Hollow out more of the tracing system in oilpan

sky/engine/core/css/FontFaceSet.h

 /*
  * Copyright (C) 2013 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 86 matching lines @@
     // ActiveDOMObject
     virtual void suspend() override;
     virtual void resume() override;
     virtual void stop() override;
 
     static PassRefPtr<FontFaceSet> from(Document&);
     static void didLayout(Document&);
 
     void addFontFacesToFontFaceCache(FontFaceCache*, CSSFontSelector*);
 
-#if ENABLE(OILPAN)
-    virtual void trace(Visitor*) override;
-#endif
-
 private:
     static PassRefPtr<FontFaceSet> create(Document& document)
     {
         return adoptRef(new FontFaceSet(document));
     }
 
     class FontLoadHistogram {
     public:
         enum Status { NoWebFonts, HadBlankText, DidNotHaveBlankText, Reported };
         FontLoadHistogram() : m_status(NoWebFonts), m_count(0), m_recorded(false) { }
@@ skipping 31 matching lines @@
     ListHashSet<RefPtr<FontFace> > m_nonCSSConnectedFaces;
 
     AsyncMethodRunner<FontFaceSet> m_asyncRunner;
 
     FontLoadHistogram m_histogram;
 };
 
 } // namespace blink
 
 #endif // FontFaceSet_h