Implement WebIDL implements

Source/core/dom/DocumentFragment.idl

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 [
     Constructor,
     ConstructorCallWith=ScriptExecutionContext
 ] interface DocumentFragment : Node {
     // NodeSelector - Selector API
     [RaisesException] Element querySelector(DOMString selectors);
     [RaisesException] NodeList querySelectorAll(DOMString selectors);
-
-    // ParentNode interface API
-    readonly attribute HTMLCollection children;
-    readonly attribute Element firstElementChild;
-    readonly attribute Element lastElementChild;
-    readonly attribute unsigned long childElementCount;
 };