Add isTabStop attribute to Element

Source/core/dom/Element.idl

 /*
  * Copyright (C) 2006, 2007, 2009 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,
@@ skipping 94 matching lines @@
 
     [PerWorldBindings] readonly attribute DOMStringMap dataset;
 
     // WebKit extension
     [RaisesException, ImplementedAs=matches, MeasureAs=ElementPrefixedMatchesSelector] boolean webkitMatchesSelector(DOMString selectors);
 
     // Shadow DOM API
     [RaisesException, MeasureAs=ElementCreateShadowRoot] ShadowRoot createShadowRoot();
     [PerWorldBindings] readonly attribute ShadowRoot shadowRoot;
     NodeList getDestinationInsertionPoints();
+    [RuntimeEnabled=IsTabStopAttribute] attribute boolean isTabStop;
 
     // CSSOM View Module API
     ClientRectList getClientRects();
     ClientRect getBoundingClientRect();
 
     [MeasureAs=ElementRequestPointerLock] void requestPointerLock();
 
     // Experimental accessibility API
     [RuntimeEnabled=ComputedAccessibilityInfo] readonly attribute DOMString? computedRole;
     [RuntimeEnabled=ComputedAccessibilityInfo] readonly attribute DOMString? computedName;
@@ skipping 10 matching lines @@
     [RuntimeEnabled=Touch] attribute EventHandler ontouchcancel;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchend;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchmove;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchstart;
     attribute EventHandler onwheel;
 };
 
 Element implements ParentNode;
 Element implements ChildNode;
 Element implements NonDocumentTypeChildNode;