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

chrome/browser/ui/webui/chromeos/login/oobe_ui.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_OOBE_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_OOBE_UI_H_
 #pragma once
 
 #include "chrome/browser/chromeos/login/oobe_display.h"
 #include "chrome/browser/ui/webui/chrome_web_ui.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace chromeos {
 class BaseScreenHandler;
 class CoreOobeHandler;
 class SigninScreenHandler;
+class SigninScreenHandlerDelegate;
 }
 
 namespace chromeos {
 
 // A custom WebUI that defines datasource for out-of-box-experience (OOBE) UI:
 // - welcome screen (setup language/keyboard/network).
 // - eula screen (CrOS (+ OEM) EULA content/TPM password/crash reporting).
 // - update screen.
 class OobeUI : public OobeDisplay,
                public ChromeWebUI {
@@ skipping 15 matching lines @@
   // Collects localized strings from the owned handlers.
   void GetLocalizedStrings(base::DictionaryValue* localized_strings);
 
   // Initializes the handlers.
   void InitializeHandlers();
 
   // Shows or hides OOBE UI elements.
   void ShowOobeUI(bool show);
 
   // Shows the signin screen.
-  void ShowSigninScreen();
+  void ShowSigninScreen(SigninScreenHandlerDelegate* delegate);
 
   // Called when the login main frame has been rendered.
   void OnLoginPromptVisible();
 
  private:
   void AddScreenHandler(BaseScreenHandler* handler);
 
   // Reference to CoreOobeHandler that handles common requests of Oobe page.
   CoreOobeHandler* core_handler_;
 
   // Screens actors. Note, OobeUI owns them via |handlers_|, not directly here.
   UpdateScreenActor* update_screen_actor_;
   NetworkScreenActor* network_screen_actor_;
   EulaScreenActor* eula_screen_actor_;
   EnterpriseEnrollmentScreenActor* enterprise_enrollment_screen_actor_;
 
   // Reference to SigninScreenHandler that handles sign-in screen requrests and
   // forward calls from native code to JS side.
   SigninScreenHandler* signin_screen_handler_;
   UserImageScreenActor* user_image_screen_actor_;
 
   DISALLOW_COPY_AND_ASSIGN(OobeUI);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_OOBE_UI_H_