Remove AsyncError with Expando.

sdk/lib/io/file_impl.dart

 // Copyright (c) 2013, 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.io;
 
 // Read the file in blocks of size 64k.
 const int _BLOCK_SIZE = 64 * 1024;
 
 
@@ skipping 18 matching lines @@
 
   _FileStream(String this._path) : _position = 0 {
     _setupController();
   }
 
   _FileStream.forStdin() : _position = 0 {
     _setupController();
   }
 
   StreamSubscription<List<int>> listen(void onData(List<int> event),
-                                       {void onError(AsyncError error),
+                                       {void onError(error),
                                         void onDone(),
                                         bool cancelOnError}) {
     return _controller.stream.listen(onData,
                                      onError: onError,
                                      onDone: onDone,
                                      cancelOnError: cancelOnError);
   }
 
   void _setupController() {
     _controller = new StreamController<List<int>>(
@@ skipping 988 matching lines @@
           new FileIOException("File closed '$_path'"));
     });
     return completer.future;
   }
 
   final String _path;
   int _id;
 
   SendPort _fileService;
 }