Implementing CustomElement's attributeChanged callback.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 7bbd1a677bb74281a0031f9b8fe70639d70bd717..6c9cfd93199278fe2286c1d9e5b1bc7d7ed3385a 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -9287,6 +9287,11 @@ abstract class Element extends Node implements ParentNode, ChildNode native "Ele
   @Experimental()
   void leftView() {}
 
+  /**
+   * Called by the DOM whenever an attribute on this has been changed.
+   */
+  void attributeChanged(String name, String oldValue, String newValue) {}
+
   // Hooks to support custom WebComponents.
 
   @Creates('Null')  // Set from Dart code; does not instantiate a native type.
@@ -32543,6 +32548,9 @@ _callEnteredView(receiver) {
 _callLeftView(receiver) {
   return receiver.leftView();
 }
+ _callAttributeChanged(receiver, name, oldValue, newValue) {
+  return receiver.attributeChanged(name, oldValue, newValue);
+}
 
 _makeCallbackMethod(callback) {
   return JS('',
@@ -32554,6 +32562,16 @@ _makeCallbackMethod(callback) {
       convertDartClosureToJS(callback, 1));
 }
 
+_makeCallbackMethod3(callback) {
+  return JS('',
+      '''((function(invokeCallback) {
+             return function(arg1, arg2, arg3) {
+               return invokeCallback(this, arg1, arg2, arg3);
+             };
+          })(#))''',
+      convertDartClosureToJS(callback, 4));
+}
+
 const _typeNameToTag = const {
   'HTMLAnchorElement': 'a',
   'HTMLAudioElement': 'audio',
@@ -32619,6 +32637,8 @@ void _registerCustomElement(context, document, String tag, Type type,
       JS('=Object', '{value: #}', _makeCallbackMethod(_callEnteredView)));
   JS('void', '#.leftViewCallback = #', properties,
       JS('=Object', '{value: #}', _makeCallbackMethod(_callLeftView)));
+  JS('void', '#.attributeChangedCallback = #', properties,
+      JS('=Object', '{value: #}', _makeCallbackMethod3(_callAttributeChanged)));
 
   // TODO(blois): Bug 13220- remove once transition is complete
   JS('void', '#.enteredDocumentCallback = #', properties,