Associate audio streams with their source/destination RenderView.

media/audio/audio_output_ipc.h

 // Copyright (c) 2012 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.
 
 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_
 
+#include "base/memory/weak_ptr.h"
 #include "base/shared_memory.h"
 #include "base/sync_socket.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // Contains IPC notifications for the state of the server side
 // (AudioOutputController) audio state changes and when an AudioOutputController
 // has been created.  Implemented by AudioOutputDevice.
@@ skipping 30 matching lines @@
   virtual void OnIPCClosed() = 0;
 
  protected:
   virtual ~AudioOutputIPCDelegate();
 };
 
 // Provides IPC functionality for an AudioOutputDevice.  The implementation
 // should asynchronously deliver the messages to an AudioOutputController object
 // (or create one in the case of CreateStream()), that may live in a separate
 // process.
-class MEDIA_EXPORT AudioOutputIPC {
+class MEDIA_EXPORT AudioOutputIPC
+    : public base::SupportsWeakPtr<AudioOutputIPC> {

[scherkus (not reviewing), 2012/11/27 22:55:26]

Ahh! What was the motivation for this change?

I don't approve of this sort of WeakPtr usage -- for details you can read
willchan@'s rant on chromium-dev:
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/Oy3uuiTSwDk/5UDyR...

[miu, 2012/11/28 07:26:20]

Reverted the changes to this file.

I had meant to come back to this.  If you're curious, the original motivation
was due to the fact that I wasn't sure whether AudioOutputIPC would outlive
AudioOutputDevice, and I needed to be sure AudioOutputIPC::RemoveDelegate()
could be safely called from the destructor.  I resolved all of this.

  public:
   // Registers an AudioOutputIPCDelegate and returns a |stream_id| that must
   // be used with all other IPC functions in this interface.
   virtual int AddDelegate(AudioOutputIPCDelegate* delegate) = 0;
 
   // Unregisters a delegate that was previously registered via a call to
   // AddDelegate().  The audio stream should be in a closed state prior to
   // calling this function.
   virtual void RemoveDelegate(int stream_id) = 0;
 
@@ skipping 28 matching lines @@
   // Sets the volume of the audio stream.
   virtual void SetVolume(int stream_id, double volume) = 0;
 
  protected:
   virtual ~AudioOutputIPC();
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_IPC_H_