[SVG] Make metrics passed to calculateGlyphAdvanceAndOrientation const

Source/core/rendering/svg/SVGTextLayoutEngineBaseline.h

 /*
  * Copyright (C) Research In Motion Limited 2010. 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 22 matching lines @@
 
 // Helper class used by SVGTextLayoutEngine to handle 'alignment-baseline' / 'dominant-baseline' and 'baseline-shift'.
 class SVGTextLayoutEngineBaseline {
     WTF_MAKE_NONCOPYABLE(SVGTextLayoutEngineBaseline);
 public:
     SVGTextLayoutEngineBaseline(const Font&);
 
     float calculateBaselineShift(const SVGRenderStyle&, SVGElement* lengthContext) const;
     float calculateAlignmentBaselineShift(bool isVerticalText, const RenderObject* textRenderer) const;
     float calculateGlyphOrientationAngle(bool isVerticalText, const SVGRenderStyle&, const UChar& character) const;
-    float calculateGlyphAdvanceAndOrientation(bool isVerticalText, SVGTextMetrics&, float angle, float& xOrientationShift, float& yOrientationShift) const;
+    float calculateGlyphAdvanceAndOrientation(bool isVerticalText, const SVGTextMetrics&, float angle, float& xOrientationShift, float& yOrientationShift) const;
 
 private:
     EAlignmentBaseline dominantBaselineToAlignmentBaseline(bool isVerticalText, const RenderObject* textRenderer) const;
 
     const Font& m_font;
 };
 
 } // namespace WebCore
 
 #endif