Share one thread between all AudioOutputControllers instead of creating one per stream.

media/audio/win/audio_manager_win.h

Index: media/audio/win/audio_manager_win.h
diff --git a/media/audio/win/audio_manager_win.h b/media/audio/win/audio_manager_win.h
index 21a40141606324f1a0664a08e1b41d6f7f5ec46a..b8bd57948c362c49bf24e710f1cd972b8b3c50b5 100644
--- a/media/audio/win/audio_manager_win.h
+++ b/media/audio/win/audio_manager_win.h
@@ -8,7 +8,7 @@
 #include <windows.h>
 
 #include "base/basictypes.h"
-#include "media/audio/audio_io.h"
+#include "media/audio/audio_manager_base.h"
 
 class PCMWaveInAudioInputStream;
 class PCMWaveOutAudioOutputStream;
@@ -16,7 +16,7 @@ class PCMWaveOutAudioOutputStream;
 // Windows implementation of the AudioManager singleton. This class is internal
 // to the audio output and only internal users can call methods not exposed by
 // the AudioManager class.
-class AudioManagerWin : public AudioManager {
+class AudioManagerWin : public AudioManagerBase {
  public:
   AudioManagerWin() {}
   // Implementation of AudioManager.