Implement checked attribute for menuitem.

Source/core/html/HTMLMenuItemElement.cpp

Index: Source/core/html/HTMLMenuItemElement.cpp
diff --git a/Source/core/html/HTMLMenuItemElement.cpp b/Source/core/html/HTMLMenuItemElement.cpp
index e0774e7552ac538ebad2d36115441908ff55c6e5..79d6759ffca96ab5b80873e38fc0bade7e363d41 100644
--- a/Source/core/html/HTMLMenuItemElement.cpp
+++ b/Source/core/html/HTMLMenuItemElement.cpp
@@ -6,14 +6,30 @@
 #include "core/html/HTMLMenuItemElement.h"
 
 #include "core/HTMLNames.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");
+        }
+        event->setDefaultHandled();
+    }
+}
+
 DEFINE_NODE_FACTORY(HTMLMenuItemElement)
 
 } // namespace blink