Revert of Fold UpdateModel into UpdateScreen.

chrome/browser/chromeos/login/screens/mock_update_screen.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_SCREENS_MOCK_UPDATE_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_MOCK_UPDATE_SCREEN_H_
 
 #include "chrome/browser/chromeos/login/screens/base_screen_delegate.h"
+#include "chrome/browser/chromeos/login/screens/update_model.h"
 #include "chrome/browser/chromeos/login/screens/update_screen.h"
 #include "chrome/browser/chromeos/login/screens/update_view.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace chromeos {
 
 class MockUpdateScreen : public UpdateScreen {
  public:
   MockUpdateScreen(BaseScreenDelegate* base_screen_delegate, UpdateView* view);
   virtual ~MockUpdateScreen();
 
   MOCK_METHOD0(StartNetworkCheck, void());
 };
 
 class MockUpdateView : public UpdateView {
  public:
   MockUpdateView();
   virtual ~MockUpdateView();
 
-  void Bind(UpdateScreen* screen) override;
+  void Bind(UpdateModel& model) override;
   void Unbind() override;
 
   MOCK_METHOD0(Show, void());
   MOCK_METHOD0(Hide, void());
-  MOCK_METHOD1(MockBind, void(UpdateScreen* screen));
+  MOCK_METHOD1(MockBind, void(UpdateModel& model));
   MOCK_METHOD0(MockUnbind, void());
 
  private:
-  UpdateScreen* screen_ = nullptr;
+  UpdateModel* model_;
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREENS_MOCK_UPDATE_SCREEN_H_