Collapse AudioRendererMixer and OnMoreDataResampler into AudioTransform.

media/base/audio_pull_fifo.h

Index: media/base/audio_pull_fifo.h
diff --git a/media/base/audio_pull_fifo.h b/media/base/audio_pull_fifo.h
index 9fd3a8e1740c461864cf41dfc6bc0ce83ecc3816..caf73e4caccb07f8a4a532566969760d1a447a28 100644
--- a/media/base/audio_pull_fifo.h
+++ b/media/base/audio_pull_fifo.h
@@ -20,8 +20,9 @@ class MEDIA_EXPORT AudioPullFifo {
  public:
   // Callback type for providing more data into the FIFO.  Expects AudioBus
   // to be completely filled with data upon return; zero padded if not enough
-  // frames are available to satisfy the request.
-  typedef base::Callback<void(AudioBus* audio_bus)> ReadCB;
+  // frames are available to satisfy the request.  |frame_delay| is the number
+  // of output frames already processed and can be used to estimate delay.
+  typedef base::Callback<void(int frame_delay, AudioBus* audio_bus)> ReadCB;
 
   // Constructs an AudioPullFifo with the specified |read_cb|, which is used to
   // read audio data to the FIFO if data is not already available. The internal