Oilpan: Replace most of RefPtrs for Event objects with oilpan's transition types

Source/core/css/FontFaceSet.cpp

Index: Source/core/css/FontFaceSet.cpp
diff --git a/Source/core/css/FontFaceSet.cpp b/Source/core/css/FontFaceSet.cpp
index f147f914371fc2081e39ee5026706fd81b59fbc7..822098a205cc56dc101432ae82fd6f82e62b540e 100644
--- a/Source/core/css/FontFaceSet.cpp
+++ b/Source/core/css/FontFaceSet.cpp
@@ -407,8 +407,8 @@ void FontFaceSet::fireDoneEventIfPossible()
         return;
 
     if (hasLoadedFonts()) {
-        RefPtr<CSSFontFaceLoadEvent> doneEvent;
-        RefPtr<CSSFontFaceLoadEvent> errorEvent;
+        RefPtrWillBeRawPtr<CSSFontFaceLoadEvent> doneEvent;
+        RefPtrWillBeRawPtr<CSSFontFaceLoadEvent> errorEvent;
         doneEvent = CSSFontFaceLoadEvent::createForFontFaces(EventTypeNames::loadingdone, m_loadedFonts);
         m_loadedFonts.clear();
         if (!m_failedFonts.isEmpty()) {