cros: Remove unused method

chrome/browser/chromeos/login/screens/controller_pairing_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_CONTROLLER_PAIRING_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_CONTROLLER_PAIRING_SCREEN_H_
 
 #include "base/macros.h"
 
 #include "chrome/browser/chromeos/login/screens/base_screen.h"
@@ skipping 26 matching lines @@
       pairing_chromeos::ControllerPairingController* shark_controller);
   ~ControllerPairingScreen() override;
 
  private:
   typedef pairing_chromeos::ControllerPairingController::Stage Stage;
 
   void CommitContextChanges();
   bool ExpectStageIs(Stage stage) const;
 
   // Overridden from BaseScreen:
-  void PrepareToShow() override;
   void Show() override;
   void Hide() override;
   std::string GetName() const override;
 
   // Overridden from pairing_chromeos::ControllerPairingController::Observer:
   void PairingStageChanged(Stage new_stage) override;
   void DiscoveredDevicesListChanged() override;
 
   // Overridden from ControllerPairingView::Delegate:
   void OnActorDestroyed(ControllerPairingScreenActor* actor) override;
@@ skipping 13 matching lines @@
   // If this one is |false| first device in device list will be preselected on
   // next device list update.
   bool device_preselected_;
 
   DISALLOW_COPY_AND_ASSIGN(ControllerPairingScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_CONTROLLER_PAIRING_SCREEN_H_