Add support for [TreatNullAs] extended attribute for reflected attributes

Source/core/html/HTMLFrameElement.idl

 /*
  * Copyright (C) 2006, 2007, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * 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.
  */
 
 interface HTMLFrameElement : HTMLElement {
 
-    [Reflect] attribute DOMString frameBorder;
-    [Reflect] attribute DOMString longDesc;
-    [Reflect] attribute DOMString marginHeight;
-    [Reflect] attribute DOMString marginWidth;
-    [Reflect] attribute DOMString name;
+    [Reflect, TreatNullAs=NullString] attribute DOMString frameBorder;
+    [Reflect, TreatNullAs=NullString] attribute DOMString longDesc;
+    [Reflect, TreatNullAs=NullString] attribute DOMString marginHeight;
+    [Reflect, TreatNullAs=NullString] attribute DOMString marginWidth;
+    [Reflect, TreatNullAs=NullString] attribute DOMString name;
     [Reflect] attribute boolean noResize;
-    [Reflect] attribute DOMString scrolling;
-    [Reflect, URL] attribute DOMString src;
+    [Reflect, TreatNullAs=NullString] attribute DOMString scrolling;
+    [Reflect, TreatNullAs=NullString, URL] attribute DOMString src;
 
     // Introduced in DOM Level 2:
     [CheckSecurityForNode] readonly attribute Document contentDocument;
 
     // Extensions
     readonly attribute Window contentWindow;
 
     [CheckSecurityForNode, RaisesException] SVGDocument getSVGDocument();
 
     [TreatNullAs=NullString, CustomSetter] attribute DOMString location;
 
     readonly attribute long width;
     readonly attribute long height;
 
 };