Merge pull request #11927 from y-zeng/nameser

BUILD

build.yaml

gRPC-Core.podspec

grpc.gemspec

package.xml

...rs/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.c

src/core/lib/iomgr/nameser.h

src/core/lib/iomgr/port.h

tools/doxygen/Doxyfile.core.internal

tools/run_tests/generated/sources_and_headers.json

vsprojects/vcxproj/grpc/grpc.vcxproj

vsprojects/vcxproj/grpc/grpc.vcxproj.filters

vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj

...cts/vcxproj/grpc_test_util/grpc_test_util.vcxproj.filters

vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj

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