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

Source/core/layout/svg/SVGTextMetricsBuilder.cpp

 /*
  * 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 55 matching lines @@
     bool m_isComplexText;
     float m_totalWidth;
     TextDirection m_textDirection;
 
     // Simple text only.
     OwnPtr<SimpleShaper> m_simpleShaper;
 };
 
 SVGTextMetricsCalculator::SVGTextMetricsCalculator(LayoutSVGInlineText* text)
     : m_text(text)
-    , m_bidiRun(0)
+    , m_bidiRun(nullptr)
     , m_run(SVGTextMetrics::constructTextRun(text, 0, text->textLength(), text->styleRef().direction()))
     , m_isComplexText(false)
     , m_totalWidth(0)
 {
     const Font& scaledFont = text->scaledFont();
     CodePath codePath = scaledFont.codePath(TextRunPaintInfo(m_run));
     m_isComplexText = codePath == ComplexPath;
     m_run.setCodePath(m_isComplexText ? TextRun::ForceComplex : TextRun::ForceSimple);
 
     if (!m_isComplexText)
@@ skipping 181 matching lines @@
 }
 
 void SVGTextMetricsBuilder::buildMetricsAndLayoutAttributes(LayoutSVGText* textRoot, LayoutSVGInlineText* stopAtLeaf, SVGCharacterDataMap& allCharactersMap)
 {
     ASSERT(textRoot);
     MeasureTextData data(&allCharactersMap);
     walkTree(textRoot, stopAtLeaf, &data);
 }
 
 }