Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/platform/graphics/filters/FilterEffect.cpp

 /*
  * Copyright (C) 2008 Alex Mathews <possessedpenguinbob@gmail.com>
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2012 University of Szeged
  * Copyright (C) 2013 Google 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
@@ skipping 534 matching lines @@
     if (flags & ClipToFilterRegion) {
         absoluteSubregion.intersect(filter->absoluteFilterRegion());
     }
 
     setMaxEffectRect(absoluteSubregion);
     return subregion;
 }
 
 PassRefPtr<SkImageFilter> FilterEffect::createImageFilter(SkiaImageFilterBuilder* builder)
 {
-    return 0;
+    return nullptr;
 }
 
 SkImageFilter::CropRect FilterEffect::getCropRect(const FloatSize& cropOffset) const
 {
     SkRect rect = filter()->filterRegion();
     uint32_t flags = 0;
     FloatRect boundaries = effectBoundaries();
     boundaries.move(cropOffset);
     if (hasX()) {
         rect.fLeft = boundaries.x();
         flags |= SkImageFilter::CropRect::kHasLeft_CropEdge;
     }
     if (hasY()) {
         rect.fTop = boundaries.y();
         flags |= SkImageFilter::CropRect::kHasTop_CropEdge;
     }
     if (hasWidth()) {
         rect.fRight = rect.fLeft + boundaries.width();
         flags |= SkImageFilter::CropRect::kHasRight_CropEdge;
     }
     if (hasHeight()) {
         rect.fBottom = rect.fTop + boundaries.height();
         flags |= SkImageFilter::CropRect::kHasBottom_CropEdge;
     }
     rect = filter()->mapLocalRectToAbsoluteRect(rect);
     return SkImageFilter::CropRect(rect, flags);
 }
 
 } // namespace WebCore