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

media/audio/audio_output_controller.h

Index: media/audio/audio_output_controller.h
diff --git a/media/audio/audio_output_controller.h b/media/audio/audio_output_controller.h
index 762a9483d0fb51d1bdeed0cfa08a042508bab368..5ff8a2b236e8e435a6b0fbd7d40cda28e7896a2f 100644
--- a/media/audio/audio_output_controller.h
+++ b/media/audio/audio_output_controller.h
@@ -9,6 +9,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
+#include "base/threading/thread_checker.h"
 #include "media/audio/audio_buffers_state.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager.h"
@@ -154,6 +155,19 @@ class MEDIA_EXPORT AudioOutputController
   // 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 begins providing audio data to
+  // another destination.  |to_stream| remains under complete control of
+  // AudioOutputController.
+  void StartDiverting(AudioOutputStream* to_stream);
+
+  // Restores normal audio output behavior.  The stream that was provided in the
+  // previous call to StartDiverting() is closed at some point by
+  // AudioOutputController.
+  void StopDiverting();
+
  protected:
     // Internal state of the source.
   enum State {
@@ -196,12 +210,22 @@ class MEDIA_EXPORT AudioOutputController
   // Signals event when done if it is not NULL.
   void DoStopCloseAndClearStream(base::WaitableEvent *done);
 
-  AudioManager* audio_manager_;
+  AudioManager* const audio_manager_;
+  const AudioParameters params_;
 
   // |handler_| may be called only if |state_| is not kClosed.
   EventHandler* handler_;
+
+  // Currently open stream.
   AudioOutputStream* stream_;
 
+  // When non-NULL, audio is being diverted to this stream.
+  AudioOutputStream* diverting_to_stream_;
+
+  // Checks that the same single outside thread is calling StartDiverting() and
+  // StopDiverting().
+  base::ThreadChecker divert_thread_checker_;
+
   // The current volume of the audio stream.
   double volume_;
 
@@ -224,8 +248,6 @@ class MEDIA_EXPORT AudioOutputController
   // Number of times left.
   int number_polling_attempts_left_;
 
-  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.