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

chrome/browser/ui/webui/chromeos/login/base_screen_handler.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_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_
 #pragma once
 
 #include "content/browser/webui/web_ui.h"
+#include "ui/gfx/native_widget_types.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace chromeos {
 
 // Base class for the OOBE/Login WebUI handlers.
 class BaseScreenHandler : public WebUIMessageHandler {
  public:
@@ skipping 12 matching lines @@
   // Called when the page is ready and handler can do initialization.
   virtual void Initialize() = 0;
 
   // Show selected WebUI |screen|. Optionally it can pass screen initialization
   // data via |data| parameter.
   void ShowScreen(const char* screen, const base::DictionaryValue* data);
 
   // Whether page is ready.
   bool page_is_ready() const { return page_is_ready_; }
 
+  // Returns the window which shows us.
+  gfx::NativeWindow GetNativeWindow();
+
  private:
   // Keeps whether page is ready.
   bool page_is_ready_;
 
   DISALLOW_COPY_AND_ASSIGN(BaseScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_