Reland "Avoid hitting the thread check when WebRtcAudioRenderer is going away"

content/renderer/media/webrtc_audio_device_impl.cc

Index: content/renderer/media/webrtc_audio_device_impl.cc
diff --git a/content/renderer/media/webrtc_audio_device_impl.cc b/content/renderer/media/webrtc_audio_device_impl.cc
index 18aa1e985d11e3511fa2932f6113bcdc233ee3d9..48dbdc6af97b04de2b870d28de85995c84b92086 100644
--- a/content/renderer/media/webrtc_audio_device_impl.cc
+++ b/content/renderer/media/webrtc_audio_device_impl.cc
@@ -177,6 +177,12 @@ void WebRtcAudioDeviceImpl::RemoveAudioRenderer(WebRtcAudioRenderer* renderer) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK_EQ(renderer, renderer_);
   base::AutoLock auto_lock(lock_);
+  // Notify the playout sink of the change.
+  for (PlayoutDataSinkList::const_iterator it = playout_sinks_.begin();
+       it != playout_sinks_.end(); ++it) {
+    (*it)->OnPlayoutDataSourceChanged();
+  }
+
   renderer_ = NULL;
   playing_ = false;
 }