[Cast] Remove AudioDecoder's dependency on WebRTC, and refactor/clean-up AudioReceiver.

media/cast/cast_receiver_impl.cc

Index: media/cast/cast_receiver_impl.cc
diff --git a/media/cast/cast_receiver_impl.cc b/media/cast/cast_receiver_impl.cc
index cee29ecb0649e178dcd61188a855129b12d87cb8..f0152394c56ca7e4fdd82830dd4bc04264be7267 100644
--- a/media/cast/cast_receiver_impl.cc
+++ b/media/cast/cast_receiver_impl.cc
@@ -49,16 +49,12 @@ class LocalFrameReceiver : public FrameReceiver {
                                            callback));
   }
 
-  virtual void GetRawAudioFrame(int number_of_10ms_blocks,
-                                int desired_frequency,
-                                const AudioFrameDecodedCallback& callback)
+  virtual void GetRawAudioFrame(const AudioFrameDecodedCallback& callback)
       OVERRIDE {
     cast_environment_->PostTask(CastEnvironment::MAIN,
                                 FROM_HERE,
                                 base::Bind(&AudioReceiver::GetRawAudioFrame,
                                            audio_receiver_->AsWeakPtr(),
-                                           number_of_10ms_blocks,
-                                           desired_frequency,
                                            callback));
   }