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

chrome/browser/chromeos/login/oobe_display.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_OOBE_DISPLAY_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_OOBE_DISPLAY_H_
 #pragma once
 
 #include <string>
 #include <base/basictypes.h>
 
 namespace chromeos {
 
 class EnterpriseEnrollmentScreenActor;
 class EulaScreenActor;
 class NetworkScreenActor;
-class ScreenObserver;
 class UpdateScreenActor;
 class UserImageScreenActor;
 // TODO(altimofeev): use real actors instead
 class ViewScreenDelegate;
 class WizardScreen;
 
 // Interface which is used by WizardController to do actual OOBE screens
 // showing. Also it provides actors for the OOBE screens.
 class OobeDisplay {
  public:
@@ skipping 14 matching lines @@
       GetEnterpriseEnrollmentScreenActor() = 0;
   virtual UserImageScreenActor* GetUserImageScreenActor() = 0;
   // TODO(altimofeev): use real actors instead.
   virtual ViewScreenDelegate* GetRegistrationScreenActor() = 0;
   virtual ViewScreenDelegate* GetHTMLPageScreenActor() = 0;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_OOBE_DISPLAY_H_