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

Source/core/layout/LayoutReplica.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 16 matching lines @@
  */
 
 #include "config.h"
 #include "core/layout/LayoutReplica.h"
 
 #include "core/paint/ReplicaPainter.h"
 
 namespace blink {
 
 LayoutReplica::LayoutReplica()
-    : LayoutBox(0)
+    : LayoutBox(nullptr)
 {
     // This is a hack. Replicas are synthetic, and don't pick up the attributes of the
     // layoutObjects being replicated, so they always report that they are inline, non-replaced.
     // However, we need transforms to be applied to replicas for reflections, so have to pass
     // the if (!isInline() || isReplaced()) check before setHasTransform().
     setReplaced(true);
 }
 
 LayoutReplica* LayoutReplica::createAnonymous(Document* document)
 {
@@ skipping 20 matching lines @@
     m_maxPreferredLogicalWidth = m_minPreferredLogicalWidth;
     clearPreferredLogicalWidthsDirty();
 }
 
 void LayoutReplica::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     ReplicaPainter(*this).paint(paintInfo, paintOffset);
 }
 
 } // namespace blink