Merge pull request #4360 from ctiller/who-needs-a-noop-anyway

BUILD

Makefile

binding.gyp

build.yaml

gRPC.podspec

src/core/census/grpc_filter.c

src/core/channel/noop_filter.c

src/core/channel/noop_filter.h

tools/doxygen/Doxyfile.core.internal

tools/run_tests/sources_and_headers.json

vsprojects/vcxproj/grpc/grpc.vcxproj

vsprojects/vcxproj/grpc/grpc.vcxproj.filters

vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj

...jects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters