Change Font::offsetForPositionForComplexText to use CachingWordShapeIterator

Source/platform/fonts/shaping/CachingWordShaper.cpp

 /*
  * Copyright (C) 2015 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 68 matching lines @@
         if (wordResult) {
             results->append(wordResult);
             totalWidth += wordResult->width();
             if (fallbackFonts)
                 wordResult->fallbackFonts(fallbackFonts);
         }
     }
     return totalWidth;
 }
 
+int CachingWordShaper::offsetForPosition(const Font* font, const TextRun& run, float targetX)
+{
+    Vector<RefPtr<ShapeResult>> results;
+    shapeResultsForRun(m_shapeCache.get(), font, run, nullptr, &results);
+
+    return ShapeResult::offsetForPosition(results, run, targetX);
+}
+
 float CachingWordShaper::fillGlyphBuffer(const Font* font, const TextRun& run,
     HashSet<const SimpleFontData*>* fallbackFonts,
     GlyphBuffer* glyphBuffer, unsigned from, unsigned to)
 {
     Vector<RefPtr<ShapeResult>> results;
     shapeResultsForRun(m_shapeCache.get(), font, run, fallbackFonts, &results);
 
     return ShapeResult::fillGlyphBuffer(results, glyphBuffer, run, from, to);
 }
 
@@ skipping 13 matching lines @@
 {
     Vector<RefPtr<ShapeResult>> results;
     float totalWidth = shapeResultsForRun(m_shapeCache.get(), font, run, nullptr,
         &results);
 
     return ShapeResult::selectionRect(results, run.direction(), totalWidth,
         point, height, from, to);
 }
 
 }; // namespace blink