cros: Remove unused method

chrome/browser/chromeos/login/screens/network_screen.h

 // Copyright (c) 2012 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_NETWORK_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_NETWORK_SCREEN_H_
 
 #include <memory>
 
 #include "base/compiler_specific.h"
@@ skipping 44 matching lines @@
   };
 
   NetworkScreen(BaseScreenDelegate* base_screen_delegate,
                 Delegate* delegate,
                 NetworkView* view);
   ~NetworkScreen() override;
 
   static NetworkScreen* Get(ScreenManager* manager);
 
   // NetworkModel implementation:
-  void PrepareToShow() override;
   void Show() override;
   void Hide() override;
   void Initialize(::login::ScreenContext* context) override;
   void OnViewDestroyed(NetworkView* view) override;
   void OnUserAction(const std::string& action_id) override;
   void OnContextKeyUpdated(const ::login::ScreenContext::KeyType& key) override;
   std::string GetLanguageListLocale() const override;
   const base::ListValue* GetLanguageList() const override;
   void UpdateLanguageList() override;
 
@@ skipping 124 matching lines @@
   base::ObserverList<Observer> observers_;
 
   base::WeakPtrFactory<NetworkScreen> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_NETWORK_SCREEN_H_