cros: Remove unused method

chrome/browser/chromeos/login/supervised/supervised_user_creation_screen.h

 // Copyright 2014 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_SUPERVISED_SUPERVISED_USER_CREATION_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SUPERVISED_SUPERVISED_USER_CREATION_SCREEN_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 57 matching lines @@
   // CameraPresenceNotifier::Observer implementation:
   void OnCameraPresenceCheckDone(bool is_camera_present) override;
 
   // SupervisedUserSyncServiceObserver implementation
   void OnSupervisedUserAcknowledged(
       const std::string& supervised_user_id) override {}
   void OnSupervisedUsersSyncingStopped() override {}
   void OnSupervisedUsersChanged() override;
 
   // BaseScreen implementation:
-  void PrepareToShow() override;
   void Show() override;
   void Hide() override;
   std::string GetName() const override;
 
   // SupervisedUserCreationScreenHandler::Delegate implementation:
   void OnActorDestroyed(SupervisedUserCreationScreenHandler* actor) override;
   void CreateSupervisedUser(
       const base::string16& display_name,
       const std::string& supervised_user_password) override;
   void ImportSupervisedUser(const std::string& user_id) override;
@@ skipping 55 matching lines @@
 
   base::WeakPtrFactory<SupervisedUserCreationScreen> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SupervisedUserCreationScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SUPERVISED_SUPERVISED_USER_CREATION_SCREEN_H_