Merge branch 'master' into fd_rw_atm_closure

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

include/grpc/support/useful.h

src/core/ext/client_channel/client_channel.c

src/core/ext/client_channel/lb_policy.c

src/core/ext/client_channel/subchannel.c

src/core/ext/lb_policy/grpclb/grpclb.c

src/core/ext/lb_policy/pick_first/pick_first.c

src/core/ext/lb_policy/round_robin/round_robin.c

src/core/ext/resolver/dns/native/dns_resolver.c

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