From 5f9d79c73aba2728202d737c607c1feb3b74b56e Mon Sep 17 00:00:00 2001
From: Esun Kim <veblush@google.com>
Date: Wed, 25 Nov 2020 18:40:13 -0800
Subject: [PATCH 1/2] Enable google-build-using-namespace

---
 .clang-tidy | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.clang-tidy b/.clang-tidy
index a9aaec4b5ab..7e38d4822e5 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -10,7 +10,6 @@ Checks: '-*,
   -performance-unnecessary-copy-initialization,
   -performance-unnecessary-value-param,
   google-*,
-  -google-build-using-namespace,
   -google-explicit-constructor,
   -google-readability-casting,
   -google-runtime-int,

From 3aba567746bd76658cca767c8a227fb6d42fa654 Mon Sep 17 00:00:00 2001
From: Esun Kim <veblush@google.com>
Date: Wed, 25 Nov 2020 19:48:21 -0800
Subject: [PATCH 2/2] Fix google-build-using-namespace

---
 .../ext/filters/client_channel/http_connect_handshaker.cc  | 7 +++----
 src/core/lib/channel/handshaker.cc                         | 4 ++--
 test/core/handshake/readahead_handshaker_server_ssl.cc     | 7 +++----
 3 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/core/ext/filters/client_channel/http_connect_handshaker.cc b/src/core/ext/filters/client_channel/http_connect_handshaker.cc
index 1b9817cee78..979248e279f 100644
--- a/src/core/ext/filters/client_channel/http_connect_handshaker.cc
+++ b/src/core/ext/filters/client_channel/http_connect_handshaker.cc
@@ -382,8 +382,7 @@ class HttpConnectHandshakerFactory : public HandshakerFactory {
 }  // namespace grpc_core
 
 void grpc_http_connect_register_handshaker_factory() {
-  using namespace grpc_core;
-  HandshakerRegistry::RegisterHandshakerFactory(
-      true /* at_start */, HANDSHAKER_CLIENT,
-      absl::make_unique<HttpConnectHandshakerFactory>());
+  grpc_core::HandshakerRegistry::RegisterHandshakerFactory(
+      true /* at_start */, grpc_core::HANDSHAKER_CLIENT,
+      absl::make_unique<grpc_core::HttpConnectHandshakerFactory>());
 }
diff --git a/src/core/lib/channel/handshaker.cc b/src/core/lib/channel/handshaker.cc
index 461a21db32f..8d1d45e5623 100644
--- a/src/core/lib/channel/handshaker.cc
+++ b/src/core/lib/channel/handshaker.cc
@@ -256,7 +256,7 @@ void HandshakeManager::DoHandshake(grpc_endpoint* endpoint,
 void grpc_handshake_manager_add(grpc_handshake_manager* mgr,
                                 grpc_handshaker* handshaker) {
   // This is a transition method to aid the API change for handshakers.
-  using namespace grpc_core;
-  RefCountedPtr<Handshaker> refd_hs(static_cast<Handshaker*>(handshaker));
+  grpc_core::RefCountedPtr<grpc_core::Handshaker> refd_hs(
+      static_cast<grpc_core::Handshaker*>(handshaker));
   mgr->Add(refd_hs);
 }
diff --git a/test/core/handshake/readahead_handshaker_server_ssl.cc b/test/core/handshake/readahead_handshaker_server_ssl.cc
index c1468503e7b..708b316e793 100644
--- a/test/core/handshake/readahead_handshaker_server_ssl.cc
+++ b/test/core/handshake/readahead_handshaker_server_ssl.cc
@@ -77,11 +77,10 @@ class ReadAheadHandshakerFactory : public HandshakerFactory {
 }  // namespace grpc_core
 
 int main(int /*argc*/, char* /*argv*/[]) {
-  using namespace grpc_core;
   grpc_init();
-  HandshakerRegistry::RegisterHandshakerFactory(
-      true /* at_start */, HANDSHAKER_SERVER,
-      absl::make_unique<ReadAheadHandshakerFactory>());
+  grpc_core::HandshakerRegistry::RegisterHandshakerFactory(
+      true /* at_start */, grpc_core::HANDSHAKER_SERVER,
+      absl::make_unique<grpc_core::ReadAheadHandshakerFactory>());
   const char* full_alpn_list[] = {"grpc-exp", "h2"};
   GPR_ASSERT(server_ssl_test(full_alpn_list, 2, "grpc-exp"));
   grpc_shutdown();