Oilpan: Allocate all EventTarget derived types on the manged heap.

Source/core/svg/SVGElementInstance.cpp

 /*
  * Copyright (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2011 Torch Mobile (Beijing) Co. Ltd. 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.
  *
@@ skipping 216 matching lines @@
 {
     visitor->trace(m_parentInstance);
     visitor->trace(m_correspondingUseElement);
     visitor->trace(m_directUseElement);
     visitor->trace(m_element);
     visitor->trace(m_shadowTreeElement);
     visitor->trace(m_previousSibling);
     visitor->trace(m_nextSibling);
     visitor->trace(m_firstChild);
     visitor->trace(m_lastChild);
+    EventTarget::trace(visitor);
 }
 
 }