Fix crash on Enrollment screen.

chrome/browser/chromeos/login/wizard_controller.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_WIZARD_CONTROLLER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_WIZARD_CONTROLLER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 115 matching lines @@
   void EnableUserImageScreenReturnToPreviousHack();
 
   // Returns a pointer to the current screen or NULL if there's no such
   // screen.
   BaseScreen* current_screen() const { return current_screen_; }
 
   // Returns true if the current wizard instance has reached the login screen.
   bool login_screen_started() const { return login_screen_started_; }
 
   // ScreenManager implementation.
+  BaseScreen* GetScreen(const std::string& screen_name) override;
   BaseScreen* CreateScreen(const std::string& screen_name) override;
 
   static const char kNetworkScreenName[];
   static const char kLoginScreenName[];
   static const char kUpdateScreenName[];
   static const char kUserImageScreenName[];
   static const char kOutOfBoxScreenName[];
   static const char kTestNoScreenName[];
   static const char kEulaScreenName[];
   static const char kEnableDebuggingScreenName[];
@@ skipping 281 matching lines @@
   BaseScreen* hid_screen_;
 
   base::WeakPtrFactory<WizardController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WizardController);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_WIZARD_CONTROLLER_H_