Use FontFallbackPriority Fonts in FontFallbackIterator

third_party/WebKit/Source/platform/fonts/FontDataRange.h

 /*
  * Copyright (C) 2008, 2009 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 44 matching lines @@
         : m_from(from)
         , m_to(to)
         , m_fontData(fontData)
     {
     }
 
     UChar32 from() const { return m_from; }
     UChar32 to() const { return m_to; }
     bool contains(UChar32 testChar) { return testChar >= m_from && testChar <= m_to; }
     bool isEntireRange() const { return !m_from && m_to >= kMaxCodepoint; }
+    bool isNull() const { return !fontData(); }

[eae, 2016/02/17 18:55:17]

hasData or isEmpty would be better names. isNull would indicate that the struct
itself is null.

     PassRefPtr<SimpleFontData> fontData() const { return m_fontData; }
 
 private:
     UChar32 m_from;
     UChar32 m_to;
     RefPtr<SimpleFontData> m_fontData;
 };
 
 } // namespace blink
 
 #endif