Revert "Ash Tray: Fix quick settings not closing after clicking on a notification."

This reverts commit b622130a.

Reason for revert: This CL causes the crash. See crbug.com/1028848

BUG=1028848

Original change's description:
> Ash Tray: Fix quick settings not closing after clicking on a notification.
> 
> BUG=1024100
> 
> Change-Id: Ib30e43689842069e4647f7f455a919c62a3c7844
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1928042
> Reviewed-by: Ahmed Mehfooz <amehfooz@chromium.org>
> Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#717775}

TBR=amehfooz@chromium.org,tengs@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1024100
Change-Id: I52bf4673a0b7f3142690e80c7bf944f0fd0a2a3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1939135Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Yoshiki Iguchi <yoshiki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719521}

ash/system/unified/unified_system_tray_bubble.cc

@@ -314,13 +314,17 @@ void UnifiedSystemTrayBubble::OnWindowActivated(ActivationReason reason,
     return;
   }
 
-  // Don't close the bubble if the message center is gaining activation.
+  // Don't close the bubble if the message center is gaining or losing
+  // activation.
   if (features::IsUnifiedMessageCenterRefactorEnabled() &&
       tray_->IsMessageCenterBubbleShown()) {
     views::Widget* message_center_widget =
         tray_->message_center_bubble()->GetBubbleWidget();
     if (message_center_widget ==
-        views::Widget::GetWidgetForNativeView(gained_active)) {
+            views::Widget::GetWidgetForNativeView(gained_active) ||
+        (lost_active &&
+         message_center_widget ==
+             views::Widget::GetWidgetForNativeView(lost_active))) {
       return;
     }
   }