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

sdk/lib/_internal/pub/lib/src/utils.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.
 
 /// Generic utility functions. Stuff that should possibly be in core.
 library pub.utils;
 
 import 'dart:async';
 import "dart:collection";
 import "dart:convert";
@@ skipping 695 matching lines @@
 /// All the names of user-facing exceptions.
 final _userFacingExceptions = new Set<String>.from([
   'ApplicationException',
   // Errors coming from the Dart analyzer are probably caused by syntax errors
   // in user code, so they're user-facing.
   'AnalyzerError', 'AnalyzerErrorGroup',
   // An error spawning an isolate probably indicates a transformer with an
   // invalid import.
   'IsolateSpawnException',
   // TODO(nweiz): clean up the dart:io errors when issue 9955 is fixed.
-  'DirectoryException', 'FileException', 'HttpException', 'HttpException',
-  'LinkException', 'OSError', 'ProcessException', 'SocketException',
-  'WebSocketException'
+  'FileSystemException', 'HttpException', 'HttpException', 'OSError',
+  'ProcessException', 'SocketException', 'WebSocketException'
 ]);
 
 /// Returns whether [error] is a user-facing error object. This includes both
 /// [ApplicationException] and any dart:io errors.
 bool isUserFacingException(error) {
   if (error is CrossIsolateException) {
     return _userFacingExceptions.contains(error.type);
   }
 
   // TODO(nweiz): unify this list with _userFacingExceptions when issue 5897 is
   // fixed.
   return error is ApplicationException ||
     error is AnalyzerError ||
     error is AnalyzerErrorGroup ||
     error is IsolateSpawnException ||
-    error is DirectoryException ||
-    error is FileException ||
+    error is FileSystemException ||
     error is HttpException ||
     error is HttpException ||
-    error is LinkException ||
     error is OSError ||
     error is ProcessException ||
     error is SocketException ||
     error is WebSocketException;
 }