Add support for unmixed audio from remote WebRTC remote tracks.

content/renderer/media/media_stream_renderer_factory_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/media_stream_renderer_factory_impl.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "content/renderer/media/media_stream.h"
 #include "content/renderer/media/media_stream_video_renderer_sink.h"
 #include "content/renderer/media/media_stream_video_track.h"
@@ skipping 123 matching lines @@
   DVLOG(1) << "MediaStreamRendererFactoryImpl::GetAudioRenderer stream:"
            << base::UTF16ToUTF8(base::StringPiece16(web_stream.id()));
 
   // TODO(tommi): We need to fix the data flow so that
   // it works the same way for all track implementations, local, remote or what
   // have you.
   // In this function, we should simply create a renderer object that receives
   // and mixes audio from all the tracks that belong to the media stream.
   // For now, we have separate renderers depending on if the first audio track
   // in the stream is local or remote.
-  MediaStreamTrack* audio_track = MediaStreamTrack::GetTrack(audio_tracks[0]);
+  MediaStreamAudioTrack* audio_track = MediaStreamAudioTrack::GetTrack(
+      audio_tracks[0]);
   if (!audio_track) {
     // This can happen if the track was cloned.
     // TODO(tommi, perkj): Fix cloning of tracks to handle extra data too.
     LOG(ERROR) << "No native track for WebMediaStreamTrack.";
     return nullptr;
   }
 
   if (audio_track->is_local_track()) {
     // TODO(xians): Add support for the case where the media stream contains
     // multiple audio tracks.
@@ skipping 13 matching lines @@
 
     if (renderer.get() && !audio_device->SetAudioRenderer(renderer.get()))
       renderer = NULL;
   }
 
   return renderer.get() ? renderer->CreateSharedAudioRendererProxy(web_stream)
                         : NULL;
 }
 
 }  // namespace content