Cleaned up the WebRtcAudioCapturer a bit.

content/renderer/media/media_stream_impl.cc

Index: content/renderer/media/media_stream_impl.cc
diff --git a/content/renderer/media/media_stream_impl.cc b/content/renderer/media/media_stream_impl.cc
index f659aaf9c93188385bbe257acea278284f1033cc..d692de638de64936a9cf2608788b43950a56dd1a 100644
--- a/content/renderer/media/media_stream_impl.cc
+++ b/content/renderer/media/media_stream_impl.cc
@@ -730,6 +730,13 @@ void MediaStreamImpl::StopLocalSource(
   if (source.type() == blink::WebMediaStreamSource::TypeAudio) {
     if (extra_data->GetAudioCapturer()) {
       extra_data->GetAudioCapturer()->Stop();
+
+      // Remove the capturer object from the WebRtcAudioDeviceImpl after it
+      // stops.
+      WebRtcAudioDeviceImpl* audio_device =

[perkj_chrome, 2014/01/12 21:53:06]

Can this be moved to AudioCapturer::Stop instead? - ie - let the capturer know
what WebRtcAudioDeviceImpl it belongs to. It seems wrong that MediaStreamImpl
should have anything to do with this.  

+          dependency_factory_->GetWebRtcAudioDevice();
+      if (audio_device)
+        audio_device->RemoveAudioCapturer(extra_data->GetAudioCapturer());
     }
   }
 
@@ -802,18 +809,33 @@ bool MediaStreamImpl::GetAuthorizedDeviceInfoForAudioRenderer(
     int* output_frames_per_buffer) {
   DCHECK(CalledOnValidThread());
 
-  WebRtcAudioDeviceImpl* audio_device =
-      dependency_factory_->GetWebRtcAudioDevice();
-  if (!audio_device)
-    return false;
+  // Loop through the sources and find out the capturer that can provide
+  // the paired device information for the audio renderer.
+  scoped_refptr<WebRtcAudioCapturer> capturer;
+  for (LocalStreamSources::const_iterator it = local_sources_.begin();

[perkj_chrome, 2014/01/12 21:53:06]

This is kind of backwards. We moved this info to the audio device in order to be
able to refactor render creation to a separate file and don't depend on
MediaStreamImpl. 
So, please don't depend on anything in MediaStreamImpl. 

[no longer working on chromium, 2014/01/13 16:59:59]

Done.

+       it != local_sources_.end(); ++it) {
+    MediaStreamSourceExtraData* extra_data =
+        static_cast<MediaStreamSourceExtraData*>(it->source.extraData());
+    if (it->source.type() == blink::WebMediaStreamSource::TypeAudio &&
+        extra_data->GetAudioCapturer() &&
+        !extra_data->GetAudioCapturer()->device_id().empty()) {

[perkj_chrome, 2014/01/12 21:53:06]

GetAudioCapturer()->device_id().empty() ? 
Can this be expressed in a different way if it is needed at all? 

[no longer working on chromium, 2014/01/13 16:59:59]

Remove now.

+      // If there are more than one open capture devices, return false because
+      // we have no way to pick an appropriate device.
+      if (capturer) {
+        DLOG(WARNING) << "Failed to get the authorized paired playout device "
+                      << "since there are more than one open capture devices.";
+        return false;
+      }
+      capturer = extra_data->GetAudioCapturer();
+    }
+  }
 
-  if (!audio_device->GetDefaultCapturer())
+  if (!capturer)
     return false;
 
-  return audio_device->GetDefaultCapturer()->GetPairedOutputParameters(
-      session_id,
-      output_sample_rate,
-      output_frames_per_buffer);
+  return capturer->GetPairedOutputParameters(session_id,
+                                             output_sample_rate,
+                                             output_frames_per_buffer);
 }
 
 MediaStreamSourceExtraData::MediaStreamSourceExtraData(