Clean up the media stream audio track code

content/renderer/media/webaudio_capturer_source.h

Index: content/renderer/media/webaudio_capturer_source.h
diff --git a/content/renderer/media/webaudio_capturer_source.h b/content/renderer/media/webaudio_capturer_source.h
index 6382bd31830768f68e8dde5bd563e32487d9f815..112ffaf0e032db16404c4733ada4174c0920126b 100644
--- a/content/renderer/media/webaudio_capturer_source.h
+++ b/content/renderer/media/webaudio_capturer_source.h
@@ -16,7 +16,6 @@
 
 namespace content {
 
-class WebRtcAudioCapturer;
 class WebRtcLocalAudioTrack;
 
 // WebAudioCapturerSource is the missing link between
@@ -44,7 +43,7 @@ class WebAudioCapturerSource
   // |track| is the sink of the data flow. |source_provider| is the source of
   // the data flow where stream information like delay, volume, key_pressed,
   // is stored.
-  void Start(WebRtcLocalAudioTrack* track, WebRtcAudioCapturer* capturer);
+  void Start(WebRtcLocalAudioTrack* track);
 
   // Called when the media audio track is stopping.
   void Stop();
@@ -62,11 +61,6 @@ class WebAudioCapturerSource
   // To avoid circular reference, a raw pointer is kept here.
   WebRtcLocalAudioTrack* track_;
 
-  // A raw pointer to the capturer to get audio processing params like
-  // delay, volume, key_pressed information.
-  // This |capturer_| is guaranteed to outlive this object.
-  WebRtcAudioCapturer* capturer_;
-
   media::AudioParameters params_;
 
   // Flag to help notify the |track_| when the audio format has changed.