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

chrome/browser/chromeos/login/update_screen_actor.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_LOGIN_UPDATE_SCREEN_ACTOR_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_UPDATE_SCREEN_ACTOR_H_
 #pragma once
 
 namespace chromeos {
 
-class WizardScreen;
-class ScreenObserver;
-
 class UpdateScreenActor {
  public:
   class Delegate {
    public:
     virtual ~Delegate() {}
     // Force cancel update.
     virtual void CancelUpdate() = 0;
     virtual void OnActorDestroyed(UpdateScreenActor* actor) = 0;
   };
 
@@ skipping 19 matching lines @@
   // Shows screen curtains.
   virtual void ShowCurtain(bool enable) = 0;
 
   // Shows label for "Preparing updates" state.
   virtual void ShowPreparingUpdatesInfo(bool visible) = 0;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_UPDATE_SCREEN_ACTOR_H_