Virtualize EventDispatchMediator creation and cleanup calling.

Source/core/events/Event.cpp

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "core/events/Event.h"
 
 #include "core/dom/StaticNodeList.h"
+#include "core/events/EventDispatchMediator.h"
 #include "core/events/EventTarget.h"
 #include "core/frame/OriginsUsingFeatures.h"
 #include "core/frame/UseCounter.h"
 #include "core/svg/SVGElement.h"
 #include "wtf/CurrentTime.h"
 
 namespace blink {
 
 Event::Event()
     : Event("", false, false)
@@ skipping 193 matching lines @@
     }
 
     // Returns [window] for events that are directly dispatched to the window object;
     // e.g., window.load, pageshow, etc.
     if (LocalDOMWindow* window = m_currentTarget->toDOMWindow())
         return WillBeHeapVector<RefPtrWillBeMember<EventTarget>>(1, window);
 
     return WillBeHeapVector<RefPtrWillBeMember<EventTarget>>();
 }
 
+PassRefPtrWillBeRawPtr<EventDispatchMediator> Event::createMediator()
+{
+    return EventDispatchMediator::create(this);
+}
+
 EventTarget* Event::currentTarget() const
 {
     if (!m_currentTarget)
         return 0;
     Node* node = m_currentTarget->toNode();
     if (node && node->isSVGElement()) {
         if (SVGElement* svgElement = toSVGElement(node)->correspondingElement())
             return svgElement;
     }
     return m_currentTarget.get();
 }
 
 DEFINE_TRACE(Event)
 {
     visitor->trace(m_currentTarget);
     visitor->trace(m_target);
     visitor->trace(m_underlyingEvent);
     visitor->trace(m_eventPath);
 }
 
 } // namespace blink