Use glyph-ids for lookups of SVG font kerning-pairs

Source/platform/fonts/WidthIterator.h

 /*
  * Copyright (C) 2003, 2006, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Holger Hans Peter Freyther
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 37 matching lines @@
 
     float maxGlyphBoundingBoxY() const { ASSERT(m_accountForGlyphBounds); return m_maxGlyphBoundingBoxY; }
     float minGlyphBoundingBoxY() const { ASSERT(m_accountForGlyphBounds); return m_minGlyphBoundingBoxY; }
     float firstGlyphOverflow() const { ASSERT(m_accountForGlyphBounds); return m_firstGlyphOverflow; }
     float lastGlyphOverflow() const { ASSERT(m_accountForGlyphBounds); return m_lastGlyphOverflow; }
 
     const TextRun& run() const { return m_run; }
     float runWidthSoFar() const { return m_runWidthSoFar; }
 
 #if ENABLE(SVG_FONTS)
-    String lastGlyphName() const { return m_lastGlyphName; }
-    void setLastGlyphName(const String& name) { m_lastGlyphName = name; }
     Vector<SVGGlyph::ArabicForm>& arabicForms() { return m_arabicForms; }
 #endif
 
     static bool supportsTypesettingFeatures(const Font& font)
     {
 
         return !font.fontDescription().typesettingFeatures();
     }
 
     const Font* m_font;
 
     const TextRun& m_run;
 
     unsigned m_currentCharacter;
     float m_runWidthSoFar;
     float m_expansion;
     float m_expansionPerOpportunity;
     bool m_isAfterExpansion;
     float m_finalRoundingWidth;
 
 #if ENABLE(SVG_FONTS)
-    String m_lastGlyphName;
     Vector<SVGGlyph::ArabicForm> m_arabicForms;
 #endif
 
 private:
     GlyphData glyphDataForCharacter(UChar32, bool mirror, int currentCharacter, unsigned& advanceLength);
     template <typename TextIterator>
     inline unsigned advanceInternal(TextIterator&, GlyphBuffer*);
 
     bool shouldApplyFontTransforms() const { return m_run.length() > 1 && (m_typesettingFeatures & (Kerning | Ligatures)); }
 
     TypesettingFeatures m_typesettingFeatures;
     HashSet<const SimpleFontData*>* m_fallbackFonts;
     bool m_accountForGlyphBounds;
     float m_maxGlyphBoundingBoxY;
     float m_minGlyphBoundingBoxY;
     float m_firstGlyphOverflow;
     float m_lastGlyphOverflow;
     bool m_forTextEmphasis;
 };
 
 }
 
 #endif