[dart:io] Adds functions to set file access and modification time

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 50 matching lines @@
   bool existsSync() {
     var result = _exists(path);
     if (result is OSError) {
       throw new FileSystemException("Exists failed", path, result);
     }
     return (result == 1);
   }
 
   Directory get absolute => new Directory(_absolutePath);
 
-  Future<FileStat> stat() => FileStat.stat(path);
-
-  FileStat statSync() => FileStat.statSync(path);
-
   Future<Directory> create({bool recursive: false}) {
     if (recursive) {
       return exists().then((exists) {
         if (exists) return this;
         if (path != parent.path) {
           return parent.create(recursive: true).then((_) {
             return create();
           });
         } else {
           return create();
@@ skipping 310 matching lines @@
       controller.addError(
           new FileSystemException("Directory listing failed",
                                   errorPath,
                                   err));
     } else {
       controller.addError(
           new FileSystemException("Internal error"));
     }
   }
 }