Factor painting code out of RenderBox into a new class called BoxPainter.

Source/core/rendering/RenderImage.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011-2012. All rights reserved.
  *
@@ skipping 462 matching lines @@
 bool RenderImage::foregroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect, unsigned) const
 {
     if (!m_imageResource->hasImage() || m_imageResource->errorOccurred())
         return false;
     if (m_imageResource->cachedImage() && !m_imageResource->cachedImage()->isLoaded())
         return false;
     if (!contentBoxRect().contains(localRect))
         return false;
     EFillBox backgroundClip = style()->backgroundClip();
     // Background paints under borders.
-    if (backgroundClip == BorderFillBox && style()->hasBorder() && !borderObscuresBackground())
+    if (backgroundClip == BorderFillBox && style()->hasBorder() && !style()->borderObscuresBackground())
         return false;
     // Background shows in padding area.
     if ((backgroundClip == BorderFillBox || backgroundClip == PaddingFillBox) && style()->hasPadding())
         return false;
     // Object-position may leave parts of the content box empty, regardless of the value of object-fit.
     if (style()->objectPosition() != RenderStyle::initialObjectPosition())
         return false;
     // Object-fit may leave parts of the content box empty.
     ObjectFit objectFit = style()->objectFit();
     if (objectFit != ObjectFitFill && objectFit != ObjectFitCover)
@@ skipping 133 matching lines @@
         return 0;
 
     ImageResource* cachedImage = m_imageResource->cachedImage();
     if (cachedImage && cachedImage->image() && cachedImage->image()->isSVGImage())
         return toSVGImage(cachedImage->image())->embeddedContentBox();
 
     return 0;
 }
 
 } // namespace blink