Oilpan: Remove support for tracing off-heap HashSets.

Source/core/html/forms/RadioButtonGroupScope.cpp

 /*
  * Copyright (C) 2007, 2008, 2009 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
@@ skipping 157 matching lines @@
     }
 }
 
 bool RadioButtonGroup::contains(HTMLInputElement* button) const
 {
     return m_members.contains(button);
 }
 
 void RadioButtonGroup::trace(Visitor* visitor)
 {
+#if ENABLE(OILPAN)
     visitor->trace(m_members);
     visitor->trace(m_checkedButton);
+#endif
 }
 
 // ----------------------------------------------------------------
 
 // Explicity define empty constructor and destructor in order to prevent the
 // compiler from generating them as inlines. So we don't need to to define
 // RadioButtonGroup in the header.
 RadioButtonGroupScope::RadioButtonGroupScope()
 {
 }
@@ skipping 83 matching lines @@
 }
 
 void RadioButtonGroupScope::trace(Visitor* visitor)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_nameToGroupMap);
 #endif
 }
 
 } // namespace