GitLab

* Kill the Session after 10s of no activity in the audio or video
  stream.
* Kill the Session after 5s if no offer message is received.
* Fix reporting of messages from unknown namespaces in the Cast
  Streaming MessagePort.

Bug: 1087528, 1087528
Change-Id: I69b44bea3b142e7cf12c32106a279ef37710c56b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2451525Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815876}