Enable hide animation for login screen.

chrome/browser/chromeos/login/login_display_host.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_LOGIN_DISPLAY_HOST_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_LOGIN_DISPLAY_HOST_H_
 #pragma once
 
 #include <string>
 
@@ skipping 55 matching lines @@
   // Takes ownership of |screen_parameters|, which can also be NULL.
   virtual void StartWizard(
       const std::string& first_screen_name,
       DictionaryValue* screen_parameters) = 0;
 
   // Starts sign in screen.
   virtual void StartSignInScreen() = 0;
 
   // Resumes a previously started sign in screen.
   virtual void ResumeSignInScreen() = 0;
-
-  // Closes the login window.
-  virtual void CloseWindow() = 0;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_LOGIN_DISPLAY_HOST_H_