Remove the AudioManager singleton.

media/audio/audio_output_dispatcher.h

Index: media/audio/audio_output_dispatcher.h
===================================================================
--- media/audio/audio_output_dispatcher.h	(revision 113173)
+++ media/audio/audio_output_dispatcher.h	(working copy)
@@ -26,6 +26,7 @@
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/timer.h"
 #include "media/audio/audio_manager.h"
 #include "media/audio/audio_parameters.h"
@@ -64,6 +65,9 @@
   // Called by AudioOutputProxy when the stream is closed.
   void StreamClosed();
 
+  // Called on the audio thread when the AudioManager is shutting down.
+  void Shutdown();
+
   MessageLoop* message_loop();
 
  private:
@@ -91,8 +95,11 @@
 
   int64 pause_delay_milliseconds_;
   size_t paused_proxies_;
-  std::vector<AudioOutputStream*> idle_streams_;
-  std::list<AudioOutputStream*> pausing_streams_;
+  typedef std::list<AudioOutputStream*> AudioOutputStreamList;
+  AudioOutputStreamList idle_streams_;
+  AudioOutputStreamList pausing_streams_;
+  // Used to post delayed tasks to ourselves that we can cancel.
+  base::WeakPtrFactory<AudioOutputDispatcher> weak_this_;
   base::DelayTimer<AudioOutputDispatcher> close_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcher);