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

client/html/src/TouchEvent.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 TouchEvent extends UIEvent factory TouchEventWrappingImplementation {
+interface TouchEvent extends UIEvent default TouchEventWrappingImplementation {
 
   TouchEvent(TouchList touches, TouchList targetTouches,
       TouchList changedTouches, String type, Window view, int screenX,
       int screenY, int clientX, int clientY, [bool ctrlKey, bool altKey,
       bool shiftKey, bool metaKey]);
 
   bool get altKey();
 
   TouchList get changedTouches();
 
   bool get ctrlKey();
 
   bool get metaKey();
 
   bool get shiftKey();
 
   TouchList get targetTouches();
 
   TouchList get touches();
 }