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

Source/core/layout/LayoutTableCol.h

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 40 matching lines @@
     unsigned span() const { return m_span; }
 
     bool isTableColumnGroupWithColumnChildren() { return firstChild(); }
     bool isTableColumn() const { return style()->display() == TABLE_COLUMN; }
     bool isTableColumnGroup() const { return style()->display() == TABLE_COLUMN_GROUP; }
 
     LayoutTableCol* enclosingColumnGroup() const;
     LayoutTableCol* enclosingColumnGroupIfAdjacentBefore() const
     {
         if (previousSibling())
-            return 0;
+            return nullptr;
         return enclosingColumnGroup();
     }
 
     LayoutTableCol* enclosingColumnGroupIfAdjacentAfter() const
     {
         if (nextSibling())
-            return 0;
+            return nullptr;
         return enclosingColumnGroup();
     }
 
 
     // Returns the next column or column-group.
     LayoutTableCol* nextColumn() const;
 
     const BorderValue& borderAdjoiningCellStartBorder(const LayoutTableCell*) const;
     const BorderValue& borderAdjoiningCellEndBorder(const LayoutTableCell*) const;
     const BorderValue& borderAdjoiningCellBefore(const LayoutTableCell*) const;
     const BorderValue& borderAdjoiningCellAfter(const LayoutTableCell*) const;
 
     virtual const char* name() const override { return "LayoutTableCol"; }
 
 private:
     virtual LayoutObjectChildList* virtualChildren() override { return children(); }
     virtual const LayoutObjectChildList* virtualChildren() const override { return children(); }
 
     virtual bool isOfType(LayoutObjectType type) const override { return type == LayoutObjectLayoutTableCol || LayoutBox::isOfType(type); }
     virtual void updateFromElement() override;
     virtual void computePreferredLogicalWidths() override { ASSERT_NOT_REACHED(); }
 
     virtual void insertedIntoTree() override;
     virtual void willBeRemovedFromTree() override;
 
     virtual bool isChildAllowed(LayoutObject*, const ComputedStyle&) const override;
     virtual bool canHaveChildren() const override;
     virtual DeprecatedPaintLayerType layerTypeRequired() const override { return NoDeprecatedPaintLayer; }
 
-    virtual LayoutRect clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* = 0) const override;
-    virtual void imageChanged(WrappedImagePtr, const IntRect* = 0) override;
+    virtual LayoutRect clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* = nullptr) const override;
+    virtual void imageChanged(WrappedImagePtr, const IntRect* = nullptr) override;
 
     virtual void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
 
     LayoutTable* table() const;
 
     LayoutObjectChildList m_children;
     unsigned m_span;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTableCol, isLayoutTableCol());
 
 }
 
 #endif