Revert of Fold UpdateModel into UpdateScreen.

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

Index: chrome/browser/chromeos/login/screens/mock_update_screen.cc
diff --git a/chrome/browser/chromeos/login/screens/mock_update_screen.cc b/chrome/browser/chromeos/login/screens/mock_update_screen.cc
index 8b5df54a603c1b57947f20a21802c0c507a84744..02da115ddc08645031cd73fafb367f9b7c095bdf 100644
--- a/chrome/browser/chromeos/login/screens/mock_update_screen.cc
+++ b/chrome/browser/chromeos/login/screens/mock_update_screen.cc
@@ -17,22 +17,22 @@
 MockUpdateScreen::~MockUpdateScreen() {
 }
 
-MockUpdateView::MockUpdateView() {
+MockUpdateView::MockUpdateView() : model_(nullptr) {
   EXPECT_CALL(*this, MockBind(_)).Times(AtLeast(1));
 }
 
 MockUpdateView::~MockUpdateView() {
-  if (screen_)
-    screen_->OnViewDestroyed(this);
+  if (model_)
+    model_->OnViewDestroyed(this);
 }
 
-void MockUpdateView::Bind(UpdateScreen* screen) {
-  screen_ = screen;
-  MockBind(screen);
+void MockUpdateView::Bind(UpdateModel& model) {
+  model_ = &model;
+  MockBind(model);
 }
 
 void MockUpdateView::Unbind() {
-  screen_ = nullptr;
+  model_ = nullptr;
   MockUnbind();
 }