Merge pull request #6875 from y-zeng/log_check

include/grpc/impl/codegen/log.h

include/grpc/impl/codegen/port_platform.h

include/grpc/support/string_util.h

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

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

...core/ext/transport/chttp2/server/insecure/server_chttp2.c

...ext/transport/chttp2/server/secure/server_secure_chttp2.c

src/core/ext/transport/chttp2/transport/chttp2_transport.c

src/core/ext/transport/chttp2/transport/parsing.c

src/core/lib/channel/compress_filter.c

src/core/lib/iomgr/iomgr.c

src/core/lib/support/log_linux.c

src/core/lib/support/string.c

src/core/lib/support/string.h

src/core/lib/surface/call.c

src/core/lib/surface/call_log_batch.c

src/core/lib/transport/metadata.c

src/python/grpcio/grpc/_cython/imports.generated.h

src/ruby/ext/grpc/rb_grpc_imports.generated.h

test/core/client_config/lb_policies_test.c