Add <menuitem>, new HTMLMenuElement IDL attributes.

Source/core/html/HTMLElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004-2008, 2013, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Motorola Mobility. 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 84 matching lines @@
         || hasTagName(basefontTag)
         || hasTagName(brTag)
         || hasTagName(colTag)
         || hasTagName(embedTag)
         || hasTagName(frameTag)
         || hasTagName(hrTag)
         || hasTagName(imageTag)
         || hasTagName(imgTag)
         || hasTagName(inputTag)
         || hasTagName(linkTag)
+        || (RuntimeEnabledFeatures::contextMenuEnabled() && hasTagName(menuitemTag))
         || hasTagName(metaTag)
         || hasTagName(paramTag)
         || hasTagName(sourceTag)
         || hasTagName(wbrTag))
         return true;
     return false;
 }
 
 static inline CSSValueID unicodeBidiAttributeForDirAuto(HTMLElement* element)
 {
@@ skipping 843 matching lines @@
 #ifndef NDEBUG
 
 // For use in the debugger
 void dumpInnerHTML(blink::HTMLElement*);
 
 void dumpInnerHTML(blink::HTMLElement* element)
 {
     printf("%s\n", element->innerHTML().ascii().data());
 }
 #endif