[oilpan] Rename visit to mark.

Source/core/css/CSSFontSelector.cpp

 /*
  * Copyright (C) 2007, 2008, 2011 Apple Inc. All rights reserved.
  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * 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
@@ skipping 610 matching lines @@
     // Ensure that if the request count reaches zero, the frame loader will know about it.
     m_cachedResourceLoader->loadDone(0);
     // New font loads may be triggered by layout after the document load is complete but before we have dispatched
     // didFinishLoading for the frame. Make sure the delegate is always dispatched by checking explicitly.
     if (m_document->frame())
         m_document->frame()->loader()->checkLoadComplete();
 }
 
 void CSSFontSelector::trace(Visitor* visitor)
 {
-    // FIXME(oilpan): visiting m_document creates a cycle through a persistent handle because document owns StyleResolver
-    // which hold CSSFontSelector via persistent handle. Once StyleResolver is moved to the heap we should start visiting
-    // m_document again.
-    // visitor->trace(m_document);
+    visitor->trace(m_document);
     visitor->trace(m_fontFaces);
     visitor->trace(m_locallyInstalledFontFaces);
     visitor->trace(m_fonts);
 }
 
 }