Reland "Change fallback font collection in HarfBuzzShaper"

Source/platform/fonts/shaping/HarfBuzzShaper.h

 /*
  * Copyright (C) 2012 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 45 matching lines @@
     static PassRefPtr<ShapeResult> create(unsigned numCharacters, TextDirection direction)
     {
         return adoptRef(new ShapeResult(numCharacters, direction));
     }
     ~ShapeResult();
 
     float width() { return m_width; }
     FloatRect bounds() { return m_glyphBoundingBox; }
     int offsetForPosition(float targetX);
     unsigned numCharacters() const { return m_numCharacters; }
-    const HashSet<const SimpleFontData*>* fallbackFonts() const
-    {
-        return &m_fallbackFonts;
-    }
+    void fallbackFonts(HashSet<const SimpleFontData*>*) const;
 
     static float fillGlyphBuffer(Vector<RefPtr<ShapeResult>>&,
         GlyphBuffer*, const TextRun&, unsigned from, unsigned to);
     static float fillGlyphBufferForTextEmphasis(Vector<RefPtr<ShapeResult>>&,
         GlyphBuffer*, const TextRun&, const GlyphData* emphasisData,
         unsigned from, unsigned to);
     static FloatRect selectionRect(Vector<RefPtr<ShapeResult>>&,
         TextDirection, float totalWidth, const FloatPoint&, int height,
         unsigned from, unsigned to);
 
@@ skipping 16 matching lines @@
     float fillGlyphBufferForRun(GlyphBuffer*, const RunInfo*,
         float initialAdvance, unsigned from, unsigned to, unsigned runOffset);
 
     float fillGlyphBufferForTextEmphasisRun(GlyphBuffer*, const RunInfo*,
         const TextRun&, const GlyphData*, float initialAdvance,
         unsigned from, unsigned to, unsigned runOffset);
 
     float m_width;
     FloatRect m_glyphBoundingBox;
     Vector<RunInfo*> m_runs;
-    HashSet<const SimpleFontData*> m_fallbackFonts;
+    const SimpleFontData* m_primaryFont;
 
     unsigned m_numCharacters;
     unsigned m_numGlyphs : 31;
 
     // Overall direction for the TextRun, dictates which order each individual
     // sub run (represented by RunInfo structs in the m_runs vector) can have a
     // different text direction.
     unsigned m_direction : 1;
 
     friend class HarfBuzzShaper;
 };
 
 class PLATFORM_EXPORT HarfBuzzShaper final : public Shaper {
 public:
-    HarfBuzzShaper(const Font*, const TextRun&,
-        HashSet<const SimpleFontData*>* fallbackFonts);
+    HarfBuzzShaper(const Font*, const TextRun&);
     PassRefPtr<ShapeResult> shapeResult();
     ~HarfBuzzShaper() { }
 
 private:
     struct HarfBuzzRun {
         const SimpleFontData* m_fontData;
         unsigned m_startIndex;
         size_t m_numCharacters;
         hb_direction_t m_direction;
         hb_script_t m_script;
@@ skipping 17 matching lines @@
     float m_letterSpacing; // Pixels to be added after each glyph.
     unsigned m_expansionOpportunityCount;
 
     Vector<hb_feature_t, 4> m_features;
     Vector<HarfBuzzRun, 16> m_harfBuzzRuns;
 };
 
 } // namespace blink
 
 #endif // HarfBuzzShaper_h