[DO NOT COMMIT] Trace events for layout-based First Meaningful Paint detection

third_party/WebKit/Source/core/css/CSSFontFace.cpp

 /*
  * Copyright (C) 2007, 2008, 2011 Apple 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 58 matching lines @@
         } else {
             m_sources.removeFirst();
             load();
         }
     }
 
     if (m_segmentedFontFace)
         m_segmentedFontFace->fontFaceInvalidated();
 }
 
+bool CSSFontFace::isBlank() const
+{
+    return !m_sources.isEmpty() && m_sources.first()->isBlank();
+}
+
 void CSSFontFace::didBecomeVisibleFallback(RemoteFontFaceSource* source)
 {
     if (!isValid() || source != m_sources.first())
         return;
     if (m_segmentedFontFace)
         m_segmentedFontFace->fontFaceInvalidated();
 }
 
 PassRefPtr<SimpleFontData> CSSFontFace::getFontData(const FontDescription& fontDescription)
 {
@@ skipping 107 matching lines @@
 }
 
 DEFINE_TRACE(CSSFontFace)
 {
     visitor->trace(m_segmentedFontFace);
     visitor->trace(m_sources);
     visitor->trace(m_fontFace);
 }
 
 } // namespace blink