Store glyph bounds in WordMeasurement to avoid slow path width calc

Source/platform/fonts/Font.h

Index: Source/platform/fonts/Font.h
diff --git a/Source/platform/fonts/Font.h b/Source/platform/fonts/Font.h
index 22afbdd82df688d2836cac42b3fa8eab8cf4c430..5460b6a0d2c0370a1f65f2531bc62b47f8c834e5 100644
--- a/Source/platform/fonts/Font.h
+++ b/Source/platform/fonts/Font.h
@@ -61,32 +61,6 @@ struct TextRunPaintInfo;
 
 struct GlyphData;
 
-struct GlyphOverflow {
-    GlyphOverflow()
-        : left(0)
-        , right(0)
-        , top(0)
-        , 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;
-};
-

[Xianzhu, 2015/06/11 18:22:48]

Moved to Source/core/layout/line/GlyphOverflow.h because it's now used by line
layout only.

 class PLATFORM_EXPORT Font {
 public:
     Font();
@@ -108,7 +82,9 @@ public:
     void drawBidiText(SkCanvas*, const TextRunPaintInfo&, const FloatPoint&, CustomFontNotReadyAction, float deviceScaleFactor, const SkPaint&) const;
     void drawEmphasisMarks(SkCanvas*, const TextRunPaintInfo&, const AtomicString& mark, const FloatPoint&, float deviceScaleFactor, const SkPaint&) const;
 
-    float width(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) 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;
     FloatRect selectionRectForText(const TextRun&, const FloatPoint&, int h, int from = 0, int to = -1, bool accountForGlyphBounds = false) const;
@@ -143,13 +119,13 @@ private:
         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, FloatRectOutsets* glyphBounds = 0) const;
+    float floatWidthForSimpleText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, FloatRect* 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, FloatRectOutsets* glyphBounds) const;
+    float floatWidthForComplexText(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts, FloatRect* glyphBounds) const;
     int offsetForPositionForComplexText(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForComplexText(const TextRun&, const FloatPoint&, int h, int from, int to) const;