Moves over remaining .dart code references to 'factory' in interface declartions to 'default'

client/html/src/Element.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 interface ElementList extends List<Element> {
   // TODO(jacobr): add element batch manipulation methods.
   Element get first();
   // TODO(jacobr): add insertAt
 }
 
@@ skipping 56 matching lines @@
 interface ElementRect {
   ClientRect get client();
   ClientRect get offset();
   ClientRect get scroll();
   ClientRect get bounding();
   List<ClientRect> get clientRects();
 }
 
 
 interface Element extends Node /*, common.NodeSelector, common.ElementTraversal */
-    factory ElementWrappingImplementation {
+    default ElementWrappingImplementation {
 
   Element.html(String html);
   Element.tag(String tag);
 
   Map<String, String> get attributes();
   void set attributes(Map<String, String> value);
 
   ElementList get elements();
 
   // TODO: The type of value should be Collection<Element>. See http://b/5392897
@@ skipping 98 matching lines @@
   bool matchesSelector([String selectors]);
 
   Future<ElementRect> get rect();
 
   Future<CSSStyleDeclaration> get computedStyle();
 
   Future<CSSStyleDeclaration> getComputedStyle(String pseudoElement);
 
   ElementEvents get on();
 }