Implement contextmenu attribute with basic support of <menu>

Source/core/html/HTMLMenuElement.cpp

Index: Source/core/html/HTMLMenuElement.cpp
diff --git a/Source/core/html/HTMLMenuElement.cpp b/Source/core/html/HTMLMenuElement.cpp
index 36a44dc57318e6d07d22f415390cf8273c6f7bea..ddba1a0fe5355c974029775b7a6afbbe8de3276c 100644
--- a/Source/core/html/HTMLMenuElement.cpp
+++ b/Source/core/html/HTMLMenuElement.cpp
@@ -23,7 +23,11 @@
 #include "config.h"
 #include "core/html/HTMLMenuElement.h"
 
-#include "core/HTMLNames.h"
+#include "core/dom/ElementTraversal.h"
+#include "core/events/RelatedEvent.h"
+#include "core/html/HTMLMenuItemElement.h"
+#include "core/page/ContextMenuController.h"
+#include "core/page/Page.h"
 
 namespace blink {
 
@@ -37,4 +41,50 @@ inline HTMLMenuElement::HTMLMenuElement(Document& document)
 
 DEFINE_NODE_FACTORY(HTMLMenuElement)
 
+CustomContextMenuProvider& HTMLMenuElement::ensureMenuProvider()
+{
+    if (!m_menuProvider) {
+        ContextMenu menu;
+        populateContextMenuItems(*this, menu);
+        m_menuProvider = CustomContextMenuProvider::create(this, menu.items());
+    }
+    return *m_menuProvider;
+}
+
+void HTMLMenuElement::populateContextMenuItems(const HTMLMenuElement& menu, ContextMenu& contextMenu)
+{
+    HTMLElement* nextElement = Traversal<HTMLElement>::firstWithin(menu);
+    while (nextElement) {
+        if (isHTMLMenuElement(*nextElement)) {
+            ContextMenu subMenu;
+            populateContextMenuItems(*toHTMLMenuElement(nextElement), subMenu);
+            contextMenu.appendItem(ContextMenuItem(SubmenuType, ContextMenuItemCustomTagNoAction, nextElement->fastGetAttribute(HTMLNames::labelAttr), &subMenu));

[Inactive, 2014/07/23 14:19:08]

HTMLNames:: are not needed in this file

[pals, 2014/07/24 10:49:26]

Done.

+            nextElement = Traversal<HTMLElement>::nextSibling(*nextElement);
+        } else if (isHTMLMenuItemElement(*nextElement)) {
+            m_menuItems.append(nextElement);

[Inactive, 2014/07/23 14:19:08]

Looks like m_menuItems can only HTMLMenuItemElements? If so, please use tighter
typing.

[pals, 2014/07/24 10:49:26]

hr element can also be menuItems. hr elements can be used as separators between
menu items. But, in that case we don't need to store hr element in the list. I
shall change Vector<HTMLElement*> to Vector<HTMLMenuItemElement*> 

+            contextMenu.appendItem(ContextMenuItem(ActionType, static_cast<ContextMenuAction>(ContextMenuItemBaseCustomTag + m_menuItems.size() - 1), nextElement->fastGetAttribute(HTMLNames::labelAttr)));
+            if (ContextMenuItemBaseCustomTag + m_menuItems.size() >= ContextMenuItemLastCustomTag)
+                break;
+            nextElement = Traversal<HTMLElement>::next(*nextElement, &menu);
+        }
+    }
+}
+
+void HTMLMenuElement::defaultEventHandler(Event* event)
+{
+    if (event->type() == EventTypeNames::show && event->isRelatedEvent()) {
+        m_subject = toHTMLElement(toRelatedEvent(event)->relatedTarget()->toNode());

[Inactive, 2014/07/23 14:19:08]

Is this cast safe?

[pals, 2014/07/24 10:49:26]

Yes. we are checking for isRelatedEvent() here and isHTMLElemnt() before setting
relatedTarget in ContextMenuController.cpp. 

+        ensureMenuProvider();
+        event->setDefaultHandled();
+    }
+}
+
+HTMLElement* HTMLMenuElement::menuItemAt(unsigned menuId)

[Inactive, 2014/07/23 14:19:08]

Could return a HTMLMenuItemElement*

[pals, 2014/07/24 10:49:26]

Done.

+{
+    if (menuId < ContextMenuItemBaseCustomTag || menuId > ContextMenuItemLastCustomTag)
+        return 0;
+    int itemNumber = menuId - ContextMenuItemBaseCustomTag;

[Inactive, 2014/07/23 14:19:08]

itemIndex ?
Also, can we reverse this?
1. Compute the index
2. Do the bounds check if (itemIndex < 0 || itemIndex >= m_menuItems.size())
return 0;

[pals, 2014/07/24 10:49:26]

Done.

+    return m_menuItems[itemNumber];
+}
+
 }