Adding backgroundColor to WebCompositionUnderline and using it for InlineTextBox drawing.

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 156 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).
+private:
+    unsigned getUnderlinePaintStart(const CompositionUnderline&);
+    unsigned getUnderlinePaintEnd(const CompositionUnderline&);
 
 protected:
-    void paintCompositionBackground(GraphicsContext*, const FloatPoint& boxOrigin, RenderStyle*, const Font&, int startPos, int endPos);
+    void paintCompositionBackground(GraphicsContext*, const FloatPoint& boxOrigin, RenderStyle*, const Font&, Color backgroundColor, 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 paintSelection(GraphicsContext*, const FloatPoint& boxOrigin, RenderStyle*, const Font&, Color textColor);
@@ skipping 16 matching lines @@
 
 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