Roll up of playback rate efficiency improvements for M56.

media/renderers/audio_renderer_impl.h

Index: media/renderers/audio_renderer_impl.h
diff --git a/media/renderers/audio_renderer_impl.h b/media/renderers/audio_renderer_impl.h
index b1622cc380deab5be5635f24ece49ef95c1258d3..d8763370664056b0a4c15484222addfa385f51e2 100644
--- a/media/renderers/audio_renderer_impl.h
+++ b/media/renderers/audio_renderer_impl.h
@@ -196,6 +196,10 @@ class MEDIA_EXPORT AudioRendererImpl
   // Updates |buffering_state_| and fires |buffering_state_cb_|.
   void SetBufferingState_Locked(BufferingState buffering_state);
 
+  // Configure's the channel mask for |algorithm_|. Must be called if the layout
+  // changes. Expect the layout in |last_decoded_channel_layout_|.
+  void ConfigureChannelMask();
+
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   std::unique_ptr<AudioBufferConverter> buffer_converter_;
@@ -234,6 +238,10 @@ class MEDIA_EXPORT AudioRendererImpl
   // sample rate changes due to implicit AAC configuration change.
   int last_decoded_sample_rate_;
 
+  // Similar to |last_decoded_sample_rate_|, used to configure the channel mask
+  // given to the |algorithm_| for efficient playback rate changes.
+  ChannelLayout last_decoded_channel_layout_;
+
   // After Initialize() has completed, all variables below must be accessed
   // under |lock_|. ------------------------------------------------------------
   base::Lock lock_;