Force glyph overflow calculation

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 58 matching lines @@
         , bottom(0)
         , computeBounds(false)
     {
     }
 
     bool isZero() const
     {
         return !left && !right && !top && !bottom;
     }
 
+    // If computeBounds, top and bottom are the maximum heights of the glyphs above and below the baseline, respectively.
+    // Otherwise they are the amounts of glyph overflows exceeding the font metrics' ascent and descent, respectively.
+    // Left and right are the amounts of glyph overflows exceeding the left and right edge of normal layout boundary, respectively.
+    // All fields are in absolute number of pixels rounded up to the nearest integer.
     int left;
     int right;
     int top;
     int bottom;
     bool computeBounds;
 };
 
 class PLATFORM_EXPORT Font {
 public:
     Font();
@@ skipping 43 matching lines @@
     float buildGlyphBuffer(const TextRunPaintInfo&, GlyphBuffer&, const GlyphData* emphasisData = nullptr) const;
     PassTextBlobPtr buildTextBlob(const GlyphBuffer&) const;
     void paintGlyphs(SkCanvas*, const SkPaint&, const SimpleFontData*, const Glyph glyphs[], unsigned numGlyphs,
         const SkPoint pos[], const FloatRect& textRect, float deviceScaleFactor) const;
     void paintGlyphsHorizontal(SkCanvas*, const SkPaint&, const SimpleFontData*, const Glyph glyphs[], unsigned numGlyphs,
         const SkScalar xpos[], SkScalar constY, const FloatRect& textRect, float deviceScaleFactor) const;
     void drawGlyphs(SkCanvas*, const SkPaint&, const SimpleFontData*, const GlyphBuffer&, unsigned from, unsigned numGlyphs,
         const FloatPoint&, const FloatRect& textRect, float deviceScaleFactor) const;
     void drawTextBlob(SkCanvas*, const SkPaint&, const SkTextBlob*, const SkPoint& origin) const;
     void drawGlyphBuffer(SkCanvas*, const SkPaint&, const TextRunPaintInfo&, const GlyphBuffer&, const FloatPoint&, float deviceScaleFactor) const;
-    float floatWidthForSimpleText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, IntRectOutsets* glyphBounds = 0) const;
+    float floatWidthForSimpleText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, FloatRectOutsets* glyphBounds = 0) const;
     int offsetForPositionForSimpleText(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForSimpleText(const TextRun&, const FloatPoint&, int h, int from, int to, bool accountForGlyphBounds) const;
 
     bool getEmphasisMarkGlyphData(const AtomicString&, GlyphData&) const;
 
-    float floatWidthForComplexText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts, IntRectOutsets* glyphBounds) const;
+    float floatWidthForComplexText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts, FloatRectOutsets* glyphBounds) const;
     int offsetForPositionForComplexText(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForComplexText(const TextRun&, const FloatPoint&, int h, int from, int to) const;
 
     friend struct SimpleShaper;
 
 public:
     FontSelector* fontSelector() const;
 
     void willUseFontData(UChar32) const;
 
@@ skipping 42 matching lines @@
     // to the next tab stop is less than that, advance an additional tab stop.
     if (distanceToTabStop < fontDescription().letterSpacing())
         distanceToTabStop += baseTabWidth;
 
     return distanceToTabStop;
 }
 
 } // namespace blink
 
 #endif