Adding Element.created constructor

tests/html/custom/document_register_basic_test.dart

 // Copyright (c) 2013, 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.
 
 library document_register_basic_test;
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
 import 'dart:html';
 import '../utils.dart';
 
 class Foo extends HtmlElement {
   static final tag = 'x-foo';
   factory Foo() => new Element.tag(tag);
+  Foo.created() : super.created();
 
   get thisIsACustomClass => true;
 }
 
 class Bar extends HtmlElement {
   static final tag = 'x-bar';
   factory Bar() => new Element.tag(tag);
+  Bar.created() : super.created();
 
   get thisIsACustomClass => true;
 }
 
 class Baz extends Foo {
   static final tag = 'x-baz';
   factory Baz() => new Element.tag(tag);
+  Baz.created() : super.created();
 
   get thisIsAlsoACustomClass => true;
 }
 
 class BadB {
 }
 
 class BadE implements HtmlElement {
   static final tag = 'x-tag-e';
   factory BadE() => new Element.tag(tag);
+  BadE.created() : super.created();
 }
 
 main() {
   useHtmlConfiguration();
 
   // Adapted from Blink's fast/dom/custom/document-register-basic test.
 
   setUp(loadPolyfills);
 
   test('Testing document.register() basic behaviors', () {
@@ skipping 81 matching lines @@
     expect(container.firstChild.tagName, "X-BAR");
     expect(container.lastChild is Bar, isTrue);
     expect(container.lastChild.tagName, "X-BAR");
 
     // Constructors shouldn't interfere with each other
     expect((new Foo()).tagName, "X-FOO");
     expect((new Bar()).tagName, "X-BAR");
     expect((new Baz()).tagName, "X-BAZ");
   });
 }