chromeos: Cleanup class/struct fwd declarations

chromeos/dbus/fake_cras_audio_client.h

 // Copyright (c) 2013 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 CHROMEOS_DBUS_FAKE_CRAS_AUDIO_CLIENT_H_
 #define CHROMEOS_DBUS_FAKE_CRAS_AUDIO_CLIENT_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "chromeos/chromeos_export.h"
 #include "chromeos/dbus/cras_audio_client.h"
 
 namespace chromeos {
 
-class CrasAudioHandlerTest;
-
 // The CrasAudioClient implementation used on Linux desktop.
 class CHROMEOS_EXPORT FakeCrasAudioClient : public CrasAudioClient {
  public:
   FakeCrasAudioClient();
   ~FakeCrasAudioClient() override;
 
   // CrasAudioClient overrides:
   void Init(dbus::Bus* bus) override;
   void AddObserver(Observer* observer) override;
   void RemoveObserver(Observer* observer) override;
@@ skipping 56 matching lines @@
   // SetOutputNodeVolume fake dbus call.
   bool notify_volume_change_with_delay_ = false;
   base::ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeCrasAudioClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_FAKE_CRAS_AUDIO_CLIENT_H_