Hide the settings button on a notification in MNC.

ui/arc/notification/arc_notification_item.cc

Index: ui/arc/notification/arc_notification_item.cc
diff --git a/ui/arc/notification/arc_notification_item.cc b/ui/arc/notification/arc_notification_item.cc
index 88cda841f630a1aedb19ff857677163d95684b12..5beb310f5232186ab1ec73bb8d811844706edf14 100644
--- a/ui/arc/notification/arc_notification_item.cc
+++ b/ui/arc/notification/arc_notification_item.cc
@@ -275,6 +275,10 @@ void ArcNotificationItem::OpenSettings() {
   manager_->OpenNotificationSettings(notification_key_);
 }
 
+bool ArcNotificationItem::IsOpeningSettingsSupported() const {
+  return manager_->IsOpeningSettingsSupported();
+}
+
 // Converts from Android notification priority to Chrome notification priority.
 // On Android, PRIORITY_DEFAULT does not pop up, so this maps PRIORITY_DEFAULT
 // to Chrome's -1 to adapt that behavior. Also, this maps PRIORITY_LOW and _HIGH