Offset-only GlyphBuffer

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 111 matching lines @@
     int determineWordBreakSpacing();
     // setPadding sets a number of pixels to be distributed across the TextRun.
     // WebKit uses this to justify text.
     void setPadding(int);
 
     void setFontFeatures();
 
     bool createHarfBuzzRuns();
     bool shapeHarfBuzzRuns();
     bool fillGlyphBuffer(GlyphBuffer*);
-    void fillGlyphBufferFromHarfBuzzRun(GlyphBuffer*, HarfBuzzRun*, float& carryAdvance);
-    void fillGlyphBufferForTextEmphasis(GlyphBuffer*, HarfBuzzRun* currentRun);
+    float fillGlyphBufferFromHarfBuzzRun(GlyphBuffer*, HarfBuzzRun*, float initialAdvance);
+    float fillGlyphBufferForTextEmphasis(GlyphBuffer*, HarfBuzzRun*, float initialAdvance);
     void setGlyphPositionsForHarfBuzzRun(HarfBuzzRun*, hb_buffer_t*);
     void addHarfBuzzRun(unsigned startCharacter, unsigned endCharacter, const SimpleFontData*, UScriptCode);
 
     const Font* m_font;
     OwnPtr<UChar[]> m_normalizedBuffer;
     unsigned m_normalizedBufferLength;
     const TextRun& m_run;
 
     float m_wordSpacingAdjustment; // Delta adjustment (pixels) for each word break.
     float m_padding; // Pixels to be distributed over the line at word breaks.
@@ skipping 12 matching lines @@
     float m_totalWidth;
     FloatBoxExtent m_glyphBoundingBox;
     HashSet<const SimpleFontData*>* m_fallbackFonts;
 
     friend struct CachedShapingResults;
 };
 
 } // namespace blink
 
 #endif // HarfBuzzShaper_h