Add cc_proto_library and cc_grpc_library targets for Bigtable protos.

Also fix indentation of cc_grpc_library targets in Spanner and IAM protos.

PiperOrigin-RevId: 293440538

google/bigtable/admin/v2/BUILD.bazel

@@ -377,4 +377,19 @@ csharp_gapic_assembly_pkg(
 ##############################################################################
 # C++
 ##############################################################################
-# Put your C++ rules here
+load(
+    "@com_google_googleapis_imports//:imports.bzl",
+    "cc_grpc_library",
+    "cc_proto_library")
+
+cc_proto_library(
+    name = "admin_cc_proto",
+    deps = [":admin_proto"],
+)
+
+cc_grpc_library(
+    name = "admin_cc_grpc",
+    srcs = [":admin_proto"],
+    grpc_only = True,
+    deps = [":admin_cc_proto"],
+)

google/bigtable/v2/BUILD.bazel

@@ -361,4 +361,19 @@ csharp_gapic_assembly_pkg(
 ##############################################################################
 # C++
 ##############################################################################
-# Put your C++ rules here
+load(
+    "@com_google_googleapis_imports//:imports.bzl",
+    "cc_grpc_library",
+    "cc_proto_library")
+
+cc_proto_library(
+    name = "bigtable_cc_proto",
+    deps = [":bigtable_proto"],
+)
+
+cc_grpc_library(
+    name = "bigtable_cc_grpc",
+    srcs = [":bigtable_proto"],
+    grpc_only = True,
+    deps = [":bigtable_cc_proto"],
+)