Adding Element.created constructor

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 aa2c8f039af3153f2271d9c2139c50c96cb0507e..c708105d93c4ce476b12b59fed3cb4e860919ef0 100644
--- a/tools/dom/src/dart2js_CustomElementSupport.dart
+++ b/tools/dom/src/dart2js_CustomElementSupport.dart
@@ -5,7 +5,7 @@
 part of dart.dom.html;
 
 _callCreated(receiver) {
-  return receiver.created();
+  return receiver.createdCallback();
 }
 
 _callEnteredView(receiver) {
@@ -117,3 +117,8 @@ void _registerCustomElement(context, document, String tag, Type type,
 
   JS('void', '#.register(#, #)', document, tag, options);
 }
+
+//// Called by Element.created to do validation & initialization.
+void _initializeCustomElement(Element e) {
+  // TODO(blois): Add validation that this is only in response to an upgrade.
+}