Feed the render data to MediaStreamAudioProcessor and used AudioBus in render callback.

This CL is mainly to feed the render data to MediaStreamAudioProcessor. But since it is better to have all the data format as media::AudioBus in chrome, so I changed the WebRtcAudioRendererSource::RenderData(int16*) to 
WebRtcAudioRendererSource::RenderData(media::AudioBus*), and also make MediaStreamAudioProcessor use WebRtcAudioRendererSource interface to get the render data.


BUG=264611
TEST=content_unittests and AEC works when chrome ----enable-audio-track-processing

Review URL: https://codereview.chromium.org/139303016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252554 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252554
[SyncFS] Replace TrackerSet with TrackerIDSet

Introduce TrackerIDSet and replace TrackerSet with it.
Unlike TrackerSet, TrackerIDSet doesn't have raw pointer to FileTrackers.
The replacement hides FileTrackers from the user of the class.

Review URL: https://codereview.chromium.org/171773010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252555 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252555