IDL: Support 'stringifier' keyword

Source/core/frame/Window.idl

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 187 matching lines @@
     [MeasureAs=WindowCaptureEvents] void captureEvents();
     [MeasureAs=WindowReleaseEvents] void releaseEvents();
 
     // Additional constructors.
     [MeasureAs=PrefixedTransitionEventConstructor] attribute TransitionEventConstructor WebKitTransitionEvent;
     [RuntimeEnabled=CSSAnimationUnprefixed] attribute WebKitAnimationEventConstructor AnimationEvent;
     [MeasureAs=PrefixedWindowURL] attribute URLConstructor webkitURL; // FIXME: deprecate this.
     [MeasureAs=PrefixedMutationObserverConstructor] attribute MutationObserverConstructor WebKitMutationObserver;
 
     // window.toString() requires special handling in V8
-    [DoNotCheckSignature, DoNotCheckSecurity, Custom, NotEnumerable] DOMString toString();
+    [DoNotCheckSignature, DoNotCheckSecurity, Custom, NotEnumerable] stringifier;
 
     [NotEnumerable] getter Window (unsigned long index);
     [Custom, NotEnumerable] getter Window (DOMString name);
 };
 
 Window implements GlobalEventHandlers;
 Window implements WindowBase64;
 Window implements WindowEventHandlers;
 Window implements WindowTimers;