Remove tons of OILPAN.

sky/engine/core/html/ClassList.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 37 matching lines @@
 #if !ENABLE(OILPAN)
     virtual void ref() override;
     virtual void deref() override;
 #endif
 
     virtual unsigned length() const override;
     virtual const AtomicString item(unsigned index) const override;
 
     virtual Element* element() override { return m_element; }
 
-    virtual void trace(Visitor*) override;
-
 private:
     explicit ClassList(Element*);
 
     virtual bool containsInternal(const AtomicString&) const override;
 
     const SpaceSplitString& classNames() const;
 
     virtual const AtomicString& value() const override { return m_element->getAttribute(HTMLNames::classAttr); }
     virtual void setValue(const AtomicString& value) override { m_element->setAttribute(HTMLNames::classAttr, value); }
 
     RawPtr<Element> m_element;
 };
 
 } // namespace blink
 
 #endif // ClassList_h