Implement contextmenu attribute with basic support of <menu>

Source/core/page/ContextMenuController.cpp

Index: Source/core/page/ContextMenuController.cpp
diff --git a/Source/core/page/ContextMenuController.cpp b/Source/core/page/ContextMenuController.cpp
index 9e97e69bafd3d7dd0439fc22ff6960a5bce5e70a..fb60426cd0d83b108d4084737d895fff02c835eb 100644
--- a/Source/core/page/ContextMenuController.cpp
+++ b/Source/core/page/ContextMenuController.cpp
@@ -28,10 +28,14 @@
 #include "core/page/ContextMenuController.h"
 
 #include "core/dom/Document.h"
+#include "core/dom/Node.h"
 #include "core/events/Event.h"
+#include "core/events/EventDispatchMediator.h"
+#include "core/events/EventDispatcher.h"
 #include "core/events/MouseEvent.h"
-#include "core/dom/Node.h"
+#include "core/events/RelatedEvent.h"
 #include "core/frame/LocalFrame.h"
+#include "core/html/HTMLMenuElement.h"
 #include "core/page/ContextMenuClient.h"
 #include "core/page/ContextMenuProvider.h"
 #include "core/page/EventHandler.h"
@@ -40,6 +44,8 @@
 
 namespace blink {
 
+using namespace HTMLNames;
+
 ContextMenuController::ContextMenuController(Page*, ContextMenuClient* client)
     : m_client(client)
 {
@@ -80,6 +86,17 @@ void ContextMenuController::handleContextMenuEvent(Event* event)
     if (!m_contextMenu)
         return;
 
+    Node* node = event->target()->toNode();
+    if (node && node->isHTMLElement() && RuntimeEnabledFeatures::menuElementEnabled()) {
+        const HTMLElement& element = toHTMLElement(*node);
+        if (RefPtrWillBeRawPtr<HTMLMenuElement> menuElement = element.menuElement()) {
+            RefPtr<RelatedEvent> relatedEvent = RelatedEvent::create(EventTypeNames::show);
+            relatedEvent->setRelatedTarget(node);
+            EventDispatcher::dispatchEvent(menuElement.get(), EventDispatchMediator::create(relatedEvent.release()));

[tkent, 2014/07/25 04:42:38]

Why don't you use menuElement->dispatchEvent(relatedEvent.release())?

Also, this even this event is cancelable, and we need to check the return value.

[pals, 2014/07/30 09:47:44]

Done.

+            m_menuProvider = menuElement->menuProvider();

[tkent, 2014/07/25 04:42:38]

We should construct menu items here, not in HTMLMenuElement::dispatchEvent.  The
current code is complex unnecessarily.

[pals, 2014/07/30 09:47:44]

Done.

+            m_menuProvider->populateContextMenu(m_contextMenu.get());
+        }
+    }
     showContextMenu(event);
 }