Fix message center crashes

This change fixes a number of crashes caused by the message center
widget being destroyed without it's animations being cleaned up
properly.

Change-Id: If70b46d530867721785cd208db937207c6dcc865
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1877256
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709266}

ash/system/message_center/unified_message_center_bubble.cc

@@ -55,10 +55,6 @@ UnifiedMessageCenterBubble::UnifiedMessageCenterBubble(UnifiedSystemTray* tray)
   tray->bubble()->unified_view()->AddObserver(this);
 
   UpdatePosition();
-
-  if (!message_center_view_->GetVisible()) {
-    bubble_widget_->Hide();
-  }
 }
 
 UnifiedMessageCenterBubble::~UnifiedMessageCenterBubble() {
@@ -132,15 +128,6 @@ views::Widget* UnifiedMessageCenterBubble::GetBubbleWidget() const {
   return bubble_widget_;
 }
 
-void UnifiedMessageCenterBubble::OnViewVisibilityChanged(
-    views::View* observed_view,
-    views::View* starting_view) {
-  if (message_center_view_->GetVisible())
-    bubble_widget_->Show();
-  else
-    bubble_widget_->Hide();
-}
-
 void UnifiedMessageCenterBubble::OnViewPreferredSizeChanged(
     views::View* observed_view) {
   UpdatePosition();

ash/system/message_center/unified_message_center_bubble.h

@@ -59,8 +59,6 @@ class ASH_EXPORT UnifiedMessageCenterBubble : public TrayBubbleBase,
   views::Widget* GetBubbleWidget() const override;
 
   // views::ViewObserver:
-  void OnViewVisibilityChanged(views::View* observed_view,
-                               views::View* starting_view) override;
   void OnViewPreferredSizeChanged(views::View* observed_view) override;
 
   // views::WidgetObserver:

ash/system/message_center/unified_message_center_bubble_unittest.cc

@@ -129,20 +129,6 @@ class UnifiedMessageCenterBubbleTest : public AshTestBase {
   DISALLOW_COPY_AND_ASSIGN(UnifiedMessageCenterBubbleTest);
 };
 
-TEST_F(UnifiedMessageCenterBubbleTest, VisibileOnlyWithNotifications) {
-  EnableMessageCenterRefactor();
-  GetPrimaryUnifiedSystemTray()->ShowBubble(true);
-  // UnifiedMessageCenterBubble should not be visible when there are no
-  // notifications.
-  EXPECT_FALSE(GetMessageCenterBubble()->GetBubbleWidget()->IsVisible());
-
-  AddNotification();
-
-  // UnifiedMessageCenterBubble should become visible after a notification is
-  // added.
-  EXPECT_TRUE(GetMessageCenterBubble()->GetBubbleWidget()->IsVisible());
-}
-
 TEST_F(UnifiedMessageCenterBubbleTest, PositionedAboveSystemTray) {
   const int total_notifications = 5;
   EnableMessageCenterRefactor();