GitLab

Add state to support pausing a web audio device such that it can be
restarted when the frame is returned to be visible.

BUG=907125

Change-Id: I01aef9c19c81e35e68ee1e299e16cd6c9946ebde
Reviewed-on: https://chromium-review.googlesource.com/c/1344265Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Rick Byers <rbyers@chromium.org>
Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611881}