Re-work <dialog>#show*() focus algorithm

third_party/WebKit/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 755 matching lines @@
   void setTabIndexExplicitly();
   // Subclasses may override this method to affect focusability. This method
   // must be called on an up-to-date ComputedStyle, so it may use existence of
   // layoutObject and the LayoutObject::style() to reason about focusability.
   // However, it must not retrieve layout information like position and size.
   // This method cannot be moved to LayoutObject because some focusable nodes
   // don't have layoutObjects. e.g., HTMLOptionElement.
   // TODO(tkent): Rename this to isFocusableStyle.
   virtual bool layoutObjectIsFocusable() const;
 
+  bool hasTabIndex() const { return hasElementFlag(TabIndexWasSetExplicitly); }
+
   // classAttributeChanged() exists to share code between
   // parseAttribute (called via setAttribute()) and
   // svgAttributeChanged (called when element.className.baseValue is set)
   void classAttributeChanged(const AtomicString& newClassString);
 
   static bool attributeValueIsJavaScriptURL(const Attribute&);
 
   PassRefPtr<ComputedStyle> originalStyleForLayoutObject();
 
   Node* insertAdjacent(const String& where, Node* newChild, ExceptionState&);
@@ skipping 390 matching lines @@
 #define DECLARE_ELEMENT_FACTORY_WITH_TAGNAME(T) \
   static T* create(const QualifiedName&, Document&)
 #define DEFINE_ELEMENT_FACTORY_WITH_TAGNAME(T)                     \
   T* T::create(const QualifiedName& tagName, Document& document) { \
     return new T(tagName, document);                               \
   }
 
 }  // namespace blink
 
 #endif  // Element_h