Implement contextmenu attribute with basic support of <menu>

Source/core/html/HTMLMenuElement.h

Index: Source/core/html/HTMLMenuElement.h
diff --git a/Source/core/html/HTMLMenuElement.h b/Source/core/html/HTMLMenuElement.h
index 07350e282252796156e4210a88b80d0c22e20cd1..5aac4378ef32c6cc225c498584e1074adcba8255 100644
--- a/Source/core/html/HTMLMenuElement.h
+++ b/Source/core/html/HTMLMenuElement.h
@@ -23,16 +23,30 @@
 #ifndef HTMLMenuElement_h
 #define HTMLMenuElement_h
 
+#include "core/html/CustomContextMenuProvider.h"
 #include "core/html/HTMLElement.h"
+#include "core/page/ContextMenuProvider.h"
+#include "platform/ContextMenu.h"
+#include "platform/ContextMenuItem.h"
 
 namespace WebCore {
 
+class HTMLMenuElement;
+class CustomContextMenuProvider;
+
 class HTMLMenuElement FINAL : public HTMLElement {
 public:
     static PassRefPtrWillBeRawPtr<HTMLMenuElement> create(Document&);
 
+    void buildCustomProvider();

[esprehn, 2014/06/06 22:30:42]

This method doesn't exist.

[pals, 2014/06/10 10:42:39]

Done. Removed.

+    CustomContextMenuProvider* customProvider() { return m_menuProvider.get(); }
+    CustomContextMenuProvider& ensureCustomProvider();
+    void populateContextMenuItems(HTMLMenuElement*, ContextMenu&);
+    HTMLElement* selectedMenuItem(unsigned menuId);

[esprehn, 2014/06/06 22:30:42]

I'm not sure I understand the purpose of this.

[pals, 2014/06/10 10:42:39]

I am calling this method from 
Source/core/html/CustomContextMenuProvider.cpp to get the corresponding
MenuitemElement for the selected context menu item by the user. Renamed the
function as menuItemAt(unsigned menuId) as name was confusing.

 private:
     explicit HTMLMenuElement(Document&);
+    RefPtr<CustomContextMenuProvider> m_menuProvider;
+    Vector<HTMLElement*> m_menuItems;
 };
 
 } //namespace