UMA histograms to measure whether / how long blank text is rendered for loading web fonts

Source/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 93 matching lines @@
 private:
     typedef RefCountedSupplement<Document, FontFaceSet> SupplementType;
 
     static PassRefPtr<FontFaceSet> create(Document& document)
     {
         return adoptRef<FontFaceSet>(new FontFaceSet(document));
     }
 
     class FontLoadHistogram {
     public:
-        FontLoadHistogram() : m_count(0), m_recorded(false) { }
+        enum Status { NoWebFonts, HadBlankText, DidNotHaveBlankText, Reported };
+        FontLoadHistogram() : m_status(NoWebFonts), m_count(0), m_recorded(false) { }
         void incrementCount() { m_count++; }
+        void updateStatus(FontFace*);
         void record();
 
     private:
+        Status m_status;
         int m_count;
         bool m_recorded;
     };
 
     FontFaceSet(Document&);
 
     bool hasLoadedFonts() const { return !m_loadedFonts.isEmpty() || !m_failedFonts.isEmpty(); }
 
     bool inActiveDocumentContext() const;
     void forEachInternal(PassOwnPtr<FontFaceSetForEachCallback>, ScriptValue* thisArg) const;
@@ skipping 15 matching lines @@
     ListHashSet<RefPtr<FontFace> > m_nonCSSConnectedFaces;
 
     AsyncMethodRunner<FontFaceSet> m_asyncRunner;
 
     FontLoadHistogram m_histogram;
 };
 
 } // namespace WebCore
 
 #endif // FontFaceSet_h