https://codereview.chromium.org/2533443002/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a8d73a9f728dd8d305feadb1a1febc75c40e13b3

commit a8d73a9f728dd8d305feadb1a1febc75c40e13b3
Author: olka <olka@chromium.org>
Date: Tue Dec 13 12:03:39 2016

Fallback to null sink moved from WebMediaPlayer to WebAudioSourceProvider::Initialize(), so that we do it on media thread. UMA stats for AudioOutputDevice status and for fallbacks to null sink.

BUG= 668506 , 668201 ,663546, 626862 , 673291 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
TBR=dalecurtis@chromium.org,dcheng@chromium.org,holte@chromium.org
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2533443002
Cr-Commit-Position: refs/heads/master@{#436614}
(cherry picked from commit e4ba2ed8354d01411848143efbe8d17b41e1853b)

Review-Url: https://codereview.chromium.org/2569883003
Cr-Commit-Position: refs/branch-heads/2924@{#472}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}

[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/content/common/media/audio_messages.h
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/content/renderer/media/html_audio_element_capturer_source_unittest.cc
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/media/audio/audio_output_device.cc
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/media/audio/null_audio_sink.cc
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/media/base/output_device_info.h
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/media/blink/webaudiosourceprovider_impl.cc
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/media/blink/webaudiosourceprovider_impl.h
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/media/blink/webaudiosourceprovider_impl_unittest.cc
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/media/blink/webmediaplayer_impl.cc
[modify] https://crrev.com/a8d73a9f728dd8d305feadb1a1febc75c40e13b3/tools/metrics/histograms/histograms.xml