Virtualize EventDispatchMediator creation and cleanup calling.

Source/core/events/PointerEvent.h

 // Copyright 2015 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 PointerEvent_h
 #define PointerEvent_h
 
 #include "core/events/MouseEvent.h"
 #include "core/events/PointerEventInit.h"
 
@@ skipping 18 matching lines @@
     double height() const { return m_height; }
     float pressure() const { return m_pressure; }
     long tiltX() const { return m_tiltX; }
     long tiltY() const { return m_tiltY; }
     const String& pointerType() const { return m_pointerType; }
     bool isPrimary() const { return m_isPrimary; }
 
     bool isMouseEvent() const override;
     bool isPointerEvent() const override;
 
+    PassRefPtrWillBeRawPtr<EventDispatchMediator> createMediator() override;
+
     DECLARE_VIRTUAL_TRACE();
 
 private:
     PointerEvent();
     PointerEvent(const AtomicString&, const PointerEventInit&);
 
     long m_pointerId;
     double m_width;
     double m_height;
     float m_pressure;
@@ skipping 12 matching lines @@
     explicit PointerEventDispatchMediator(PassRefPtrWillBeRawPtr<PointerEvent>);
     PointerEvent& event() const;
     bool dispatchEvent(EventDispatcher&) const override;
 };
 
 DEFINE_EVENT_TYPE_CASTS(PointerEvent);
 
 } // namespace blink
 
 #endif // PointerEvent_h