Cleanup: Another round of unused forward declaration cleanup.

media/audio/win/audio_manager_win.h

 // Copyright (c) 2011 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_WIN_AUDIO_MANAGER_WIN_H_
 #define MEDIA_AUDIO_WIN_AUDIO_MANAGER_WIN_H_
 
 #include <windows.h>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "media/audio/audio_manager_base.h"
 
-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 MEDIA_EXPORT AudioManagerWin : public AudioManagerBase {
  public:
   AudioManagerWin();
   // Implementation of AudioManager.
   virtual bool HasAudioOutputDevices() OVERRIDE;
   virtual bool HasAudioInputDevices() OVERRIDE;
   virtual AudioOutputStream* MakeAudioOutputStream(
@@ skipping 34 matching lines @@
     enumeration_type_ = type;
   }
 
   // Number of currently open output streams.
   int num_output_streams_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerWin);
 };
 
 #endif  // MEDIA_AUDIO_WIN_AUDIO_MANAGER_WIN_H_