Cleanup: Remove unneeded forward declarations from chrome/browser/chromeos.

chrome/browser/chromeos/audio_handler.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 CHROME_BROWSER_CHROMEOS_AUDIO_HANDLER_H_
 #define CHROME_BROWSER_CHROMEOS_AUDIO_HANDLER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread.h"
 
-class InProcessBrowserTest;
 template <typename T> struct DefaultSingletonTraits;
 
 namespace chromeos {
 
 class AudioMixer;
 
 class AudioHandler {
  public:
   static void Initialize();
   static void Shutdown();
@@ skipping 37 matching lines @@
   scoped_ptr<AudioMixer> mixer_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioHandler);
 };
 
 }  // namespace chromeos
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(chromeos::AudioHandler);
 
 #endif  // CHROME_BROWSER_CHROMEOS_AUDIO_HANDLER_H_