Revert of Fold UpdateModel into UpdateScreen.

chrome/browser/ui/webui/chromeos/login/update_screen_handler.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_UI_WEBUI_CHROMEOS_LOGIN_UPDATE_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_UPDATE_SCREEN_HANDLER_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "chrome/browser/chromeos/login/screens/update_view.h"
 #include "chrome/browser/ui/webui/chromeos/login/base_screen_handler.h"
 
 namespace chromeos {
 
 class UpdateScreenHandler : public UpdateView, public BaseScreenHandler {
  public:
   UpdateScreenHandler();
   ~UpdateScreenHandler() override;
 
- private:
   // UpdateView:
   void Show() override;
   void Hide() override;
-  void Bind(UpdateScreen* screen) override;
+  void Bind(UpdateModel& model) override;
   void Unbind() override;
 
   // BaseScreenHandler:
   void DeclareLocalizedValues(
       ::login::LocalizedValuesBuilder* builder) override;
   void Initialize() override;
 
-  UpdateScreen* screen_ = nullptr;
+ private:
+  UpdateModel* model_;
 
-  // If true, Initialize() will call Show().
-  bool show_on_init_ = false;
+  // Keeps whether screen should be shown right after initialization.
+  bool show_on_init_;
 
   DISALLOW_COPY_AND_ASSIGN(UpdateScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_UPDATE_SCREEN_HANDLER_H_