+#include "src/core/lib/gpr/env.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/http/parser.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/env.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/error_utils.h"
 #include "src/core/lib/transport/http2_errors.h"
 #include "src/core/lib/transport/static_metadata.h"
@ -152,6 +152,10 @@ static void keepalive_watchdog_fired_locked(void* arg, grpc_error* error);

 static void reset_byte_stream(void* arg, grpc_error* error);

+// Flow control default enabled. Can be disabled by setting
+// GRPC_EXPERIMENTAL_DISABLE_FLOW_CONTROL
+bool g_flow_control_enabled = true;
+
 /*******************************************************************************
 * CONSTRUCTION/DESTRUCTION/REFCOUNTING
 */
@ -517,7 +521,13 @@ static void init_transport(grpc_chttp2_transport* t,
    }
  }

-  t->flow_control.Init(t, enable_bdp);
+  if (g_flow_control_enabled) {
+    t->flow_control.Init<grpc_core::chttp2::TransportFlowControl>(t,
+                                                                  enable_bdp);
+  } else {
+    t->flow_control.Init<grpc_core::chttp2::TransportFlowControlDisabled>(t);
+    enable_bdp = false;
+  }

  /* No pings allowed before receiving a header or data frame. */
  t->ping_state.pings_before_data_required = 0;
@ -682,7 +692,14 @@ static int init_stream(grpc_transport* gt, grpc_stream* gs,
    post_destructive_reclaimer(t);
  }

-  s->flow_control.Init(t->flow_control.get(), s);
+  if (t->flow_control->flow_control_enabled()) {
+    s->flow_control.Init<grpc_core::chttp2::StreamFlowControl>(
+        static_cast<grpc_core::chttp2::TransportFlowControl*>(
+            t->flow_control.get()),
+        s);
+  } else {
+    s->flow_control.Init<grpc_core::chttp2::StreamFlowControlDisabled>();
+  }
  GPR_TIMER_END("init_stream", 0);

  return 0;
@ -2402,8 +2419,11 @@ static void read_action_locked(void* tp, grpc_error* error) {
    grpc_error* errors[3] = {GRPC_ERROR_REF(error), GRPC_ERROR_NONE,
                             GRPC_ERROR_NONE};
    for (; i < t->read_buffer.count && errors[1] == GRPC_ERROR_NONE; i++) {
-      t->flow_control->bdp_estimator()->AddIncomingBytes(
-          (int64_t)GRPC_SLICE_LENGTH(t->read_buffer.slices[i]));
+      grpc_core::BdpEstimator* bdp_est = t->flow_control->bdp_estimator();
+      if (bdp_est) {
+        bdp_est->AddIncomingBytes(
+            (int64_t)GRPC_SLICE_LENGTH(t->read_buffer.slices[i]));
+      }
      errors[1] = grpc_chttp2_perform_read(t, t->read_buffer.slices[i]);
    }
    if (errors[1] != GRPC_ERROR_NONE) {
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.h
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.h
@ -27,6 +27,8 @@ extern grpc_core::TraceFlag grpc_http_trace;
 extern grpc_core::TraceFlag grpc_trace_http2_stream_state;
 extern grpc_core::DebugOnlyTraceFlag grpc_trace_chttp2_refcount;

+extern bool g_flow_control_enabled;
+
 grpc_transport* grpc_create_chttp2_transport(
    const grpc_channel_args* channel_args, grpc_endpoint* ep, bool is_client);

--- a/src/core/ext/transport/chttp2/transport/flow_control.cc
+++ b/src/core/ext/transport/chttp2/transport/flow_control.cc
@ -29,7 +29,7 @@
 #include <grpc/support/useful.h>

 #include "src/core/ext/transport/chttp2/transport/internal.h"
-#include "src/core/lib/support/string.h"
+#include "src/core/lib/gpr/string.h"

 grpc_core::TraceFlag grpc_flowctl_trace(false, "flowctl");

@ -149,6 +149,25 @@ void FlowControlAction::Trace(grpc_chttp2_transport* t) const {
  gpr_free(mf_str);
 }

+TransportFlowControlDisabled::TransportFlowControlDisabled(
+    grpc_chttp2_transport* t) {
+  remote_window_ = kMaxWindow;
+  target_initial_window_size_ = kMaxWindow;
+  announced_window_ = kMaxWindow;
+  t->settings[GRPC_PEER_SETTINGS][GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE] =
+      kFrameSize;
+  t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE] =
+      kFrameSize;
+  t->settings[GRPC_ACKED_SETTINGS][GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE] =
+      kFrameSize;
+  t->settings[GRPC_PEER_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE] =
+      kMaxWindow;
+  t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE] =
+      kMaxWindow;
+  t->settings[GRPC_ACKED_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE] =
+      kMaxWindow;
+}
+
 TransportFlowControl::TransportFlowControl(const grpc_chttp2_transport* t,
                                           bool enable_bdp_probe)
    : t_(t),
@ -318,7 +337,7 @@ double TransportFlowControl::SmoothLogBdp(double value) {
 }

 FlowControlAction::Urgency TransportFlowControl::DeltaUrgency(
-    int32_t value, grpc_chttp2_setting_id setting_id) {
+    int64_t value, grpc_chttp2_setting_id setting_id) {
  int64_t delta =
      (int64_t)value - (int64_t)t_->settings[GRPC_LOCAL_SETTINGS][setting_id];
  // TODO(ncteisen): tune this
@ -344,7 +363,7 @@ FlowControlAction TransportFlowControl::PeriodicUpdate() {
    action.set_send_initial_window_update(
        DeltaUrgency(target_initial_window_size_,
                     GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE),
-        target_initial_window_size_);
+        (uint32_t)target_initial_window_size_);

    // get bandwidth estimate and update max_frame accordingly.
    double bw_dbl = bdp_estimator_.EstimateBandwidth();
@ -354,7 +373,7 @@ FlowControlAction TransportFlowControl::PeriodicUpdate() {
                target_initial_window_size_),
        16384, 16777215);
    action.set_send_max_frame_size_update(
-        DeltaUrgency(frame_size, GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE),
+        DeltaUrgency((int64_t)frame_size, GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE),
        frame_size);
  }
  return UpdateAction(action);
--- a/src/core/ext/transport/chttp2/transport/flow_control.h
+++ b/src/core/ext/transport/chttp2/transport/flow_control.h
@ -24,7 +24,8 @@

 #include <grpc/support/useful.h>
 #include "src/core/ext/transport/chttp2/transport/http2_settings.h"
-#include "src/core/lib/support/manual_constructor.h"
+#include "src/core/lib/gprpp/abstract.h"
+#include "src/core/lib/gprpp/manual_constructor.h"
 #include "src/core/lib/transport/bdp_estimator.h"
 #include "src/core/lib/transport/pid_controller.h"

@ -43,10 +44,16 @@ namespace grpc_core {
 namespace chttp2 {

 static constexpr uint32_t kDefaultWindow = 65535;
+static constexpr int64_t kMaxWindow = (int64_t)((1u << 31) - 1);
+// TODO(ncteisen): Tune this
+static constexpr uint32_t kFrameSize = 1024 * 1024;

 class TransportFlowControl;
 class StreamFlowControl;

+// Encapsulates a collections of actions the transport needs to take with
+// regard to flow control. Each action comes with urgencies that tell the
+// transport how quickly the action must take place.
 class FlowControlAction {
 public:
  enum class Urgency : uint8_t {
@ -132,36 +139,122 @@ class FlowControlTrace {
  int64_t announced_window_delta_;
 };

-class TransportFlowControl {
+// Fat interface with all methods a flow control implementation needs to
+// support. gRPC C Core does not support pure virtual functions, so instead
+// we abort in any methods which require implementation in the base class.
+class TransportFlowControlBase {
+ public:
+  TransportFlowControlBase() {}
+  virtual ~TransportFlowControlBase() {}
+
+  // Is flow control enabled? This is needed in other codepaths like the checks
+  // in parsing and in writing.
+  virtual bool flow_control_enabled() const { abort(); }
+
+  // Called to check if the transport needs to send a WINDOW_UPDATE frame
+  virtual uint32_t MaybeSendUpdate(bool writing_anyway) { abort(); }
+
+  // Using the protected members, returns and Action to be taken by the
+  // tranport.
+  virtual FlowControlAction MakeAction() { abort(); }
+
+  // Using the protected members, returns and Action to be taken by the
+  // tranport. Also checks for updates to our BDP estimate and acts
+  // accordingly.
+  virtual FlowControlAction PeriodicUpdate() { abort(); }
+
+  // Called to do bookkeeping when a stream owned by this transport sends
+  // data on the wire
+  virtual void StreamSentData(int64_t size) { abort(); }
+
+  // Called to do bookkeeping when a stream owned by this transport receives
+  // data from the wire. Also does error checking for frame size.
+  virtual grpc_error* RecvData(int64_t incoming_frame_size) { abort(); }
+
+  // Called to do bookkeeping when we receive a WINDOW_UPDATE frame.
+  virtual void RecvUpdate(uint32_t size) { abort(); }
+
+  // Returns the BdpEstimator held by this object. Caller is responsible for
+  // checking for nullptr. TODO(ncteisen): consider fully encapsulating all
+  // bdp estimator actions inside TransportFlowControl
+  virtual BdpEstimator* bdp_estimator() { return nullptr; }
+
+  // Getters
+  int64_t remote_window() const { return remote_window_; }
+  virtual int64_t target_window() const { return target_initial_window_size_; }
+  int64_t announced_window() const { return announced_window_; }
+
+  // Used in certain benchmarks in which we don't want FlowControl to be a
+  // factor
+  virtual void TestOnlyForceHugeWindow() {}
+
+  GRPC_ABSTRACT_BASE_CLASS
+
+ protected:
+  friend class ::grpc::testing::TrickledCHTTP2;
+  int64_t remote_window_ = kDefaultWindow;
+  int64_t target_initial_window_size_ = kDefaultWindow;
+  int64_t announced_window_ = kDefaultWindow;
+};
+
+// Implementation of flow control that does NOTHING. Always returns maximum
+// values, never initiates writes, and assumes that the remote peer is doing
+// the same. To be used to narrow down on flow control as the cause of negative
+// performance.
+class TransportFlowControlDisabled final : public TransportFlowControlBase {
+ public:
+  // Maxes out all values
+  TransportFlowControlDisabled(grpc_chttp2_transport* t);
+
+  bool flow_control_enabled() const override { return false; }
+
+  // Never do anything.
+  uint32_t MaybeSendUpdate(bool writing_anyway) override { return 0; }
+  FlowControlAction MakeAction() override { return FlowControlAction(); }
+  FlowControlAction PeriodicUpdate() override { return FlowControlAction(); }
+  void StreamSentData(int64_t size) override {}
+  grpc_error* RecvData(int64_t incoming_frame_size) override {
+    return GRPC_ERROR_NONE;
+  }
+  void RecvUpdate(uint32_t size) override {}
+};
+
+// Implementation of flow control that abides to HTTP/2 spec and attempts
+// to be as performant as possible.
+class TransportFlowControl final : public TransportFlowControlBase {
 public:
  TransportFlowControl(const grpc_chttp2_transport* t, bool enable_bdp_probe);
  ~TransportFlowControl() {}

+  bool flow_control_enabled() const override { return true; }
+
  bool bdp_probe() const { return enable_bdp_probe_; }

  // returns an announce if we should send a transport update to our peer,
  // else returns zero; writing_anyway indicates if a write would happen
  // regardless of the send - if it is false and this function returns non-zero,
  // this announce will cause a write to occur
-  uint32_t MaybeSendUpdate(bool writing_anyway);
+  uint32_t MaybeSendUpdate(bool writing_anyway) override;

  // Reads the flow control data and returns and actionable struct that will
  // tell chttp2 exactly what it needs to do
-  FlowControlAction MakeAction() { return UpdateAction(FlowControlAction()); }
+  FlowControlAction MakeAction() override {
+    return UpdateAction(FlowControlAction());
+  }

  // Call periodically (at a low-ish rate, 100ms - 10s makes sense)
  // to perform more complex flow control calculations and return an action
  // to let chttp2 change its parameters
-  FlowControlAction PeriodicUpdate();
+  FlowControlAction PeriodicUpdate() override;

-  void StreamSentData(int64_t size) { remote_window_ -= size; }
+  void StreamSentData(int64_t size) override { remote_window_ -= size; }

  grpc_error* ValidateRecvData(int64_t incoming_frame_size);
  void CommitRecvData(int64_t incoming_frame_size) {
    announced_window_ -= incoming_frame_size;
  }

-  grpc_error* RecvData(int64_t incoming_frame_size) {
+  grpc_error* RecvData(int64_t incoming_frame_size) override {
    FlowControlTrace trace("  data recv", this, nullptr);
    grpc_error* error = ValidateRecvData(incoming_frame_size);
    if (error != GRPC_ERROR_NONE) return error;
@ -170,18 +263,18 @@ class TransportFlowControl {
  }

  // we have received a WINDOW_UPDATE frame for a transport
-  void RecvUpdate(uint32_t size) {
+  void RecvUpdate(uint32_t size) override {
    FlowControlTrace trace("t updt recv", this, nullptr);
    remote_window_ += size;
  }

-  int64_t remote_window() const { return remote_window_; }
-  int64_t target_window() const {
+  // See comment above announced_stream_total_over_incoming_window_ for the
+  // logic behind this decision.
+  int64_t target_window() const override {
    return (uint32_t)GPR_MIN((int64_t)((1u << 31) - 1),
                             announced_stream_total_over_incoming_window_ +
                                 target_initial_window_size_);
  }
-  int64_t announced_window() const { return announced_window_; }

  const grpc_chttp2_transport* transport() const { return t_; }

@ -201,18 +294,17 @@ class TransportFlowControl {
    }
  }

-  BdpEstimator* bdp_estimator() { return &bdp_estimator_; }
+  BdpEstimator* bdp_estimator() override { return &bdp_estimator_; }

-  void TestOnlyForceHugeWindow() {
+  void TestOnlyForceHugeWindow() override {
    announced_window_ = 1024 * 1024 * 1024;
    remote_window_ = 1024 * 1024 * 1024;
  }

 private:
-  friend class ::grpc::testing::TrickledCHTTP2;
  double TargetLogBdp();
  double SmoothLogBdp(double value);
-  FlowControlAction::Urgency DeltaUrgency(int32_t value,
+  FlowControlAction::Urgency DeltaUrgency(int64_t value,
                                          grpc_chttp2_setting_id setting_id);

  FlowControlAction UpdateAction(FlowControlAction action) {
@ -225,9 +317,6 @@ class TransportFlowControl {

  const grpc_chttp2_transport* const t_;

-  /** Our bookkeeping for the remote peer's available window */
-  int64_t remote_window_ = kDefaultWindow;
-
  /** calculating what we should give for local window:
      we track the total amount of flow control over initial window size
      across all streams: this is data that we want to receive right now (it
@ -239,13 +328,6 @@ class TransportFlowControl {
  int64_t announced_stream_total_over_incoming_window_ = 0;
  int64_t announced_stream_total_under_incoming_window_ = 0;

-  /** This is out window according to what we have sent to our remote peer. The
-   * difference between this and target window is what we use to decide when
-   * to send WINDOW_UPDATE frames. */
-  int64_t announced_window_ = kDefaultWindow;
-
-  int32_t target_initial_window_size_ = kDefaultWindow;
-
  /** should we probe bdp? */
  const bool enable_bdp_probe_;

@ -257,39 +339,117 @@ class TransportFlowControl {
  grpc_millis last_pid_update_ = 0;
 };

-class StreamFlowControl {
+// Fat interface with all methods a stream flow control implementation needs
+// to support. gRPC C Core does not support pure virtual functions, so instead
+// we abort in any methods which require implementation in the base class.
+class StreamFlowControlBase {
+ public:
+  StreamFlowControlBase() {}
+  virtual ~StreamFlowControlBase() {}
+
+  // Updates an action using the protected members.
+  virtual FlowControlAction UpdateAction(FlowControlAction action) { abort(); }
+
+  // Using the protected members, returns an Action for this stream to be
+  // taken by the tranport.
+  virtual FlowControlAction MakeAction() { abort(); }
+
+  // Bookkeeping for when data is sent on this stream.
+  virtual void SentData(int64_t outgoing_frame_size) { abort(); }
+
+  // Bookkeeping and error checking for when data is received by this stream.
+  virtual grpc_error* RecvData(int64_t incoming_frame_size) { abort(); }
+
+  // Called to check if this stream needs to send a WINDOW_UPDATE frame.
+  virtual uint32_t MaybeSendUpdate() { abort(); }
+
+  // Bookkeeping for receiving a WINDOW_UPDATE from for this stream.
+  virtual void RecvUpdate(uint32_t size) { abort(); }
+
+  // Bookkeeping for when a call pulls bytes out of the transport. At this
+  // point we consider the data 'used' and can thus let out peer know we are
+  // ready for more data.
+  virtual void IncomingByteStreamUpdate(size_t max_size_hint,
+                                        size_t have_already) {
+    abort();
+  }
+
+  // Used in certain benchmarks in which we don't want FlowControl to be a
+  // factor
+  virtual void TestOnlyForceHugeWindow() {}
+
+  // Getters
+  int64_t remote_window_delta() { return remote_window_delta_; }
+  int64_t local_window_delta() { return local_window_delta_; }
+  int64_t announced_window_delta() { return announced_window_delta_; }
+
+  GRPC_ABSTRACT_BASE_CLASS
+
+ protected:
+  friend class ::grpc::testing::TrickledCHTTP2;
+  int64_t remote_window_delta_ = 0;
+  int64_t local_window_delta_ = 0;
+  int64_t announced_window_delta_ = 0;
+};
+
+// Implementation of flow control that does NOTHING. Always returns maximum
+// values, never initiates writes, and assumes that the remote peer is doing
+// the same. To be used to narrow down on flow control as the cause of negative
+// performance.
+class StreamFlowControlDisabled : public StreamFlowControlBase {
+ public:
+  FlowControlAction UpdateAction(FlowControlAction action) override {
+    return action;
+  }
+  FlowControlAction MakeAction() override { return FlowControlAction(); }
+  void SentData(int64_t outgoing_frame_size) override {}
+  grpc_error* RecvData(int64_t incoming_frame_size) override {
+    return GRPC_ERROR_NONE;
+  }
+  uint32_t MaybeSendUpdate() override { return 0; }
+  void RecvUpdate(uint32_t size) override {}
+  void IncomingByteStreamUpdate(size_t max_size_hint,
+                                size_t have_already) override {}
+};
+
+// Implementation of flow control that abides to HTTP/2 spec and attempts
+// to be as performant as possible.
+class StreamFlowControl final : public StreamFlowControlBase {
 public:
  StreamFlowControl(TransportFlowControl* tfc, const grpc_chttp2_stream* s);
  ~StreamFlowControl() {
    tfc_->PreUpdateAnnouncedWindowOverIncomingWindow(announced_window_delta_);
  }

-  FlowControlAction UpdateAction(FlowControlAction action);
-  FlowControlAction MakeAction() { return UpdateAction(tfc_->MakeAction()); }
+  FlowControlAction UpdateAction(FlowControlAction action) override;
+  FlowControlAction MakeAction() override {
+    return UpdateAction(tfc_->MakeAction());
+  }

  // we have sent data on the wire, we must track this in our bookkeeping for
  // the remote peer's flow control.
-  void SentData(int64_t outgoing_frame_size) {
+  void SentData(int64_t outgoing_frame_size) override {
    FlowControlTrace tracer("  data sent", tfc_, this);
    tfc_->StreamSentData(outgoing_frame_size);
    remote_window_delta_ -= outgoing_frame_size;
  }

  // we have received data from the wire
-  grpc_error* RecvData(int64_t incoming_frame_size);
+  grpc_error* RecvData(int64_t incoming_frame_size) override;

  // returns an announce if we should send a stream update to our peer, else
  // returns zero
-  uint32_t MaybeSendUpdate();
+  uint32_t MaybeSendUpdate() override;

  // we have received a WINDOW_UPDATE frame for a stream
-  void RecvUpdate(uint32_t size) {
+  void RecvUpdate(uint32_t size) override {
    FlowControlTrace trace("s updt recv", tfc_, this);
    remote_window_delta_ += size;
  }

  // the application is asking for a certain amount of bytes
-  void IncomingByteStreamUpdate(size_t max_size_hint, size_t have_already);
+  void IncomingByteStreamUpdate(size_t max_size_hint,
+                                size_t have_already) override;

  int64_t remote_window_delta() const { return remote_window_delta_; }
  int64_t local_window_delta() const { return local_window_delta_; }
@ -297,14 +457,13 @@ class StreamFlowControl {

  const grpc_chttp2_stream* stream() const { return s_; }

-  void TestOnlyForceHugeWindow() {
+  void TestOnlyForceHugeWindow() override {
    announced_window_delta_ = 1024 * 1024 * 1024;
    local_window_delta_ = 1024 * 1024 * 1024;
    remote_window_delta_ = 1024 * 1024 * 1024;
  }

 private:
-  friend class ::grpc::testing::TrickledCHTTP2;
  TransportFlowControl* const tfc_;
  const grpc_chttp2_stream* const s_;

@ -313,21 +472,6 @@ class StreamFlowControl {
    announced_window_delta_ += change;
    tfc->PostUpdateAnnouncedWindowOverIncomingWindow(announced_window_delta_);
  }
-
-  /** window available for us to send to peer, over or under the initial
-   * window
-   * size of the transport... ie:
-   * remote_window = remote_window_delta + transport.initial_window_size */
-  int64_t remote_window_delta_ = 0;
-
-  /** window available for peer to send to us (as a delta on
-   * transport.initial_window_size)
-   * local_window = local_window_delta + transport.initial_window_size */
-  int64_t local_window_delta_ = 0;
-
-  /** window available for peer to send to us over this stream that we have
-   * announced to the peer */
-  int64_t announced_window_delta_ = 0;
 };

 }  // namespace chttp2
--- a/src/core/ext/transport/chttp2/transport/frame_data.cc
+++ b/src/core/ext/transport/chttp2/transport/frame_data.cc
@ -25,9 +25,9 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 #include "src/core/ext/transport/chttp2/transport/internal.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/transport.h"

 grpc_error* grpc_chttp2_data_parser_init(grpc_chttp2_data_parser* parser) {
--- a/src/core/ext/transport/chttp2/transport/frame_settings.cc
+++ b/src/core/ext/transport/chttp2/transport/frame_settings.cc
@ -186,6 +186,12 @@ grpc_error* grpc_chttp2_settings_parser_parse(void* p, grpc_chttp2_transport* t,
        if (grpc_wire_id_to_setting_id(parser->id, &id)) {
          const grpc_chttp2_setting_parameters* sp =
              &grpc_chttp2_settings_parameters[id];
+          // If flow control is disabled we skip these.
+          if (!t->flow_control->flow_control_enabled() &&
+              (id == GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE ||
+               id == GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE)) {
+            continue;
+          }
          if (parser->value < sp->min_value || parser->value > sp->max_value) {
            switch (sp->invalid_value_behavior) {
              case GRPC_CHTTP2_CLAMP_INVALID_VALUE:
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.cc
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.cc
@ -31,10 +31,10 @@

 #include "src/core/ext/transport/chttp2/transport/bin_encoder.h"
 #include "src/core/lib/debug/stats.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/http2_errors.h"

 typedef enum {
--- a/src/core/ext/transport/chttp2/transport/hpack_table.cc
+++ b/src/core/ext/transport/chttp2/transport/hpack_table.cc
@ -26,7 +26,7 @@
 #include <grpc/support/string_util.h>

 #include "src/core/lib/debug/trace.h"
-#include "src/core/lib/support/murmur_hash.h"
+#include "src/core/lib/gpr/murmur_hash.h"

 extern grpc_core::TraceFlag grpc_http_trace;

--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@ -35,10 +35,10 @@
 #include "src/core/ext/transport/chttp2/transport/incoming_metadata.h"
 #include "src/core/ext/transport/chttp2/transport/stream_map.h"
 #include "src/core/lib/compression/stream_compression.h"
+#include "src/core/lib/gprpp/manual_constructor.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/timer.h"
-#include "src/core/lib/support/manual_constructor.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/transport_impl.h"

@ -351,7 +351,10 @@ struct grpc_chttp2_transport {
  /** parser for goaway frames */
  grpc_chttp2_goaway_parser goaway_parser;

-  grpc_core::ManualConstructor<grpc_core::chttp2::TransportFlowControl>
+  grpc_core::PolymorphicManualConstructor<
+      grpc_core::chttp2::TransportFlowControlBase,
+      grpc_core::chttp2::TransportFlowControl,
+      grpc_core::chttp2::TransportFlowControlDisabled>
      flow_control;
  /** initial window change. This is tracked as we parse settings frames from
   * the remote peer. If there is a positive delta, then we will make all
@ -525,7 +528,10 @@ struct grpc_chttp2_stream {
  bool sent_initial_metadata;
  bool sent_trailing_metadata;

-  grpc_core::ManualConstructor<grpc_core::chttp2::StreamFlowControl>
+  grpc_core::PolymorphicManualConstructor<
+      grpc_core::chttp2::StreamFlowControlBase,
+      grpc_core::chttp2::StreamFlowControl,
+      grpc_core::chttp2::StreamFlowControlDisabled>
      flow_control;

  grpc_slice_buffer flow_controlled_buffer;
--- a/src/core/ext/transport/chttp2/transport/parsing.cc
+++ b/src/core/ext/transport/chttp2/transport/parsing.cc
@ -186,9 +186,10 @@ grpc_error* grpc_chttp2_perform_read(grpc_chttp2_transport* t,
          return GRPC_ERROR_NONE;
        }
        goto dts_fh_0; /* loop */
-      } else if (t->incoming_frame_size >
-                 t->settings[GRPC_ACKED_SETTINGS]
-                            [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE]) {
+      } else if (t->flow_control->flow_control_enabled() &&
+                 t->incoming_frame_size >
+                     t->settings[GRPC_ACKED_SETTINGS]
+                                [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE]) {
        char* msg;
        gpr_asprintf(&msg, "Frame size %d is larger than max frame size %d",
                     t->incoming_frame_size,
--- a/src/core/ext/transport/chttp2/transport/stream_lists.cc
+++ b/src/core/ext/transport/chttp2/transport/stream_lists.cc
@ -183,6 +183,7 @@ void grpc_chttp2_list_remove_waiting_for_concurrency(grpc_chttp2_transport* t,

 void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport* t,
                                               grpc_chttp2_stream* s) {
+  GPR_ASSERT(t->flow_control->flow_control_enabled());
  stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }

@ -198,6 +199,7 @@ void grpc_chttp2_list_remove_stalled_by_transport(grpc_chttp2_transport* t,

 void grpc_chttp2_list_add_stalled_by_stream(grpc_chttp2_transport* t,
                                            grpc_chttp2_stream* s) {
+  GPR_ASSERT(t->flow_control->flow_control_enabled());
  stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
 }

--- a/src/core/ext/transport/chttp2/transport/writing.cc
+++ b/src/core/ext/transport/chttp2/transport/writing.cc
@ -138,10 +138,11 @@ static void report_stall(grpc_chttp2_transport* t, grpc_chttp2_stream* s,
                         const char* staller) {
  gpr_log(
      GPR_DEBUG,
-      "%s:%p stream %d stalled by %s [fc:pending=%" PRIdPTR ":flowed=%" PRId64
+      "%s:%p stream %d stalled by %s [fc:pending=%" PRIdPTR
+      ":pending-compressed=%" PRIdPTR ":flowed=%" PRId64
      ":peer_initwin=%d:t_win=%" PRId64 ":s_win=%d:s_delta=%" PRId64 "]",
      t->peer_string, t, s->id, staller, s->flow_controlled_buffer.length,
-      s->flow_controlled_bytes_flowed,
+      s->compressed_data_buffer.length, s->flow_controlled_bytes_flowed,
      t->settings[GRPC_ACKED_SETTINGS]
                 [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE],
      t->flow_control->remote_window(),
--- a/src/core/ext/transport/cronet/transport/cronet_transport.cc
+++ b/src/core/ext/transport/cronet/transport/cronet_transport.cc
@ -28,11 +28,11 @@

 #include "src/core/ext/transport/chttp2/transport/incoming_metadata.h"
 #include "src/core/ext/transport/cronet/transport/cronet_transport.h"
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/metadata_batch.h"
 #include "src/core/lib/transport/static_metadata.h"
--- a/src/core/lib/backoff/backoff.cc
+++ b/src/core/lib/backoff/backoff.cc
@ -41,18 +41,20 @@ double generate_uniform_random_number_between(uint32_t* rng_state, double a,
  const double range = b - a;
  return a + generate_uniform_random_number(rng_state) * range;
 }
-}  // namespace

-BackOff::BackOff(const Options& options) : options_(options) {
-  rng_state_ = static_cast<uint32_t>(gpr_now(GPR_CLOCK_REALTIME).tv_nsec);
-}
+}  // namespace

-grpc_millis BackOff::Begin() {
-  current_backoff_ = options_.initial_backoff();
-  return current_backoff_ + grpc_core::ExecCtx::Get()->Now();
+BackOff::BackOff(const Options& options)
+    : options_(options),
+      rng_state_(static_cast<uint32_t>(gpr_now(GPR_CLOCK_REALTIME).tv_nsec)) {
+  Reset();
 }

-grpc_millis BackOff::Step() {
+grpc_millis BackOff::NextAttemptTime() {
+  if (initial_) {
+    initial_ = false;
+    return current_backoff_ + grpc_core::ExecCtx::Get()->Now();
+  }
  current_backoff_ =
      (grpc_millis)(std::min(current_backoff_ * options_.multiplier(),
                             (double)options_.max_backoff()));
@ -63,7 +65,10 @@ grpc_millis BackOff::Step() {
  return next_timeout + grpc_core::ExecCtx::Get()->Now();
 }

-void BackOff::Reset() { current_backoff_ = options_.initial_backoff(); }
+void BackOff::Reset() {
+  current_backoff_ = options_.initial_backoff();
+  initial_ = true;
+}

 void BackOff::SetRandomSeed(uint32_t seed) { rng_state_ = seed; }

--- a/src/core/lib/backoff/backoff.h
+++ b/src/core/lib/backoff/backoff.h
@ -32,14 +32,11 @@ class BackOff {
  /// Initialize backoff machinery - does not need to be destroyed
  explicit BackOff(const Options& options);

-  /// Begin retry loop: returns the deadline to be used for the next attempt,
-  /// following the backoff strategy.
-  grpc_millis Begin();
-  /// Step a retry loop: returns the deadline to be used for the next attempt,
-  /// following the backoff strategy.
-  grpc_millis Step();
-  /// Reset the backoff, so the next grpc_backoff_step will be a
-  /// grpc_backoff_begin.
+  /// Returns the time at which the next attempt should start.
+  grpc_millis NextAttemptTime();
+
+  /// Reset the backoff, so the next value returned by NextAttemptTime()
+  /// will be the time of the second attempt (rather than the Nth).
  void Reset();

  void SetRandomSeed(unsigned int seed);
@ -80,9 +77,10 @@ class BackOff {

 private:
  const Options options_;
+  uint32_t rng_state_;
+  bool initial_;
  /// current delay before retries
  grpc_millis current_backoff_;
-  uint32_t rng_state_;
 };

 }  // namespace grpc_core
--- a/src/core/lib/channel/channel_args.cc
+++ b/src/core/lib/channel/channel_args.cc
@ -29,7 +29,7 @@
 #include <grpc/support/useful.h>

 #include "src/core/lib/channel/channel_args.h"
-#include "src/core/lib/support/string.h"
+#include "src/core/lib/gpr/string.h"

 static grpc_arg copy_arg(const grpc_arg* src) {
  grpc_arg dst;
--- a/src/core/lib/channel/channel_stack.h
+++ b/src/core/lib/channel/channel_stack.h
@ -40,9 +40,9 @@
 #include <grpc/support/time.h>

 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/gpr/arena.h"
 #include "src/core/lib/iomgr/call_combiner.h"
 #include "src/core/lib/iomgr/polling_entity.h"
-#include "src/core/lib/support/arena.h"
 #include "src/core/lib/transport/transport.h"

 typedef struct grpc_channel_element grpc_channel_element;
--- a/src/core/lib/channel/connected_channel.cc
+++ b/src/core/lib/channel/connected_channel.cc
@ -26,8 +26,8 @@
 #include <grpc/slice_buffer.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include "src/core/lib/gpr/string.h"
 #include "src/core/lib/profiling/timers.h"
-#include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/transport.h"

 #define MAX_BUFFER_LENGTH 8192
--- a/src/core/lib/debug/stats.cc
+++ b/src/core/lib/debug/stats.cc
@ -25,7 +25,7 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>

-#include "src/core/lib/support/string.h"
+#include "src/core/lib/gpr/string.h"

 grpc_stats_data* grpc_stats_per_cpu_storage = nullptr;
 static size_t g_num_cores;
--- a/src/core/lib/debug/trace.cc
+++ b/src/core/lib/debug/trace.cc
@ -23,7 +23,7 @@
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
-#include "src/core/lib/support/env.h"
+#include "src/core/lib/gpr/env.h"

 int grpc_tracer_set_enabled(const char* name, int enabled);

--- a/src/core/lib/gpr/README.md
+++ b/src/core/lib/gpr/README.md
@ -0,0 +1,8 @@
+# GPR - Google Portable Runtime for C
+
+The files in this directory contain basic utility code and platform
+abstractions for C code.  None of this code is gRPC-specific; anything
+here may also be useful for other open source projects written in C.
+
+Note that this is one of the few places in src/core where we allow
+the use of portability macros.
--- a/src/core/lib/support/alloc.cc
+++ b/src/core/lib/support/alloc.cc
--- a/src/core/lib/support/arena.cc
+++ b/src/core/lib/support/arena.cc
@ -16,7 +16,7 @@
 *
 */

-#include "src/core/lib/support/arena.h"
+#include "src/core/lib/gpr/arena.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/atm.h>
 #include <grpc/support/log.h>
--- a/src/core/lib/support/arena.h
+++ b/src/core/lib/support/arena.h
@ -22,8 +22,8 @@
 // Tracks the total memory allocated against it, so that future arenas can
 // pre-allocate the right amount of memory

-#ifndef GRPC_CORE_LIB_SUPPORT_ARENA_H
-#define GRPC_CORE_LIB_SUPPORT_ARENA_H
+#ifndef GRPC_CORE_LIB_GPR_ARENA_H
+#define GRPC_CORE_LIB_GPR_ARENA_H

 #include <stddef.h>

@ -36,4 +36,4 @@ void* gpr_arena_alloc(gpr_arena* arena, size_t size);
 // Destroy an arena, returning the total number of bytes allocated
 size_t gpr_arena_destroy(gpr_arena* arena);

-#endif /* GRPC_CORE_LIB_SUPPORT_ARENA_H */
+#endif /* GRPC_CORE_LIB_GPR_ARENA_H */
--- a/src/core/lib/support/atm.cc
+++ b/src/core/lib/support/atm.cc
--- a/src/core/lib/support/avl.cc
+++ b/src/core/lib/support/avl.cc
--- a/src/core/lib/support/cmdline.cc
+++ b/src/core/lib/support/cmdline.cc
@ -25,7 +25,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
-#include "src/core/lib/support/string.h"
+#include "src/core/lib/gpr/string.h"

 typedef enum { ARGTYPE_INT, ARGTYPE_BOOL, ARGTYPE_STRING } argtype;

--- a/src/core/lib/support/cpu_iphone.cc
+++ b/src/core/lib/support/cpu_iphone.cc
--- a/src/core/lib/support/cpu_linux.cc
+++ b/src/core/lib/support/cpu_linux.cc
--- a/Show More
+++ b/Show More