Underline Thickness is not uniform

Source/core/rendering/InlineTextBox.h

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 101 matching lines @@
 public:
     TextRun constructTextRunForInspector(RenderStyle*, const Font&) const;
     virtual FloatRect calculateBoundaries() const OVERRIDE { return FloatRect(x(), y(), width(), height()); }
 
     virtual LayoutRect localSelectionRect(int startPos, int endPos);
     bool isSelected(int startPos, int endPos) const;
     void selectionStartEnd(int& sPos, int& ePos);
 
 protected:
     virtual void paint(PaintInfo&, const LayoutPoint&, LayoutUnit lineTop, LayoutUnit lineBottom) OVERRIDE;
+    virtual void paintDecorationStyle(PaintInfo&, const LayoutPoint&, LayoutUnit lineTop, LayoutUnit lineBottom, float decorationThickness) OVERRIDE;
+    virtual void getPaintDecorationSyle(PaintInfo&, const LayoutPoint&, float *) OVERRIDE;
     virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, LayoutUnit lineTop, LayoutUnit lineBottom) OVERRIDE;
 
 public:
     RenderText& textRenderer() const;
 
 private:
     virtual void deleteLine() OVERRIDE FINAL;
     virtual void extractLine() OVERRIDE FINAL;
     virtual void attachLine() OVERRIDE FINAL;
 
@@ skipping 36 matching lines @@
 private:
     InlineTextBox* m_prevTextBox; // The previous box that also uses our RenderObject
     InlineTextBox* m_nextTextBox; // The next box that also uses our RenderObject
 
     int m_start;
     unsigned short m_len;
 
     unsigned short m_truncation; // Where to truncate when text overflow is applied.  We use special constants to
                       // denote no truncation (the whole run paints) and full truncation (nothing paints at all).
 
+    float m_textDecorationThickness;
+
 protected:
     void paintCompositionBackground(GraphicsContext*, const FloatPoint& boxOrigin, RenderStyle*, const Font&, int startPos, int endPos);
     void paintDocumentMarkers(GraphicsContext*, const FloatPoint& boxOrigin, RenderStyle*, const Font&, bool background);
     void paintCompositionUnderline(GraphicsContext*, const FloatPoint& boxOrigin, const CompositionUnderline&);
 
     // These functions both paint markers and update the DocumentMarker's renderedRect.
     virtual void paintDocumentMarker(GraphicsContext*, const FloatPoint& boxOrigin, DocumentMarker*, RenderStyle*, const Font&, bool grammar);
     virtual void paintTextMatchMarker(GraphicsContext*, const FloatPoint& boxOrigin, DocumentMarker*, RenderStyle*, const Font&);
 
 private:
-    void paintDecoration(GraphicsContext*, const FloatPoint& boxOrigin, TextDecoration, const ShadowList*);
+    void paintDecoration(GraphicsContext*, const FloatPoint& boxOrigin, TextDecoration, const ShadowList*,  float decorationThickness = 0);
     void paintSelection(GraphicsContext*, const FloatPoint& boxOrigin, RenderStyle*, const Font&, Color textColor);
 
     TextRun::ExpansionBehavior expansionBehavior() const
     {
         return (canHaveLeadingExpansion() ? TextRun::AllowLeadingExpansion : TextRun::ForbidLeadingExpansion)
             | (expansion() && nextLeafChild() ? TextRun::AllowTrailingExpansion : TextRun::ForbidTrailingExpansion);
     }
+
+    float getDecorationThickness() { return m_textDecorationThickness; }
+    void setDecorationThickness(float textDecorationThickness) { m_textDecorationThickness = textDecorationThickness; }
 };
 
 DEFINE_INLINE_BOX_TYPE_CASTS(InlineTextBox);
 
 inline RenderText& InlineTextBox::textRenderer() const
 {
     return toRenderText(renderer());
 }
 
 void alignSelectionRectToDevicePixels(FloatRect&);
 
 inline AffineTransform InlineTextBox::rotation(const FloatRect& boxRect, RotationDirection rotationDirection)
 {
     return rotationDirection == Clockwise ? AffineTransform(0, 1, -1, 0, boxRect.x() + boxRect.maxY(), boxRect.maxY() - boxRect.x())
         : AffineTransform(0, -1, 1, 0, boxRect.x() - boxRect.maxY(), boxRect.x() + boxRect.maxY());
 }
 
 } // namespace WebCore
 
 #endif // InlineTextBox_h