dart:html perf optimization based on runing Dromaeo benchmarks

lib/html/src/frog_FactoryProviders.dart

 // Copyright (c) 2012, 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.
 
 class _AudioContextFactoryProvider {
 
   factory AudioContext() native '''
     var constructor = window.AudioContext || window.webkitAudioContext;
     return new constructor();
 ''';
@@ skipping 52 matching lines @@
 
 class _PointFactoryProvider {
 
   factory Point(num x, num y) native 'return new WebKitPoint(x, y);';
 }
 
 class _WebSocketFactoryProvider {
 
   factory WebSocket(String url) native '''return new WebSocket(url);''';
 }
+
+class _TextFactoryProvider {
+  factory Text(String data) native "return document.createTextNode(data);";
+}