GitLab

ChannelMojo::OnConnect() ignores errors in Send() but the error
results deleting |message_readrer_| which causes null access.
This CL add an error check for that.

This also adds some hooks to make this testable by
faking lower level API.

TEST=ipc_channel_mojo_unittest.cc
BUG=410813
R=yzshen@chromium.org, viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/554363004

Cr-Commit-Position: refs/heads/master@{#294997}