MediaStream audio object graph untangling and clean-ups.

content/renderer/media/media_stream_audio_source.cc

Index: content/renderer/media/media_stream_audio_source.cc
diff --git a/content/renderer/media/media_stream_audio_source.cc b/content/renderer/media/media_stream_audio_source.cc
index c643140e4dbdb6ef5d3d294477a3b7f3cb4cd785..d2027fd939e797db1171625fcf469f8466c2fd36 100644
--- a/content/renderer/media/media_stream_audio_source.cc
+++ b/content/renderer/media/media_stream_audio_source.cc
@@ -4,7 +4,9 @@
 
 #include "content/renderer/media/media_stream_audio_source.h"
 
+#include "content/renderer/media/webrtc_local_audio_track.h"
 #include "content/renderer/render_frame_impl.h"
+#include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 
 namespace content {
 
@@ -13,20 +15,33 @@ MediaStreamAudioSource::MediaStreamAudioSource(
     const StreamDeviceInfo& device_info,
     const SourceStoppedCallback& stop_callback,
     PeerConnectionDependencyFactory* factory)
-    : render_frame_id_(render_frame_id), factory_(factory) {
+    : render_frame_id_(render_frame_id), factory_(factory),
+      weak_factory_(this) {
   SetDeviceInfo(device_info);
   SetStopCallback(stop_callback);
 }
 
 MediaStreamAudioSource::MediaStreamAudioSource()
-    : render_frame_id_(-1), factory_(NULL) {
+    : render_frame_id_(-1), factory_(NULL), weak_factory_(this) {
 }
 
 MediaStreamAudioSource::~MediaStreamAudioSource() {}
 
+// static
+MediaStreamAudioSource* MediaStreamAudioSource::From(
+    const blink::WebMediaStreamSource& source) {
+  if (source.isNull() ||
+      source.getType() != blink::WebMediaStreamSource::TypeAudio) {
+    return nullptr;
+  }
+  return static_cast<MediaStreamAudioSource*>(source.getExtraData());
+}
+
 void MediaStreamAudioSource::DoStopSource() {
-  if (audio_capturer_.get())
+  if (audio_capturer_)
     audio_capturer_->Stop();
+  if (webaudio_capturer_)
+    webaudio_capturer_->Stop();
 }
 
 void MediaStreamAudioSource::AddTrack(
@@ -52,4 +67,20 @@ void MediaStreamAudioSource::AddTrack(
   callback.Run(this, MEDIA_DEVICE_OK, "");
 }
 
+void MediaStreamAudioSource::StopAudioDeliveryTo(MediaStreamAudioTrack* track) {
+  DCHECK(track);
+  if (audio_capturer_) {
+    // The cast here is safe because only WebRtcLocalAudioTracks are ever used
+    // with WebRtcAudioCapturer sources.
+    //
+    // TODO(miu): That said, this ugly cast won't be necessary after my
+    // soon-upcoming refactoring change.
+    audio_capturer_->RemoveTrack(static_cast<WebRtcLocalAudioTrack*>(track));
+  }
+  if (webaudio_capturer_) {
+    // A separate source is created for each track, so just stop the source.
+    webaudio_capturer_->Stop();
+  }
+}
+
 }  // namespace content