Invalidation not taking glyph bounds into account on HarfBuzz path

Source/platform/fonts/harfbuzz/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 43 matching lines @@
 
     HarfBuzzShaper(const Font*, const TextRun&, ForTextEmphasisOrNot = NotForTextEmphasis);
 
     void setDrawRange(int from, int to);
     bool shape(GlyphBuffer* = 0);
     FloatPoint adjustStartPoint(const FloatPoint&);
     float totalWidth() { return m_totalWidth; }
     int offsetForPosition(float targetX);
     FloatRect selectionRect(const FloatPoint&, int height, int from, int to);
 
+    float minGlyphBoundingBoxX() const { return m_minGlyphBoundingBoxX; }
+    float maxGlyphBoundingBoxX() const { return m_maxGlyphBoundingBoxX; }
+    float minGlyphBoundingBoxY() const { return m_minGlyphBoundingBoxY; }
+    float maxGlyphBoundingBoxY() const { return m_maxGlyphBoundingBoxY; }
+
 private:
     class HarfBuzzRun {
     public:
         HarfBuzzRun(const HarfBuzzRun&);
         ~HarfBuzzRun();
 
         static PassOwnPtr<HarfBuzzRun> create(const SimpleFontData* fontData, unsigned startIndex, unsigned numCharacters, TextDirection direction, hb_script_t script)
         {
             return adoptPtr(new HarfBuzzRun(fontData, startIndex, numCharacters, direction, script));
         }
@@ skipping 77 matching lines @@
     Vector<OwnPtr<HarfBuzzRun>, 16> m_harfBuzzRuns;
 
     FloatPoint m_startOffset;
 
     int m_fromIndex;
     int m_toIndex;
 
     ForTextEmphasisOrNot m_forTextEmphasis;
 
     float m_totalWidth;
+    float m_minGlyphBoundingBoxX;
+    float m_maxGlyphBoundingBoxX;
+    float m_minGlyphBoundingBoxY;
+    float m_maxGlyphBoundingBoxY;
 
     friend struct CachedShapingResults;
 };
 
 } // namespace WebCore
 
 #endif // HarfBuzzShaper_h