Remove the old signature of NotificationManager::closePersistent().

content/child/notifications/notification_manager.cc

Index: content/child/notifications/notification_manager.cc
diff --git a/content/child/notifications/notification_manager.cc b/content/child/notifications/notification_manager.cc
index 40ad89efb20115ddfb4fdba4a48e4f982cad2d38..b951ba720cc957e5d0ba0c60291305c809f90985 100644
--- a/content/child/notifications/notification_manager.cc
+++ b/content/child/notifications/notification_manager.cc
@@ -141,11 +141,6 @@ void NotificationManager::closePersistent(
       base::UTF16ToUTF8(persistent_notification_id)));
 }
 
-void NotificationManager::closePersistent(
-    const blink::WebString& persistent_notification_id) {
-  closePersistent(blink::WebSerializedOrigin(), persistent_notification_id);
-}
-
 void NotificationManager::notifyDelegateDestroyed(
     blink::WebNotificationDelegate* delegate) {
   if (pending_notifications_.CancelPageNotificationFetches(delegate))