Implements AudioMessageFilter as member in RenderThread

content/renderer/media/audio_renderer_impl.h

Index: content/renderer/media/audio_renderer_impl.h
===================================================================
--- content/renderer/media/audio_renderer_impl.h	(revision 90962)
+++ content/renderer/media/audio_renderer_impl.h	(working copy)
@@ -56,7 +56,7 @@
                           public MessageLoop::DestructionObserver {
  public:
   // Methods called on Render thread ------------------------------------------
-  explicit AudioRendererImpl(AudioMessageFilter* filter);
+  AudioRendererImpl();
   virtual ~AudioRendererImpl();
 
   // Methods called on IO thread ----------------------------------------------
@@ -91,9 +91,11 @@
  private:
   // For access to constructor and IO thread methods.
   friend class AudioRendererImplTest;
+  friend class DelegateCaller;
   FRIEND_TEST_ALL_PREFIXES(AudioRendererImplTest, Stop);
   FRIEND_TEST_ALL_PREFIXES(AudioRendererImplTest,
                            DestroyedMessageLoop_ConsumeAudioSamples);
+
   // Helper methods.
   // Convert number of bytes to duration of time using information about the
   // number of channels, sample rate and sample bits.
@@ -114,11 +116,11 @@
   // Called on IO thread when message loop is dying.
   virtual void WillDestroyCurrentMessageLoop();
 
+  void Send(IPC::Message* message);
+
   // Used to calculate audio delay given bytes.
   uint32 bytes_per_second_;
 
-  scoped_refptr<AudioMessageFilter> filter_;
-
   // ID of the stream created in the browser process.
   int32 stream_id_;
 
@@ -126,8 +128,8 @@
   scoped_ptr<base::SharedMemory> shared_memory_;
   uint32 shared_memory_size_;
 
-  // Message loop for the IO thread.
-  MessageLoop* io_loop_;
+  // Cached audio message filter (lives on the main render thread).
+  scoped_refptr<AudioMessageFilter> filter_;
 
   // Protects:
   // - |stopped_|