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 7a674d82c43db58abe78202aadc0812954ee6a51..55305e7cc13eb310cd612fe51786c4fe70d6a851 100644
--- a/Source/platform/fonts/shaping/HarfBuzzShaper.h
+++ b/Source/platform/fonts/shaping/HarfBuzzShaper.h
@@ -119,8 +119,12 @@ 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);
@@ -129,9 +133,6 @@ private:
     float adjustSpacing(HarfBuzzRun*, size_t glyphIndex, unsigned currentCharacterIndex, HarfBuzzRun* previousRun, float& offsetX, float& totalAdvance);
     void addHarfBuzzRun(unsigned startCharacter, unsigned endCharacter, const SimpleFontData*, UScriptCode);
 
-    OwnPtr<UChar[]> m_normalizedBuffer;
-    unsigned m_normalizedBufferLength;
-
     float m_wordSpacingAdjustment; // Delta adjustment (pixels) for each word break.
     float m_letterSpacing; // Pixels to be added after each glyph.
     unsigned m_expansionOpportunityCount;