cros: Remove unused method

chrome/browser/chromeos/login/screens/device_disabled_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_SCREENS_DEVICE_DISABLED_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_DEVICE_DISABLED_SCREEN_H_
 
 #include "base/macros.h"
 #include "chrome/browser/chromeos/login/screens/base_screen.h"
 #include "chrome/browser/chromeos/login/screens/device_disabled_screen_actor.h"
@@ skipping 10 matching lines @@
 // Screen informing the user that the device has been disabled by its owner.
 class DeviceDisabledScreen : public BaseScreen,
                              public DeviceDisabledScreenActor::Delegate,
                              public system::DeviceDisablingManager::Observer {
  public:
   DeviceDisabledScreen(BaseScreenDelegate* base_screen_delegate,
                        DeviceDisabledScreenActor* actor);
   ~DeviceDisabledScreen() override;
 
   // BaseScreen:
-  void PrepareToShow() override;
   void Show() override;
   void Hide() override;
   std::string GetName() const override;
 
   // DeviceDisabledScreenActor::Delegate:
   void OnActorDestroyed(DeviceDisabledScreenActor* actor) override;
   const std::string& GetEnrollmentDomain() const override;
   const std::string& GetMessage() const override;
 
   // system::DeviceDisablingManager::Observer:
   void OnDisabledMessageChanged(const std::string& disabled_message) override;
 
  private:
   DeviceDisabledScreenActor* actor_;
   system::DeviceDisablingManager* device_disabling_manager_;
 
   // Whether the screen is currently showing.
   bool showing_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceDisabledScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_DEVICE_DISABLED_SCREEN_H_