Merge branch 'buffer_pools_for_realsies' into grpc_slice

BUILD

CMakeLists.txt

Makefile

binding.gyp

build.yaml

config.m4

doc/images/stress_test_framework.png

doc/stress_test_framework.md

gRPC-Core.podspec

grpc.gemspec

include/grpc++/security/credentials.h

include/grpc/impl/codegen/grpc_types.h

include/grpc/impl/codegen/port_platform.h

package.xml

setup.py

src/boringssl/gen_build_yaml.py

src/core/ext/client_channel/README.md

src/core/ext/client_channel/client_channel.c

src/core/ext/client_channel/client_channel_factory.c

src/core/ext/client_channel/client_channel_factory.h