Refactor ResourceLoadPriorityOptimizer to avoid walking render tree

Source/core/rendering/RenderImage.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2006 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple 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 58 matching lines @@
     virtual RenderBox* embeddedContentBox() const OVERRIDE FINAL;
     virtual void computeIntrinsicRatioInformation(FloatSize& intrinsicSize, double& intrinsicRatio, bool& isPercentageIntrinsicSize) const OVERRIDE FINAL;
 
     virtual void styleDidChange(StyleDifference, const RenderStyle*) OVERRIDE FINAL;
 
     virtual void imageChanged(WrappedImagePtr, const IntRect* = 0);
 
     void paintIntoRect(GraphicsContext*, const LayoutRect&);
     virtual void paint(PaintInfo&, const LayoutPoint&) OVERRIDE FINAL;
     virtual void layout() OVERRIDE;
-    virtual void didLayout(ResourceLoadPriorityOptimizer&) OVERRIDE;
-    virtual void didScroll(ResourceLoadPriorityOptimizer&) OVERRIDE;
-    void updateImageLoadingPriority(ResourceLoadPriorityOptimizer&);
+    virtual bool updateImageLoadingPriorities() OVERRIDE FINAL;
 
     virtual void intrinsicSizeChanged() OVERRIDE
     {
         if (m_imageResource)
             imageChanged(m_imageResource->imagePtr());
     }
 
 private:
     virtual const char* renderName() const OVERRIDE { return "RenderImage"; }
 
@@ skipping 29 matching lines @@
     float m_imageDevicePixelRatio;
 
     friend class RenderImageScaleObserver;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderImage, isRenderImage());
 
 } // namespace WebCore
 
 #endif // RenderImage_h