servo: Merge #4443 - Make the argument to dispatch_event_with_target non-optional (from Ms2ger:dispatch_event_with_target); r=Manishearth

The name of the method makes it clear it's supposed to be used with a target
override, so we might as well enforce that.

Source-Repo: https://github.com/servo/servo
Source-Revision: 11b27361c9f6af08ed78fa1a3fe58732b4c69cd4

servo/components/script/script_task.rs

@@ -859,7 +859,7 @@ impl ScriptTask {
                                EventBubbles::DoesNotBubble,
                                EventCancelable::NotCancelable).root();
         let wintarget: JSRef<EventTarget> = EventTargetCast::from_ref(*window);
-        let _ = wintarget.dispatch_event_with_target(Some(doctarget), *event);
+        let _ = wintarget.dispatch_event_with_target(doctarget, *event);
 
         *page.fragment_name.borrow_mut() = final_url.fragment.clone();