cros: Remove unused method

chrome/browser/chromeos/login/screens/wrong_hwid_screen_actor.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 CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_WRONG_HWID_SCREEN_ACTOR_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_WRONG_HWID_SCREEN_ACTOR_H_
 
 #include <string>
 
 namespace chromeos {
@@ skipping 10 matching lines @@
     // Called when screen is exited.
     virtual void OnExit() = 0;
 
     // This method is called, when actor is being destroyed. Note, if Delegate
     // is destroyed earlier then it has to call SetDelegate(NULL).
     virtual void OnActorDestroyed(WrongHWIDScreenActor* actor) = 0;
   };
 
   virtual ~WrongHWIDScreenActor() {}
 
-  virtual void PrepareToShow() = 0;
   virtual void Show() = 0;
   virtual void Hide() = 0;
   virtual void SetDelegate(Delegate* delegate) = 0;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_WRONG_HWID_SCREEN_ACTOR_H_