Add <menuitem>, new HTMLMenuElement IDL attributes.

Source/core/html/parser/HTMLTreeBuilder.cpp

Index: Source/core/html/parser/HTMLTreeBuilder.cpp
diff --git a/Source/core/html/parser/HTMLTreeBuilder.cpp b/Source/core/html/parser/HTMLTreeBuilder.cpp
index 69603bbb61ff75eb38cf3113a6588d1924c869bb..a79d14de285309ccdc727ae894e169da10b32c47 100644
--- a/Source/core/html/parser/HTMLTreeBuilder.cpp
+++ b/Source/core/html/parser/HTMLTreeBuilder.cpp
@@ -800,7 +800,8 @@ void HTMLTreeBuilder::processStartTagForInBody(AtomicHTMLToken* token)
             m_framesetOk = false;
         return;
     }
-    if (token->name() == paramTag
+    if ((RuntimeEnabledFeatures::contextMenuEnabled() && token->name() == menuitemTag)

[tkent, 2014/08/11 10:23:01]

Could you explain what part of the specification brings this change and what
behavior is changed?

[pals, 2014/08/11 11:27:20]

Specification:
http://www.whatwg.org/specs/web-apps/current-work/multipage/syntax.html#ackno...
"When an end tag token is emitted with its self-closing flag set, that is a
parse error."
<menuitem> has no end tag, its a self closing tag, and it should not contain any
inner node.

[tkent, 2014/08/11 13:36:57]

Unfortunately the URL is broken.  Please mention it in the CL description.

[pals, 2014/08/11 14:07:08]

sorry, I copied the text of my previous comment which got the urls ellipsisized.
Anyway, I updated the CL description. 

+        || token->name() == paramTag
         || token->name() == sourceTag
         || token->name() == trackTag) {
         m_tree.insertSelfClosingHTMLElement(token);