Oilpan: Remove support for tracing off-heap HashSets.

Source/core/svg/SVGElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
  *
  * 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
@@ skipping 1142 matching lines @@
     for (SVGElementSet::iterator it = outgoingReferences.begin(), itEnd = outgoingReferences.end(); it != itEnd; ++it) {
         SVGElement* targetElement = *it;
         ASSERT(targetElement->hasSVGRareData());
         targetElement->ensureSVGRareData()->incomingReferences().remove(this);
     }
     outgoingReferences.clear();
 }
 
 void SVGElement::trace(Visitor* visitor)
 {
+#if ENABLE(OILPAN)
     visitor->trace(m_elementsWithRelativeLengths);
     visitor->trace(m_SVGRareData);
+#endif
     Element::trace(visitor);
 }
 
 const AtomicString& SVGElement::eventParameterName()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, evtString, ("evt", AtomicString::ConstructFromLiteral));
     return evtString;
 }
 
 }