[cros,de-hack] Get rid of singleton for the WebUILoginScreen.

chrome/browser/chromeos/login/login_display.h

 // Copyright (c) 2011 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_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_LOGIN_DISPLAY_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 51 matching lines @@
     virtual void OnStartEnterpriseEnrollment() = 0;
 
    protected:
     virtual ~Delegate();
   };
 
   // |background_bounds| determines the bounds of login UI background.
   LoginDisplay(Delegate* delegate, const gfx::Rect& background_bounds);
   virtual ~LoginDisplay();
 
-  // Call for destroying a pointer of type LoginDisplay, since some subclasses
-  // are Singletons
-  virtual void Destroy();
-
   // Initializes login UI with the user pods based on list of known users and
   // guest, new user pods if those are enabled.
   virtual void Init(const std::vector<UserManager::User>& users,
                     bool show_guest,
                     bool show_new_user) = 0;
 
 
   // Called when user image has been changed.
   // |user| contains updated user.
   virtual void OnUserImageChanged(UserManager::User* user) = 0;
@@ skipping 41 matching lines @@
 
   // Bounds of the login UI background.
   gfx::Rect background_bounds_;
 
   DISALLOW_COPY_AND_ASSIGN(LoginDisplay);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_LOGIN_DISPLAY_H_