chrome: Cleanup class/struct forward declarations

chrome/browser/ui/webui/chromeos/login/arc_terms_of_service_screen_handler.h

 // Copyright 2016 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_UI_WEBUI_CHROMEOS_LOGIN_ARC_TERMS_OF_SERVICE_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_ARC_TERMS_OF_SERVICE_SCREEN_HANDLER_H_
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "chrome/browser/chromeos/arc/optin/arc_optin_preference_handler_observer.h"
 #include "chrome/browser/chromeos/login/screens/arc_terms_of_service_screen_actor.h"
 #include "chrome/browser/ui/webui/chromeos/login/base_screen_handler.h"
 #include "chromeos/settings/timezone_settings.h"
 
 namespace arc {
 class ArcOptInPreferenceHandler;
 }
 
 namespace chromeos {
 
-class CoreOobeActor;
-
 // The sole implementation of the ArcTermsOfServiceScreenActor, using WebUI.
 class ArcTermsOfServiceScreenHandler :
     public BaseScreenHandler,
     public ArcTermsOfServiceScreenActor,
     public arc::ArcOptInPreferenceHandlerObserver,
     public system::TimezoneSettings::Observer {
  public:
   ArcTermsOfServiceScreenHandler();
   ~ArcTermsOfServiceScreenHandler() override;
 
@@ skipping 36 matching lines @@
   std::string last_applied_contry_code_;
 
   std::unique_ptr<arc::ArcOptInPreferenceHandler> pref_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcTermsOfServiceScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_ARC_TERMS_OF_SERVICE_SCREEN_HANDLER_H_