Call .created constructor on dart2js custom elements

tools/dom/src/dart2js_CustomElementSupport.dart

Index: tools/dom/src/dart2js_CustomElementSupport.dart
diff --git a/tools/dom/src/dart2js_CustomElementSupport.dart b/tools/dom/src/dart2js_CustomElementSupport.dart
index a3fa0bf1360ec05df789d057c278c12991f59646..8edecc44a8edc2fd472ef40f9c7234c5a7b5dab6 100644
--- a/tools/dom/src/dart2js_CustomElementSupport.dart
+++ b/tools/dom/src/dart2js_CustomElementSupport.dart
@@ -4,8 +4,10 @@
 
 part of dart.dom.html;
 
-_callCreated(receiver) {
-  return receiver.createdCallback();
+_callConstructor(constructor) {
+  return (receiver) {
+    return JS('', '#(#)', constructor, receiver);
+  };
 }
 
 _callEnteredView(receiver) {
@@ -84,6 +86,11 @@ void _registerCustomElement(context, document, String tag, Type type,
     throw new ArgumentError(type);
   }
 
+  var constructor = findConstructorForWebComponentType(type, 'created');
+  if (constructor == null) {
+    throw new ArgumentError("$type has no constructor called 'created'");
+  }
+
   // Workaround for 13190- use an article element to ensure that HTMLElement's
   // interceptor is resolved correctly.
   getNativeInterceptor(new Element.tag('article'));
@@ -99,7 +106,8 @@ void _registerCustomElement(context, document, String tag, Type type,
   var properties = JS('=Object', '{}');
 
   JS('void', '#.createdCallback = #', properties,
-      JS('=Object', '{value: #}', _makeCallbackMethod(_callCreated)));
+      JS('=Object', '{value: #}',
+          _makeCallbackMethod(_callConstructor(constructor))));
   JS('void', '#.enteredViewCallback = #', properties,
       JS('=Object', '{value: #}', _makeCallbackMethod(_callEnteredView)));
   JS('void', '#.leftViewCallback = #', properties,