[SVG] SVGLength{,List} migration to new SVG property impl.

Source/core/rendering/svg/SVGTextLayoutEngineSpacing.cpp

 /*
  * 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 64 matching lines @@
     kerning *= m_font.size() / m_font.fontMetrics().unitsPerEm();
     return kerning;
 #else
     return false;
 #endif
 }
 
 float SVGTextLayoutEngineSpacing::calculateCSSKerningAndSpacing(const SVGRenderStyle* style, SVGElement* contextElement, UChar currentCharacter)
 {
     float kerning = 0;
-    SVGLength kerningLength = style->kerning();
-    if (kerningLength.unitType() == LengthTypePercentage)
-        kerning = kerningLength.valueAsPercentage() * m_font.pixelSize();
+    RefPtr<SVGLength> kerningLength = style->kerning();
+    if (kerningLength->unitType() == LengthTypePercentage)
+        kerning = kerningLength->valueAsPercentage() * m_font.pixelSize();
     else {
         SVGLengthContext lengthContext(contextElement);
-        kerning = kerningLength.value(lengthContext);
+        kerning = kerningLength->value(lengthContext);
     }
 
     UChar lastCharacter = m_lastCharacter;
     m_lastCharacter = currentCharacter;
 
     if (!kerning && !m_font.letterSpacing() && !m_font.wordSpacing())
         return 0;
 
     float spacing = m_font.letterSpacing() + kerning;
     if (currentCharacter && lastCharacter && m_font.wordSpacing()) {
         if (Font::treatAsSpace(currentCharacter) && !Font::treatAsSpace(lastCharacter))
             spacing += m_font.wordSpacing();
     }
 
     return spacing;
 }
 
 }