Fix listing of '' and '/'.

sdk/lib/io/directory_impl.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.io;
 
 class _Directory extends FileSystemEntity implements Directory {
   final String path;
 
   _Directory(this.path) {
@@ skipping 195 matching lines @@
     var result = _rename(path, newPath);
     if (result is OSError) {
       throw new FileSystemException("Rename failed", path, result);
     }
     return new Directory(newPath);
   }
 
   Stream<FileSystemEntity> list({bool recursive: false,
                                  bool followLinks: true}) {
     return new _AsyncDirectoryLister(
-        FileSystemEntity._trimTrailingPathSeparators(path),
+        FileSystemEntity._ensureTrailingPathSeparators(path),
         recursive,
         followLinks).stream;
   }
 
   List listSync({bool recursive: false, bool followLinks: true}) {
     if (recursive is! bool || followLinks is! bool) {
       throw new ArgumentError();
     }
     return _list(
-        FileSystemEntity._trimTrailingPathSeparators(path),
+        FileSystemEntity._ensureTrailingPathSeparators(path),
         recursive,
         followLinks);
   }
 
   String toString() => "Directory: '$path'";
 
   bool _isErrorResponse(response) =>
       response is List && response[0] != _SUCCESS_RESPONSE;
 
   _exceptionOrErrorFromResponse(response, String message) {
@@ skipping 140 matching lines @@
       controller.addError(
           new FileSystemException("Directory listing failed",
                                  errorPath,
                                  err));
     } else {
       controller.addError(
           new FileSystemException("Internal error"));
     }
   }
 }