Fix code to not hit bug in dart2js.

sdk/lib/async/stream_pipe.dart

 // Copyright (c) 2012, 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.
 
 part of dart.async;
 
 /** Utility function to create an [AsyncError] if [error] isn't one already. */
 AsyncError _asyncError(Object error, Object stackTrace, [AsyncError cause]) {
   if (error is AsyncError) return error;
   if (cause == null) return new AsyncError(error, stackTrace);
@@ skipping 541 matching lines @@
  * A stream transformer that intercepts all events and can generate any event as
  * output.
  *
  * Each incoming event on the source stream is passed to the corresponding
  * provided event handler, along with a [StreamSink] linked to the output
  * Stream.
  * The handler can then decide exactly which events to send to the output.
  */
 class _StreamEventTransformerImpl<S, T>
     implements StreamEventTransformer<S, T> {
-  final _TransformDataHandler<S, T> _handleData;
+  // TODO(ahe): Restore type when feature is implemented in dart2js

[ahe, 2013/01/29 11:00:23]

I'm not sure why this TODO has my name on it?

+  // checked mode. http://dartbug.com/7733
+  final Function /*_TransformDataHandler<S, T>*/ _handleData;
   final _TransformErrorHandler<T> _handleError;
   final _TransformDoneHandler<T> _handleDone;
 
   _StreamEventTransformerImpl(void onData(S data, StreamSink<T> sink),
                               void onError(AsyncError data, StreamSink<T> sink),
                               void onDone(StreamSink<T> sink))
       : this._handleData = (onData == null ? _defaultHandleData : onData),
         this._handleError = (onError == null ? _defaultHandleError : onError),
         this._handleDone = (onDone == null ? _defaultHandleDone : onDone);
 
@@ skipping 14 matching lines @@
   }
 
   void handleDone(StreamSink<T> sink) {
     try {
       _handleDone(sink);
     } catch (e, s) {
       sink.signalError(_asyncError(e, s));
     }
   }
 }