Merge github.com:grpc/grpc into deadline_mu

BUILD

CMakeLists.txt

Makefile

WORKSPACE

build.yaml

...e/grpc++/ext/health_check_service_server_builder_option.h

include/grpc++/health_check_service_interface.h

include/grpc++/impl/codegen/call.h

include/grpc++/impl/codegen/sync_stream.h

include/grpc++/server.h

include/grpc/impl/codegen/atm_gcc_atomic.h

src/core/ext/transport/chttp2/server/chttp2_server.c

src/core/lib/channel/handshaker.c

src/core/lib/channel/handshaker.h

src/core/lib/support/sync_posix.c

src/cpp/server/health/default_health_check_service.cc

src/cpp/server/health/default_health_check_service.h

src/cpp/server/health/health.pb.c

src/cpp/server/health/health.pb.h

src/cpp/server/health/health_check_service.cc