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

Source/core/layout/line/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 22 matching lines @@
 class DocumentMarker;
 class GraphicsContext;
 
 const unsigned short cNoTruncation = USHRT_MAX;
 const unsigned short cFullTruncation = USHRT_MAX - 1;
 
 class InlineTextBox : public InlineBox {
 public:
     InlineTextBox(LayoutObject& obj, int start, unsigned short length)
         : InlineBox(obj)
-        , m_prevTextBox(0)
-        , m_nextTextBox(0)
+        , m_prevTextBox(nullptr)
+        , m_nextTextBox(nullptr)
         , m_start(start)
         , m_len(length)
         , m_truncation(cNoTruncation)
     {
         setIsText(true);
     }
 
     LayoutText& layoutObject() const { return toLayoutText(InlineBox::layoutObject()); }
 
     virtual void destroy() override final;
@@ skipping 25 matching lines @@
     virtual LayoutUnit lineHeight() const override final;
 
     bool getEmphasisMarkPosition(const ComputedStyle&, TextEmphasisPosition&) const;
 
     LayoutRect logicalOverflowRect() const;
     void setLogicalOverflowRect(const LayoutRect&);
     LayoutUnit logicalTopVisualOverflow() const { return logicalOverflowRect().y(); }
     LayoutUnit logicalBottomVisualOverflow() const { return logicalOverflowRect().maxY(); }
 
     // charactersWithHyphen, if provided, must not be destroyed before the TextRun.
-    TextRun constructTextRun(const ComputedStyle&, const Font&, StringBuilder* charactersWithHyphen = 0) const;
-    TextRun constructTextRun(const ComputedStyle&, const Font&, StringView, int maximumLength, StringBuilder* charactersWithHyphen = 0) const;
+    TextRun constructTextRun(const ComputedStyle&, const Font&, StringBuilder* charactersWithHyphen = nullptr) const;
+    TextRun constructTextRun(const ComputedStyle&, const Font&, StringView, int maximumLength, StringBuilder* charactersWithHyphen = nullptr) const;
 
 #ifndef NDEBUG
     virtual void showBox(int = 0) const override;
 #endif
     virtual const char* boxName() const override;
     virtual String debugName() const override;
 
     String text() const;
 
 public:
@@ skipping 71 matching lines @@
     }
 };
 
 DEFINE_INLINE_BOX_TYPE_CASTS(InlineTextBox);
 
 void alignSelectionRectToDevicePixels(LayoutRect&);
 
 } // namespace blink
 
 #endif // InlineTextBox_h