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

Source/core/layout/line/BreakingContextInlineHeaders.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated.
  *
  * 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 37 matching lines @@
 const unsigned cMaxLineDepth = 200;
 
 class BreakingContext {
 public:
     BreakingContext(InlineBidiResolver& resolver, LineInfo& inLineInfo, LineWidth& lineWidth, LayoutTextInfo& inLayoutTextInfo, FloatingObject* inLastFloatFromPreviousLine, bool appliedStartWidth, LayoutBlockFlow* block)
         : m_resolver(resolver)
         , m_current(resolver.position())
         , m_lineBreak(resolver.position())
         , m_block(block)
         , m_lastObject(m_current.object())
-        , m_nextObject(0)
-        , m_currentStyle(0)
+        , m_nextObject(nullptr)
+        , m_currentStyle(nullptr)
         , m_blockStyle(block->style())
         , m_lineInfo(inLineInfo)
         , m_layoutTextInfo(inLayoutTextInfo)
         , m_lastFloatFromPreviousLine(inLastFloatFromPreviousLine)
         , m_width(lineWidth)
         , m_currWS(NORMAL)
         , m_lastWS(NORMAL)
         , m_preservesNewline(false)
         , m_atStart(true)
         , m_ignoringSpaces(false)
@@ skipping 432 matching lines @@
     return font.width(constructTextRun(layoutText, font,
         style.hyphenString().string(), style, style.direction()));
 }
 
 ALWAYS_INLINE TextDirection textDirectionFromUnicode(WTF::Unicode::Direction direction)
 {
     return direction == WTF::Unicode::RightToLeft
         || direction == WTF::Unicode::RightToLeftArabic ? RTL : LTR;
 }
 
-ALWAYS_INLINE float textWidth(LayoutText* text, unsigned from, unsigned len, const Font& font, float xPos, bool collapseWhiteSpace, HashSet<const SimpleFontData*>* fallbackFonts = 0)
+ALWAYS_INLINE float textWidth(LayoutText* text, unsigned from, unsigned len, const Font& font, float xPos, bool collapseWhiteSpace, HashSet<const SimpleFontData*>* fallbackFonts = nullptr)
 {
     GlyphOverflow glyphOverflow;
     if ((!from && len == text->textLength()) || text->style()->hasTextCombine())
         return text->width(from, len, font, xPos, text->style()->direction(), fallbackFonts, &glyphOverflow);
 
     TextRun run = constructTextRun(text, font, text, from, len, text->styleRef());
     run.setCodePath(text->canUseSimpleFontCodePath() ? TextRun::ForceSimple : TextRun::ForceComplex);
     run.setTabSize(!collapseWhiteSpace, text->style()->tabSize());
     run.setXPos(xPos);
     return font.width(run, fallbackFonts, &glyphOverflow);
@@ skipping 376 matching lines @@
 
     if (style.textIndentType() == TextIndentHanging)
         shouldIndentText = shouldIndentText == IndentText ? DoNotIndentText : IndentText;
 
     return shouldIndentText;
 }
 
 }
 
 #endif // BreakingContextInlineHeaders_h