GitLab

This is part 4/4 CLs to move the <audio>/<video> elements off of
a synchronous API that can lead to renderer hangs and premature
audio renderer errors.

This changes the AudioRendererMixerPool API to require an
AudioRendererSink and OutputDeviceInfo when providing a mixer.
AudioRendererMixerInputs are subsequently changed to use the new
API.

Likewise AudioRendererImpl also now uses the asynchronous API. To
simplify the async process, AudioRendererMixerInputs will only setup
correctly when OutputDeviceInfo has been requested ahead of time,
since that's the pattern that AudioRendererImpl will use.

This also moves the NullAudioSink setup from WebAudioSourceProvider
over to the AudioRendererImpl. This causes WebAudio to be disconnected
from the element, but if audio isn't work anyways, it shouldn't matter.

BUG=905506
TEST=updated tests, compiles, runs.
R=olka

Change-Id: I4edf89bb1e20cc91191a6eb97a0e38b6aeba68f8
Reviewed-on: https://chromium-review.googlesource.com/c/1347795
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612526}