Optimize complex text shaping

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 105 matching lines @@
         float m_width;
     };
 
     float nextExpansionPerOpportunity();
     // setPadding sets a number of pixels to be distributed across the TextRun.
     // WebKit uses this to justify text.
     void setExpansion(float);
 
     void setFontFeatures();
 
+    template<typename CharType>
+    bool shapeInternal(GlyphBuffer*);
+    template<typename CharType>
     bool createHarfBuzzRuns();
     bool createHarfBuzzRunsForSingleCharacter();
+    template<typename CharType>
     bool shapeHarfBuzzRuns();
     bool fillGlyphBuffer(GlyphBuffer*);
     float fillGlyphBufferFromHarfBuzzRun(GlyphBuffer*, HarfBuzzRun*, float initialAdvance);
     float fillGlyphBufferForTextEmphasis(GlyphBuffer*, HarfBuzzRun*, float initialAdvance);
     void setGlyphPositionsForHarfBuzzRun(HarfBuzzRun*, hb_buffer_t*, HarfBuzzRun* previousRun);
     float adjustSpacing(HarfBuzzRun*, size_t glyphIndex, unsigned currentCharacterIndex, HarfBuzzRun* previousRun, float& offsetX, float& totalAdvance);
     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_expansion; // Pixels to be distributed over the line at word breaks.
     float m_letterSpacing; // Pixels to be added after each glyph.
     float m_expansionPerOpportunity; // Pixels to be added to each expansion opportunity.
     unsigned m_expansionOpportunityCount;
     bool m_isAfterExpansion;
 
     Vector<hb_feature_t, 4> m_features;
     Vector<OwnPtr<HarfBuzzRun>, 16> m_harfBuzzRuns;
 
     int m_fromIndex;
     int m_toIndex;
 
     ForTextEmphasisOrNot m_forTextEmphasis;
 
     float m_totalWidth;
     FloatRect* m_glyphBoundingBox;
     HashSet<const SimpleFontData*>* m_fallbackFonts;
 
     friend struct CachedShapingResults;
 };
 
 } // namespace blink
 
 #endif // HarfBuzzShaper_h