Remove AsyncError with Expando.

tools/dom/src/EventStreamProvider.dart

Index: tools/dom/src/EventStreamProvider.dart
diff --git a/tools/dom/src/EventStreamProvider.dart b/tools/dom/src/EventStreamProvider.dart
index d1a341277df94b9f5ad05f42fa2da062f3f689bc..788b179e1e99aa80c19b43a956993adbaa7bd66f 100644
--- a/tools/dom/src/EventStreamProvider.dart
+++ b/tools/dom/src/EventStreamProvider.dart
@@ -19,9 +19,9 @@ class _EventStream<T extends Event> extends Stream<T> {
   bool get isBroadcast => true;
 
   StreamSubscription<T> listen(void onData(T event),
-      { void onError(AsyncError error),
-      void onDone(),
-      bool cancelOnError}) {
+      { void onError(error),
+        void onDone(),
+        bool cancelOnError}) {
 
     return new _EventStreamSubscription<T>(
         this._target, this._eventType, onData, this._useCapture);
@@ -63,7 +63,7 @@ class _EventStreamSubscription<T extends Event> extends StreamSubscription<T> {
   }
 
   /// Has no effect.
-  void onError(void handleError(AsyncError error)) {}
+  void onError(void handleError(error)) {}
 
   /// Has no effect.
   void onDone(void handleDone()) {}