Optimize complex text shaping

Source/platform/fonts/shaping/HarfBuzzShaper.h

Index: Source/platform/fonts/shaping/HarfBuzzShaper.h
diff --git a/Source/platform/fonts/shaping/HarfBuzzShaper.h b/Source/platform/fonts/shaping/HarfBuzzShaper.h
index ab34cee996655cdabf11b085acb0813e824b13fe..8fcac47e9238abe04c7b15b51da7b896f0c93248 100644
--- a/Source/platform/fonts/shaping/HarfBuzzShaper.h
+++ b/Source/platform/fonts/shaping/HarfBuzzShaper.h
@@ -123,8 +123,12 @@ private:
 
     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);
@@ -134,8 +138,6 @@ private:
     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.