Fix File:openRead and file_input_stream_test.

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 108 matching lines @@
           _closeFile();
           _unsubscribed = true;
         }
       });
   }
 
   void _start() {
     if (_position < 0) {
       _controller.addError(new RangeError("Bad start position: $_position"));
       _controller.close();
+      _closeCompleter.complete();
       return;
     }
 
     void onReady(RandomAccessFile file) {
       _openedFile = file;
       _readInProgress = false;
       _readBlock();
     }
 
     void onOpenFile(RandomAccessFile file) {
@@ skipping 782 matching lines @@
   void _checkAvailable() {
     if (_asyncDispatched) {
       throw new FileSystemException("An async operation is currently pending",
                                     path);
     }
     if (closed) {
       throw new FileSystemException("File closed", path);
     }
   }
 }