Revert "Revert "Dart2js support for custom element lifecycle events""

tests/html/custom/created_callback_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 created_callback_test;
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
 import 'dart:html';
 import '../utils.dart';
 
@@ skipping 36 matching lines @@
 
     // As per:
     // http://www.w3.org/TR/2013/WD-custom-elements-20130514/#serializing-and-parsing
     // creation order is t, u, v, w (postorder).
     expect(t is C, isTrue);
     // Note, this is different from JavaScript where this would be false.
     expect(v is C, isTrue);
   }
 }
 
-loadPolyfills() {
-  if (!document.supportsRegister) {
-    // Cache blocker is a workaround for:
-    // https://code.google.com/p/dart/issues/detail?id=11834
-    var cacheBlocker = new DateTime.now().millisecondsSinceEpoch;
-    return HttpRequest.getString('/root_dart/pkg/custom_element/lib/'
-      'custom-elements.debug.js?cacheBlock=$cacheBlocker').then((code) {
-      document.head.children.add(new ScriptElement()..text = code);
-    });
-  }
-}
-
 main() {
   useHtmlConfiguration();
 
   // Adapted from Blink's
   // fast/dom/custom/created-callback test.
 
   setUp(loadPolyfills);
 
   test('transfer created callback', () {
     document.register(A.tag, A);
@@ skipping 16 matching lines @@
 
     Platform.upgradeCustomElements(div);
 
     expect(C.createdInvocations, 2);
     expect(div.query('#w') is B, isTrue);
   });
 
   // TODO(vsm): Port additional test from upstream here:
   // http://src.chromium.org/viewvc/blink/trunk/LayoutTests/fast/dom/custom/created-callback.html?r1=156141&r2=156185
 }