Fix painting of fixed background images in composited layers

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 504 matching lines @@
     if (objectFit != ObjectFitFill && objectFit != ObjectFitCover)
         return false;
     // Check for image with alpha.
     return m_imageResource->cachedImage() && m_imageResource->cachedImage()->currentFrameKnownToBeOpaque(this);
 }
 
 bool RenderImage::computeBackgroundIsKnownToBeObscured()
 {
     if (!hasBackground())
         return false;
-    return foregroundIsKnownToBeOpaqueInRect(backgroundPaintedExtent(), 0);
+
+    LayoutRect paintedExtent;
+    if (!getBackgroundPaintedExtent(paintedExtent))
+        return false;
+    return foregroundIsKnownToBeOpaqueInRect(paintedExtent, 0);
 }
 
 LayoutUnit RenderImage::minimumReplacedHeight() const
 {
     return m_imageResource->errorOccurred() ? intrinsicSize().height() : LayoutUnit();
 }
 
 HTMLMapElement* RenderImage::imageMap() const
 {
     HTMLImageElement* i = node() && node()->hasTagName(imgTag) ? toHTMLImageElement(node()) : 0;
@@ skipping 109 matching lines @@
         return 0;
 
     ImageResource* cachedImage = m_imageResource->cachedImage();
     if (cachedImage && cachedImage->image() && cachedImage->image()->isSVGImage())
         return toSVGImage(cachedImage->image())->embeddedContentBox();
 
     return 0;
 }
 
 } // namespace WebCore