Mojo: Remove DCHECK disallowing passing of a remote message pipe.
This will make it set up a proxy message pipe, and is a stopgap measure
until we have proper message pipe passing (across multiple
channels/processes).
I don't know what bugs there might be, though I added a basic test
(across a single remote message pipe and back). I should add yet more
tests.
R=davemoore@chromium.org
Review URL: https://codereview.chromium.org/566783002
Cr-Commit-Position: refs/heads/master@{#294686}
2 files changed
