Implement 'tabstop' as an HTML attribute

Source/core/dom/Element.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003-2011, 2013, 2014 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
@@ skipping 61 matching lines @@
     SpellcheckAttributeDefault
 };
 
 enum ElementFlags {
     TabIndexWasSetExplicitly = 1 << 0,
     StyleAffectedByEmpty = 1 << 1,
     IsInCanvasSubtree = 1 << 2,
     ContainsFullScreenElement = 1 << 3,
     IsInTopLayer = 1 << 4,
     HasPendingResources = 1 << 5,
+    TabStopWasSetExplicitly = 1 << 6,
 
-    NumberOfElementFlags = 6, // Required size of bitfield used to store the flags.
+    NumberOfElementFlags = 7, // Required size of bitfield used to store the flags.
 };
 
 class CORE_EXPORT Element : public ContainerNode {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<Element> create(const QualifiedName&, Document*);
     virtual ~Element();
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(beforecopy);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(beforecut);
@@ skipping 276 matching lines @@
     virtual void blur();
     // Whether this element can receive focus at all. Most elements are not
     // focusable but some elements, such as form controls and links, are. Unlike
     // layoutObjectIsFocusable(), this method may be called when layout is not up to
     // date, so it must not use the renderer to determine focusability.
     virtual bool supportsFocus() const;
     // Whether the node can actually be focused.
     bool isFocusable() const;
     bool tabStop() const;
     void setTabStop(bool);
+    void setTabStopInternal(bool);
     virtual bool isKeyboardFocusable() const;
     virtual bool isMouseFocusable() const;
     virtual void dispatchFocusEvent(Element* oldFocusedElement, WebFocusType);
     virtual void dispatchBlurEvent(Element* newFocusedElement, WebFocusType);
     virtual void dispatchFocusInEvent(const AtomicString& eventType, Element* oldFocusedElement, WebFocusType);
     void dispatchFocusOutEvent(const AtomicString& eventType, Element* newFocusedElement);
 
     String innerText();
     String outerText();
     String innerHTML() const;
@@ skipping 492 matching lines @@
     static PassRefPtrWillBeRawPtr<T> create(const QualifiedName&, Document&)
 #define DEFINE_ELEMENT_FACTORY_WITH_TAGNAME(T) \
     PassRefPtrWillBeRawPtr<T> T::create(const QualifiedName& tagName, Document& document) \
     { \
         return adoptRefWillBeNoop(new T(tagName, document)); \
     }
 
 } // namespace
 
 #endif // Element_h