Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/svg/graphics/SVGImage.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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.
@@ skipping 175 matching lines @@
     FloatSize adjustedSrcSize = scaledSrc.size();
     adjustedSrcSize.scale(roundedContainerSize.width() / containerSize.width(), roundedContainerSize.height() / containerSize.height());
     scaledSrc.setSize(adjustedSrcSize);
 
     draw(context, dstRect, scaledSrc, compositeOp, blendMode);
 }
 
 PassRefPtr<NativeImageSkia> SVGImage::nativeImageForCurrentFrame()
 {
     if (!m_page)
-        return 0;
+        return nullptr;
 
     OwnPtr<ImageBuffer> buffer = ImageBuffer::create(size());
     if (!buffer)
-        return 0;
+        return nullptr;
 
     drawForContainer(buffer->context(), size(), 1, rect(), rect(), CompositeSourceOver, blink::WebBlendModeNormal);
 
     // FIXME: WK(Bug 113657): We should use DontCopyBackingStore here.
     return buffer->copyImage(CopyBackingStore)->nativeImageForCurrentFrame();
 }
 
 void SVGImage::drawPatternForContainer(GraphicsContext* context, const FloatSize containerSize, float zoom, const FloatRect& srcRect,
     const FloatSize& scale, const FloatPoint& phase, CompositeOperator compositeOp, const FloatRect& dstRect, blink::WebBlendMode blendMode, const IntSize& repeatSpacing)
 {
@@ skipping 201 matching lines @@
 
     return m_page;
 }
 
 String SVGImage::filenameExtension() const
 {
     return "svg";
 }
 
 }