Fix python 2.7 & 3.4 artifacts on kokoro

Add idiomatic C++ API for grpc::Slice construction

Do not return calls on server when request proto fails to deserialize.

require using grpc_slice

Restore interop_client_main

Add GTS plugin

Fix image path when pulled from dockerhub.

Narrow src/python/.gitignore to only what it needs to ignore.

Fix fd_orphan() in ev_epollsig_linux

"proto" and "*.egg-info/" are no longer generated, "src/" can be
narrowed to "/src/", and "*_pb2.py" and "*_pb2_grpc.py" are covered by
.gitignore files in parent directories.

Added C++ to interop_matrix and created a kokoro config

Set owners for client_channel tree.

Implement stream compression lib module

Add policy to comments

Reset OWNERS state

Revert "Experiment: remove top level owners - test the model"

Experiment: remove top level owners - test the model

Experiment: remove top level owners

Destroy mutex on subchannel destruction

Fix ruby memory leaks when composing credentials, noticed with asan

Inproc Tracer

Tracer Sanity

Put thread creation and join under lock

More parallelism for multilang linux tests

In-process transport