Tab Audio Capture: Browser-side connect/disconnect functionality.

media/audio/audio_output_controller.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_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 45 matching lines @@
 // The AudioOutputStream can request data from the AudioOutputController via the
 // AudioSourceCallback interface. AudioOutputController uses the SyncReader
 // passed to it via construction to synchronously fulfill this read request.
 //
 // Since AudioOutputController uses AudioManager's message loop the controller
 // uses WeakPtr to allow safe cancellation of pending tasks.
 //
 
 namespace media {
 
+// TODO(miu): STUB
+class DivertedAudioOutputStream : public AudioOutputStream {
+};
+
 class MEDIA_EXPORT AudioOutputController
     : public base::RefCountedThreadSafe<AudioOutputController>,
       public AudioOutputStream::AudioSourceCallback,
       NON_EXPORTED_BASE(public AudioManager::AudioDeviceListener)  {
  public:
   // An event handler that receives events from the AudioOutputController. The
   // following methods are called on the audio manager thread.
   class MEDIA_EXPORT EventHandler {
    public:
     virtual void OnCreated(AudioOutputController* controller) = 0;
@@ skipping 75 matching lines @@
                            AudioBuffersState buffers_state) OVERRIDE;
   virtual void OnError(AudioOutputStream* stream, int code) OVERRIDE;
   virtual void WaitTillDataReady() OVERRIDE;
 
   // AudioDeviceListener implementation.  When called AudioOutputController will
   // shutdown the existing |stream_|, transition to the kRecreating state,
   // create a new stream, and then transition back to an equivalent state prior
   // to being called.
   virtual void OnDeviceChange() OVERRIDE;
 
+  // Creates a DivertedAudioOutputStream and diverts audio data to it, away from
+  // the existing AudioOutputStream.  The caller owns the returned object.  When
+  // the object's destructor is invoked (on the IO thread), the diversion
+  // reverts.
+  DivertedAudioOutputStream* Divert();

[Alpha Left Google, 2012/11/20 21:49:43]

I think this class should be DAOS.

[miu, 2012/11/21 08:27:48]

Yep.  The more I think about it, the more we should have a Revert() method to
un-divert the stream.  I'll make that change.

+
  protected:
     // Internal state of the source.
   enum State {
     kEmpty,
     kCreated,
     kPlaying,
     kStarting,
     kPausedWhenStarting,
     kPaused,
     kClosed,
@@ skipping 64 matching lines @@
   // shutdown and force it to wait for the most delayed task.
   // Also, if we're shutting down, we do not want to poll for more data.
   base::WeakPtrFactory<AudioOutputController> weak_this_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_