Add ability to compute text intercepts to Font

third_party/WebKit/Source/platform/fonts/Font.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2010, 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
@@ skipping 83 matching lines @@
                     CustomFontNotReadyAction,
                     float deviceScaleFactor,
                     const SkPaint&) const;
   void drawEmphasisMarks(SkCanvas*,
                          const TextRunPaintInfo&,
                          const AtomicString& mark,
                          const FloatPoint&,
                          float deviceScaleFactor,
                          const SkPaint&) const;
 
+  struct TextIntercept {
+    float m_begin, m_end;
+  };
+
+  // Compute the text intercepts along the axis of the advance and write them
+  // into the specified Vector of TextIntercepts. The number of those is zero or
+  // a multiple of two, and is at most the number of glyphs * 2 in the TextRun
+  // part of TextRunPaintInfo. Specify bounds for the upper and lower extend of
+  // a line crossing through the text, parallel to the baseline.
+  // TODO(drott): crbug.com/655154 Fix this for
+  // upright in vertical.
+  void getTextIntercepts(const TextRunPaintInfo&,
+                         float deviceScaleFactor,
+                         const SkPaint&,
+                         const std::tuple<float, float>& bounds,
+                         Vector<TextIntercept>&) const;
+
   // Glyph bounds will be the minimum rect containing all glyph strokes, in
   // coordinates using (<text run x position>, <baseline position>) as the
   // origin.
   float width(const TextRun&,
               HashSet<const SimpleFontData*>* fallbackFonts = nullptr,
               FloatRect* glyphBounds = nullptr) const;
 
   int offsetForPosition(const TextRun&,
                         float position,
                         bool includePartialGlyphs) const;
@@ skipping 143 matching lines @@
   // advance an additional tab stop.
   if (distanceToTabStop < fontData.spaceWidth() / 2)
     distanceToTabStop += baseTabWidth;
 
   return distanceToTabStop;
 }
 
 }  // namespace blink
 
 #endif