Implement contextmenu attribute with basic support of <menu>

Source/core/events/RelatedEvent.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/events/RelatedEvent.h"
+
+namespace WebCore {
+
+RelatedEventInit::RelatedEventInit()
+{
+}
+
+PassRefPtr<RelatedEvent> RelatedEvent::create(const AtomicString& type)
+{
+    return adoptRef(new RelatedEvent(type));
+}
+
+PassRefPtr<RelatedEvent> RelatedEvent::create(const AtomicString& type, const RelatedEventInit& initializer)
+{
+    return adoptRef(new RelatedEvent(type, initializer));
+}
+
+RelatedEvent::RelatedEvent()
+{
+    ScriptWrappable::init(this);
+}
+
+RelatedEvent::RelatedEvent(const AtomicString& eventType)
+    : Event(eventType, true, true)
+{
+    ScriptWrappable::init(this);
+}
+
+RelatedEvent::RelatedEvent(const AtomicString& eventType, const RelatedEventInit& initializer)
+    : Event(eventType, initializer)
+{
+    ScriptWrappable::init(this);
+}
+
+} // namespace WebCore