Implement type=radio and radiogroup attribute for menuitem.

Source/core/html/HTMLMenuItemElement.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/html/HTMLMenuItemElement.h"
 
 #include "core/HTMLNames.h"
+#include "core/dom/ElementTraversal.h"
 #include "core/events/Event.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 inline HTMLMenuItemElement::HTMLMenuItemElement(Document& document)
     : HTMLElement(HTMLNames::menuitemTag, document)
 {
 }
 
 void HTMLMenuItemElement::defaultEventHandler(Event* event)
 {
     if (event->type() == EventTypeNames::click) {
         if (equalIgnoringCase(fastGetAttribute(typeAttr), "checkbox")) {
             if (fastHasAttribute(checkedAttr))
                 removeAttribute(checkedAttr);
             else
                 setAttribute(checkedAttr, "checked");
+        } else if (equalIgnoringCase(fastGetAttribute(typeAttr), "radio")) {
+            if (Element* parent = parentElement()) {
+                const AtomicString& group = fastGetAttribute(radiogroupAttr);
+                for (HTMLMenuItemElement& menuItem : Traversal<HTMLMenuItemElement>::childrenOf(*parent)) {
+                    if (!menuItem.fastHasAttribute(checkedAttr))
+                        continue;
+                    const AtomicString& groupAttr = menuItem.fastGetAttribute(radiogroupAttr);
+                    if (equalIgnoringNullity(groupAttr.impl(), group.impl()))
+                        menuItem.removeAttribute(checkedAttr);
+                }
+            }
+            setAttribute(checkedAttr, "checked");
         }
         event->setDefaultHandled();
     }
 }
 
 DEFINE_NODE_FACTORY(HTMLMenuItemElement)
 
 } // namespace blink