Revert of Fold UpdateModel into UpdateScreen.

chrome/browser/chromeos/login/screens/mock_update_screen.h

Index: chrome/browser/chromeos/login/screens/mock_update_screen.h
diff --git a/chrome/browser/chromeos/login/screens/mock_update_screen.h b/chrome/browser/chromeos/login/screens/mock_update_screen.h
index d69cfe24b15b03bbdfc86293262af1409f9a934d..896eb77e04d1f4167e6247ef768c3d6458d398cf 100644
--- a/chrome/browser/chromeos/login/screens/mock_update_screen.h
+++ b/chrome/browser/chromeos/login/screens/mock_update_screen.h
@@ -6,6 +6,7 @@
 #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"
@@ -25,16 +26,16 @@
   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