Commits http://codereview.chromium.org/7157001/.

content/renderer/media/audio_renderer_impl.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Audio rendering unit utilizing audio output stream provided by browser
 // process through IPC.
 //
 // Relationship of classes.
 //
 //    AudioRendererHost                AudioRendererImpl
@@ skipping 40 matching lines @@
 #include "media/filters/audio_renderer_base.h"
 
 class AudioMessageFilter;
 
 class AudioRendererImpl : public media::AudioRendererBase,
                           public AudioMessageFilter::Delegate,
                           public base::DelegateSimpleThread::Delegate,
                           public MessageLoop::DestructionObserver {
  public:
   // Methods called on Render thread ------------------------------------------
-  explicit AudioRendererImpl(AudioMessageFilter* filter);
+  explicit AudioRendererImpl();
   virtual ~AudioRendererImpl();
 
   // Methods called on IO thread ----------------------------------------------
   // AudioMessageFilter::Delegate methods, called by AudioMessageFilter.
   virtual void OnRequestPacket(AudioBuffersState buffers_state);
   virtual void OnStateChanged(AudioStreamState state);
   virtual void OnCreated(base::SharedMemoryHandle handle, uint32 length);
   virtual void OnLowLatencyCreated(base::SharedMemoryHandle handle,
                                    base::SyncSocket::Handle socket_handle,
                                    uint32 length);
@@ skipping 22 matching lines @@
   // We are using either low- or high-latency code path.
   enum LatencyType {
     kUninitializedLatency = 0,
     kLowLatency,
     kHighLatency
   };
   static LatencyType latency_type_;
 
   // 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.
   base::TimeDelta ConvertToDuration(int bytes);
 
   // Methods call on IO thread ------------------------------------------------
   // The following methods are tasks posted on the IO thread that needs to
@@ skipping 23 matching lines @@
   virtual void CreateAudioThread();
 
   // Accessors used by tests.
   LatencyType latency_type() {
     return latency_type_;
   }
 
   // Should be called before any class instance is created.
   static void set_latency_type(LatencyType latency_type);
 
+  // Helper method for IPC send calls.
+  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_;
 
   // Memory shared by the browser process for audio buffer.
   scoped_ptr<base::SharedMemory> shared_memory_;
   uint32 shared_memory_size_;
 
+  // Cached audio message filter (lives on the main render thread).
+  scoped_refptr<AudioMessageFilter> filter_;
+
   // Low latency IPC stuff.
   scoped_ptr<base::SyncSocket> socket_;
 
   // That thread waits for audio input.
   scoped_ptr<base::DelegateSimpleThread> audio_thread_;
 
-  // Message loop for the IO thread.
-  MessageLoop* io_loop_;
-
   // Protects:
   // - |stopped_|
   // - |pending_request_|
   // - |request_buffers_state_|
   base::Lock lock_;
 
   // A flag that indicates this filter is called to stop.
   bool stopped_;
 
   // A flag that indicates an outstanding packet request.
   bool pending_request_;
 
   // State of the audio buffers at time of the last request.
   AudioBuffersState request_buffers_state_;
 
   // State variables for prerolling.
   bool prerolling_;
 
   // Remaining bytes for prerolling to complete.
   uint32 preroll_bytes_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererImpl);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_