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 140 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;
 
+  // Accessor to audio output parameters.
+  const AudioParameters& params() const { return params_; }
+
+  // Stops the normal audio output stream and creates an AudioSourceCallback to
+  // provide audio data to some other destination.  The given object will always
+  // return data when OnMoreData() is invoked, even if the underlying
+  // implementation is paused/stopped.  AudioOutputController retains ownership
+  // of the returned object.
+  AudioOutputStream::AudioSourceCallback* Divert();
+
+  // Restores normal audio output behavior for the current playback state.
+  // |asc| is the pointer returned by the previous call to Divert() and becomes
+  // invalid once this method is called.
+  void Revert(AudioOutputStream::AudioSourceCallback* asc);
+
  protected:
     // Internal state of the source.
   enum State {
     kEmpty,
     kCreated,
     kPlaying,
     kStarting,
     kPausedWhenStarting,
     kPaused,
     kClosed,
@@ skipping 50 matching lines @@
   // SyncReader is used only in low latency mode for synchronous reading.
   SyncReader* sync_reader_;
 
   // The message loop of audio manager thread that this object runs on.
   scoped_refptr<base::MessageLoopProxy> message_loop_;
 
   // When starting stream we wait for data to become available.
   // Number of times left.
   int number_polling_attempts_left_;
 
-  AudioParameters params_;
+  const AudioParameters params_;
 
   // Used to post delayed tasks to ourselves that we can cancel.
   // We don't want the tasks to hold onto a reference as it will slow down
   // 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_