reintroduce anon namespace

test/cpp/util/channel_trace_proto_helper.cc

@@ -30,6 +30,8 @@
 
 namespace grpc {
   
+namespace {
+
 // Generic helper that takes in a json string, converts it to a proto, and
 // then back to json. This ensures that the json string was correctly formatted
 // according to https://developers.google.com/protocol-buffers/docs/proto3#json
@@ -46,6 +48,8 @@ void VaidateProtoJsonTranslation(char* json_c_str) {
   EXPECT_EQ(json_str, proto_json_str);
 }
 
+} // namespace
+
 namespace testing {
 
 void ValidateChannelTraceProtoJsonTranslation(char* json_c_str) {