MediaStream audio object graph untangling and clean-ups.

content/renderer/media/speech_recognition_audio_sink.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/speech_recognition_audio_sink.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/logging.h"
@@ skipping 43 matching lines @@
     audio_converter_->RemoveInput(this);
 
   // Notify the track before this sink goes away.
   if (!track_stopped_)
     MediaStreamAudioSink::RemoveFromAudioTrack(this, track_);
 }
 
 // static
 bool SpeechRecognitionAudioSink::IsSupportedTrack(
     const blink::WebMediaStreamTrack& track) {
-  if (track.source().getType() != blink::WebMediaStreamSource::TypeAudio)
-    return false;
-
   MediaStreamAudioSource* native_source =
-      static_cast<MediaStreamAudioSource*>(track.source().getExtraData());
+      MediaStreamAudioSource::From(track.source());
   if (!native_source)
     return false;
 
   const StreamDeviceInfo& device_info = native_source->device_info();
   // Purposely only support tracks from an audio device. Dissallow WebAudio.
   return (device_info.device.type == content::MEDIA_DEVICE_AUDIO_CAPTURE);
 }
 
 void SpeechRecognitionAudioSink::OnSetFormat(
     const media::AudioParameters& input_params) {
@@ skipping 98 matching lines @@
 }
 
 media::AudioInputBuffer*
 SpeechRecognitionAudioSink::GetAudioInputBuffer() const {
   DCHECK(capture_thread_checker_.CalledOnValidThread());
   DCHECK(shared_memory_.memory());
   return static_cast<media::AudioInputBuffer*>(shared_memory_.memory());
 }
 
 }  // namespace content