Skip redundant fonts returned by FontFallbackIterator

third_party/WebKit/Source/platform/fonts/FontDataForRangeSet.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 40 matching lines @@
         UnicodeRange range(from, to);
         Vector<UnicodeRange> rangeVector;
         rangeVector.append(range);
         m_rangeSet = adoptRef(new UnicodeRangeSet(rangeVector));
     }
 
     FontDataForRangeSet(const FontDataForRangeSet& other);
 
     virtual ~FontDataForRangeSet() { };
 
-    bool contains(UChar32 testChar) const { return m_rangeSet->contains(testChar); }
-    bool isEntireRange() const { return m_rangeSet->isEntireRange(); }
+    bool contains(UChar32 testChar) const { return !m_rangeSet || m_rangeSet->contains(testChar); }
+    bool isEntireRange() const { return !m_rangeSet || m_rangeSet->isEntireRange(); }
     UnicodeRangeSet* ranges() const { return m_rangeSet.get(); }
     bool hasFontData() const { return m_fontData.get(); }
     const SimpleFontData* fontData() const { return m_fontData.get(); }
 
 protected:
     RefPtr<SimpleFontData> m_fontData;
     RefPtr<UnicodeRangeSet> m_rangeSet;
 };
 
 class PLATFORM_EXPORT FontDataForRangeSetFromCache : public FontDataForRangeSet {
 public:
     explicit FontDataForRangeSetFromCache(PassRefPtr<SimpleFontData> fontData,
         PassRefPtr<UnicodeRangeSet> rangeSet = nullptr)
         : FontDataForRangeSet(fontData, rangeSet)
     {
     }
     virtual ~FontDataForRangeSetFromCache();
 };
 
 } // namespace blink
 
 #endif