[Oilpan]: Move CSSFontSelectorClient to the oilpan heap using transition types.

Source/core/css/CSSFontSelectorClient.h

 /*
  * Copyright (C) 2014 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef CSSFontSelectorClient_h
 #define CSSFontSelectorClient_h
 
 namespace WebCore {
 
 class CSSFontSelector;
 
-class CSSFontSelectorClient {
+class CSSFontSelectorClient : public NoBaseWillBeGarbageCollectedFinalized<CSSFontSelectorClient> {
 public:
     virtual ~CSSFontSelectorClient() { }
 
     virtual void fontsNeedUpdate(CSSFontSelector*) = 0;
+
+    virtual void trace(Visitor*) = 0;
 };
 
 } // namespace WebCore
 
 #endif // CSSFontSelectorClient_h