C++11: Replace 0 with nullptr where applicable in layout code.

Source/core/layout/svg/SVGTextLayoutAttributesBuilder.h

 /*
  * Copyright (C) Research In Motion Limited 2010-2012. 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 36 matching lines @@
     void buildLayoutAttributesForText(LayoutSVGInlineText*);
 
     void rebuildMetricsForTextLayoutObject(LayoutSVGInlineText*);
 
     // Invoked whenever the underlying DOM tree changes, so that m_textPositions is rebuild.
     void clearTextPositioningElements() { m_textPositions.clear(); }
     unsigned numberOfTextPositioningElements() const { return m_textPositions.size(); }
 
 private:
     struct TextPosition {
-        TextPosition(SVGTextPositioningElement* newElement = 0, unsigned newStart = 0, unsigned newLength = 0)
+        TextPosition(SVGTextPositioningElement* newElement = nullptr, unsigned newStart = 0, unsigned newLength = 0)
             : element(newElement)
             , start(newStart)
             , length(newLength)
         {
         }
 
         SVGTextPositioningElement* element;
         unsigned start;
         unsigned length;
     };
 
     void buildCharacterDataMap(LayoutSVGText&);
     void collectTextPositioningElements(LayoutBoxModelObject&, UChar& lastCharacter);
     void fillCharacterDataMap(const TextPosition&);
 
 private:
     unsigned m_textLength;
     Vector<TextPosition> m_textPositions;
     SVGCharacterDataMap m_characterDataMap;
 };
 
 } // namespace blink
 
 #endif