Remove DirectoryException and LinkException from dart:io and use FileException instaed.

sdk/lib/_internal/pub/lib/src/barback/server.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.
 
 library pub.barback.server;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 91 matching lines @@
           // information and so scheduled_test knows we haven't timed out while
           // loading transformers.
           _logRequest(request, "Served $id");
           request.response.close();
         });
       }).catchError((error) {
         _resultsController.add(
             new BarbackServerResult._failure(request.uri, id, error));
 
         // If we couldn't read the asset, handle the error gracefully.
-        if (error is FileException) {
+        if (error is FileSystemException) {
           // Assume this means the asset was a file-backed source asset
           // and we couldn't read it, so treat it like a missing asset.
           _notFound(request, error);
           return;
         }
 
         var trace = new Trace.from(getAttachedStackTrace(error));
         _logRequest(request, "$error\n$trace");
 
         // Otherwise, it's some internal error.
@@ skipping 158 matching lines @@
   bool get isSuccess => error == null;
 
   /// Whether the request was served unsuccessfully.
   bool get isFailure => !isSuccess;
 
   BarbackServerResult._success(this.url, this.id)
       : error = null;
 
   BarbackServerResult._failure(this.url, this.id, this.error);
 }