Implement Document.defaultView - fixes #4518

components/script/dom/document.rs

@@ -994,6 +994,11 @@ impl<'a> DocumentMethods for JSRef<'a, Document> {
         self.ready_state.get()
     }
 
+    // https://html.spec.whatwg.org/multipage/browsers.html#dom-document-defaultview
+    fn DefaultView(self) -> Temporary<Window> {
+        Temporary::new(self.window)
+    }
+
     global_event_handlers!()
     event_handler!(readystatechange, GetOnreadystatechange, SetOnreadystatechange)
 }

components/script/dom/webidls/Document.webidl

@@ -84,5 +84,8 @@ partial interface Document {
 
   // special event handler IDL attributes that only apply to Document objects
   [LenientThis] attribute EventHandler onreadystatechange;
+
+  // user interaction
+  readonly attribute Window defaultView;
 };
 Document implements GlobalEventHandlers;