Crash fix: RenderProcessHostImpl media stream counts.

Multiple fixes around RenderFrameHostImpl not always notifying its
RenderProcessHostImpl that audio streams have been added/removed.
Before these fixes, RenderProcessHostImpl was sometimes leaving a
render process backgrounded indefinitely, or sometimes leaving it
non-backgrounded indefinitely.

Bug: 887208
Change-Id: I1713887c96382b8bdf032c82bb49723fc0219f71
Reviewed-on: https://chromium-review.googlesource.com/1232475
Commit-Queue: Yuri Wiitala <miu@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593354}
2 files changed