Expose flash playback status and volume control to content renderer
This CL plumbs flash playback status and volume control to the
content renderer. It basically lets the renderer know when flash
starts/stops to play sound, and let it be able to control it's
volume.
The plumbing is to be continued to WebContents, and then we are
able to let flash be controlled by MediaSession, which prevents
multiple tabs from playing sound at the same time (which usually
annoys the user).
Follow-up CL:
https://codereview.chromium.org/2060933002/
BUG=619084
Review-Url: https://codereview.chromium.org/2065513004
Cr-Commit-Position: refs/heads/master@{#401687}
12 files changed
