Add ShapeResult::positionForOffset method

third_party/WebKit/Source/platform/fonts/shaping/ShapeResult.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 57 matching lines @@
   unsigned numCharacters() const { return m_numCharacters; }
   void fallbackFonts(HashSet<const SimpleFontData*>*) const;
   bool rtl() const {
     return static_cast<TextDirection>(m_direction) == TextDirection::kRtl;
   }
   bool hasVerticalOffsets() const { return m_hasVerticalOffsets; }
 
   // For memory reporting.
   size_t byteSize() const;
 
-  int offsetForPosition(float targetX, bool includePartialGlyphs) const;
+  unsigned offsetForPosition(float targetX, bool includePartialGlyphs) const;
+  float positionForOffset(unsigned offset) const;
 
   PassRefPtr<ShapeResult> applySpacingToCopy(ShapeResultSpacing&,
                                              const TextRun&) const;
 
  protected:
   struct RunInfo;
 
   ShapeResult(const Font*, unsigned numCharacters, TextDirection);
   ShapeResult(const ShapeResult&);
 
@@ skipping 23 matching lines @@
   // Tracks whether any runs contain glyphs with a y-offset != 0.
   unsigned m_hasVerticalOffsets : 1;
 
   friend class HarfBuzzShaper;
   friend class ShapeResultBuffer;
 };
 
 }  // namespace blink
 
 #endif  // ShapeResult_h