Supports "class string" based on @@toStringTag.

third_party/WebKit/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 165 matching lines @@
     attribute EventHandler onsearch;
     attribute EventHandler ontransitionend;
     attribute EventHandler onwebkitanimationend;
     attribute EventHandler onwebkitanimationiteration;
     attribute EventHandler onwebkitanimationstart;
     attribute EventHandler onwebkittransitionend;
     attribute EventHandler onwheel;
 
     // https://w3c.github.io/webappsec/specs/powerfulfeatures/#monkey-patching-global-object
     readonly attribute boolean isSecureContext;
-
-    // window.toString() requires special handling in V8
-    [DoNotCheckSignature, DoNotCheckSecurity, Custom, NotEnumerable] stringifier;
 };
 
 // http://www.whatwg.org/specs/web-apps/current-work/#transferable-objects
 //
 // Expressing the Transferable typedef in IDL depends on http://crbug.com/240176.
 // The postMessage() methods taking a Transferable array argument have custom
 // binding code that is able to handle the Transferables that we currently
 // recognize. To be able to declare a postMessage() signature that matches
 // the implementation, we provide a Transferable typedef but with an
 // incomplete type.
 //
 // FIXME: make this typedef accurate once enough of http://crbug.com/240176
 // is in place.
 // FIXME: consider putting this typedef in an .idl file containing spec-wide
 // utility type definitions.
 typedef MessagePort Transferable;
 
 Window implements GlobalEventHandlers;
 Window implements WindowBase64;
 Window implements WindowEventHandlers;
 Window implements WindowTimers;