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

Source/core/layout/svg/LayoutSVGBlock.h

Index: Source/core/layout/svg/LayoutSVGBlock.h
diff --git a/Source/core/layout/svg/LayoutSVGBlock.h b/Source/core/layout/svg/LayoutSVGBlock.h
index 4022b2b01d8d2bf03ee4781f35eba7bc9ee2ce56..d386ef9e72cffaae781af83ef6b51e786cc0472c 100644
--- a/Source/core/layout/svg/LayoutSVGBlock.h
+++ b/Source/core/layout/svg/LayoutSVGBlock.h
@@ -30,9 +30,9 @@ class LayoutSVGBlock : public LayoutBlockFlow {
 public:
     explicit LayoutSVGBlock(SVGElement*);
 
-    virtual LayoutRect clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* = 0) const override final;
+    virtual LayoutRect clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* = nullptr) const override final;
 
-    virtual void mapLocalToContainer(const LayoutBoxModelObject* paintInvalidationContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip, bool* wasFixed = 0, const PaintInvalidationState* = 0) const override final;
+    virtual void mapLocalToContainer(const LayoutBoxModelObject* paintInvalidationContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip, bool* wasFixed = nullptr, const PaintInvalidationState* = nullptr) const override final;
     virtual const LayoutObject* pushMappingToContainer(const LayoutBoxModelObject* ancestorToStopAt, LayoutGeometryMap&) const override final;
 
     virtual AffineTransform localTransform() const override final { return m_localTransform; }