Implement contextmenu attribute with basic support of <menu>

Source/core/page/CustomContextMenuProvider.cpp

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/page/CustomContextMenuProvider.h"
+
+#include "core/dom/Document.h"
+#include "core/events/EventDispatcher.h"
+#include "core/events/MouseEvent.h"
+#include "core/html/HTMLMenuElement.h"
+#include "core/html/HTMLMenuItemElement.h"
+#include "core/page/ContextMenuController.h"
+#include "core/page/Page.h"
+#include "platform/ContextMenu.h"
+
+namespace blink {
+
+CustomContextMenuProvider::CustomContextMenuProvider(PassRefPtr<Document> document, const Vector<ContextMenuItem>& items)
+    : m_document(document)
+    , m_items(items)
+{
+}
+
+CustomContextMenuProvider::~CustomContextMenuProvider()
+{
+}
+
+void CustomContextMenuProvider::populateContextMenu(ContextMenu* menu)
+{
+    for (size_t i = 0; i < m_items.size(); ++i)
+        menu->appendItem(m_items[i]);
+}
+
+void CustomContextMenuProvider::contextMenuItemSelected(const ContextMenuItem* item)
+{
+    if (HTMLElement* element = m_document->page()->contextMenuController().menuItemAt(item->action())) {
+        RefPtrWillBeRawPtr<SimulatedMouseEvent> click = SimulatedMouseEvent::create(EventTypeNames::click, m_document->domWindow(), Event::create());
+        click->setRelatedTarget(m_document->page()->contextMenuController().subjectElement());
+        element->dispatchEvent(click.release());
+    }
+}
+
+} // namespace blink