Implement contextmenu attribute with basic support of <menu>

Source/core/events/RelatedEvent.h

Index: Source/core/events/RelatedEvent.h
diff --git a/Source/core/events/RelatedEvent.h b/Source/core/events/RelatedEvent.h
new file mode 100644
index 0000000000000000000000000000000000000000..ff31cec1c04e2eedd598908ba8bb0ccd851f6519
--- /dev/null
+++ b/Source/core/events/RelatedEvent.h
@@ -0,0 +1,49 @@
+// 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.
+
+#ifndef RelatedEvent_h
+#define RelatedEvent_h
+
+#include "core/events/Event.h"
+
+namespace blink {
+
+struct RelatedEventInit : public EventInit {
+    RelatedEventInit();
+    RefPtrWillBeMember<EventTarget> relatedTarget;
+};
+
+class RelatedEvent FINAL : public Event {
+public:
+    static PassRefPtrWillBeRawPtr<RelatedEvent> create()
+    {

[tkent, 2014/07/25 04:42:37]

The function implementation should be moved to RelatedEvent.cpp for consistency
with other |create| functions.

[pals, 2014/07/30 09:47:42]

Done.

+        return adoptRef(new RelatedEvent);

[tkent, 2014/07/25 04:42:37]

adoptRef -> adoptRefWillBeNoop

[pals, 2014/07/30 09:47:42]

Done.

+    }
+
+    static PassRefPtrWillBeRawPtr<RelatedEvent> create(const AtomicString& eventType);
+    static PassRefPtrWillBeRawPtr<RelatedEvent> create(const AtomicString& eventType, const RelatedEventInit&);
+
+    virtual ~RelatedEvent();
+
+    EventTarget* relatedTarget() const { return m_relatedTarget.get(); }
+    void setRelatedTarget(PassRefPtrWillBeRawPtr<EventTarget> relatedTarget) { m_relatedTarget = relatedTarget; }
+
+
+    virtual const AtomicString& interfaceName() const OVERRIDE { return EventNames::RelatedEvent; }
+    virtual bool isRelatedEvent() const OVERRIDE { return true; }
+
+protected:

[tkent, 2014/07/25 04:42:37]

This should be private.

[pals, 2014/07/30 09:47:42]

Done.

+    RelatedEvent();
+    explicit RelatedEvent(const AtomicString& type);
+    RelatedEvent(const AtomicString& type, const RelatedEventInit&);
+
+private:
+    RefPtrWillBeMember<EventTarget> m_relatedTarget;

[tkent, 2014/07/25 04:42:37]

Because this class has Member<>, we need to have trace() function.  Please refer
to FocusEvent.

[pals, 2014/07/30 09:47:42]

Done.

+};
+
+DEFINE_EVENT_TYPE_CASTS(RelatedEvent);
+
+} // namespace blink
+
+#endif // RelatedEvent_h