Implement update notifications for ChromeVox Next.

ui/message_center/views/message_center_view.cc

Index: ui/message_center/views/message_center_view.cc
diff --git a/ui/message_center/views/message_center_view.cc b/ui/message_center/views/message_center_view.cc
index 3555b1a891ac98b6f495eab7a8c820da3ff64006..d2dc4e118e9697cc21bd481eff07ab3ec35f75a1 100644
--- a/ui/message_center/views/message_center_view.cc
+++ b/ui/message_center/views/message_center_view.cc
@@ -528,16 +528,6 @@ void MessageCenterView::Update(bool animate) {
   else
     SetVisibilityMode(Mode::NOTIFICATIONS, animate);
 
-  if (no_message_views) {
-    scroller_->SetFocusBehavior(FocusBehavior::NEVER);
-  } else {
-#if defined(OS_MACOSX)
-    scroller_->SetFocusBehavior(FocusBehavior::ACCESSIBLE_ONLY);
-#else
-    scroller_->SetFocusBehavior(FocusBehavior::ALWAYS);
-#endif
-  }
-
   UpdateButtonBarStatus();
 
   if (focus_manager && focused_view)