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

runtime/bin/file_patch.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.
 
 @patch class _File {
   @patch static _exists(String path) native "File_Exists";
   @patch static _create(String path) native "File_Create";
   @patch static _createLink(String path, String target)
       native "File_CreateLink";
   @patch static _linkTarget(String path) native "File_LinkTarget";
   @patch static _deleteNative(String path) native "File_Delete";
   @patch static _deleteLinkNative(String path) native "File_DeleteLink";
   @patch static _rename(String oldPath, String newPath)
       native "File_Rename";
   @patch static _renameLink(String oldPath, String newPath)
       native "File_RenameLink";
   @patch static _copy(String oldPath, String newPath) native "File_Copy";
   @patch static _lengthFromPath(String path) native "File_LengthFromPath";
   @patch static _lastModified(String path) native "File_LastModified";
+  @patch static _setLastModified(String path, int millis)
+      native "File_SetLastModified";
+  @patch static _lastAccessed(String path) native "File_LastAccessed";
+  @patch static _setLastAccessed(String path, int millis)
+      native "File_SetLastAccessed";
   @patch static _open(String path, int mode) native "File_Open";
   @patch static int _openStdio(int fd) native "File_OpenStdio";
 }
 
 
 @patch class _RandomAccessFileOps {
   @patch factory _RandomAccessFileOps(int pointer)
       => new _RandomAccessFileOpsImpl(pointer);
 }
 
@@ skipping 345 matching lines @@
   void _pathWatchedEnd() {
     _subscription.cancel();
     _controller.close();
   }
 }
 
 
 Uint8List _makeUint8ListView(Uint8List source, int offsetInBytes, int length) {
   return new Uint8List.view(source.buffer, offsetInBytes, length);
 }