Merge pull request #6016 from dgquintas/subchannel_factory_create_lb_channel

BUILD

Makefile

binding.gyp

build.yaml

config.m4

gRPC.podspec

grpc.gemspec

package.json

package.xml

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/resolver/sockaddr/sockaddr_resolver.c

src/core/ext/resolver/zookeeper/zookeeper_resolver.c

...ore/ext/transport/chttp2/client/insecure/channel_create.c

...xt/transport/chttp2/client/secure/secure_channel_create.c

src/core/lib/client_config/README.md

src/core/lib/client_config/client_channel_factory.c

src/core/lib/client_config/client_channel_factory.h

src/core/lib/client_config/lb_policy_factory.h