Refactor ResourceLoadPriorityOptimizer to avoid walking render tree

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 45 matching lines @@
 using namespace HTMLNames;
 
 RenderImage::RenderImage(Element* element)
     : RenderReplaced(element, IntSize())
     , m_needsToSetSizeForAltText(false)
     , m_didIncrementVisuallyNonEmptyPixelCount(false)
     , m_isGeneratedContent(false)
     , m_imageDevicePixelRatio(1.0f)
 {
     updateAltText();
+    ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->addRenderObject(this);
 }
 
 RenderImage* RenderImage::createAnonymous(Document* document)
 {
     RenderImage* image = new RenderImage(0);
     image->setDocumentForAnonymous(document);
     return image;
 }
 
 RenderImage::~RenderImage()
@@ skipping 495 matching lines @@
         m_altText = toHTMLImageElement(node())->altText();
 }
 
 void RenderImage::layout()
 {
     LayoutRectRecorder recorder(*this);
     RenderReplaced::layout();
     updateInnerContentRect();
 }
 
-void RenderImage::didLayout(ResourceLoadPriorityOptimizer& optimizer)
-{
-    RenderReplaced::didLayout(optimizer);
-    updateImageLoadingPriority(optimizer);
-}
-
-void RenderImage::didScroll(ResourceLoadPriorityOptimizer& optimizer)
-{
-    RenderReplaced::didScroll(optimizer);
-    updateImageLoadingPriority(optimizer);
-}
-
-void RenderImage::updateImageLoadingPriority(ResourceLoadPriorityOptimizer& optimizer)
+bool RenderImage::updateImageLoadingPriorities()
 {
     if (!m_imageResource || !m_imageResource->cachedImage() || m_imageResource->cachedImage()->isLoaded())
-        return;
+        return false;
 
     LayoutRect viewBounds = viewRect();
     LayoutRect objectBounds = absoluteContentBox();
 
     // The object bounds might be empty right now, so intersects will fail since it doesn't deal
     // with empty rects. Use LayoutRect::contains in that case.
     bool isVisible;
     if (!objectBounds.isEmpty())
         isVisible =  viewBounds.intersects(objectBounds);
     else
         isVisible = viewBounds.contains(objectBounds);
 
     ResourceLoadPriorityOptimizer::VisibilityStatus status = isVisible ?
         ResourceLoadPriorityOptimizer::Visible : ResourceLoadPriorityOptimizer::NotVisible;
 
-    optimizer.notifyImageResourceVisibility(m_imageResource->cachedImage(), status);
+    ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->notifyImageResourceVisibility(m_imageResource->cachedImage(), status);
+
+    return true;
 }
 
 void RenderImage::computeIntrinsicRatioInformation(FloatSize& intrinsicSize, double& intrinsicRatio, bool& isPercentageIntrinsicSize) const
 {
     RenderReplaced::computeIntrinsicRatioInformation(intrinsicSize, intrinsicRatio, isPercentageIntrinsicSize);
 
     // Our intrinsicSize is empty if we're rendering generated images with relative width/height. Figure out the right intrinsic size to use.
     if (intrinsicSize.isEmpty() && (m_imageResource->imageHasRelativeWidth() || m_imageResource->imageHasRelativeHeight())) {
         RenderObject* containingBlock = isOutOfFlowPositioned() ? container() : this->containingBlock();
         if (containingBlock->isBox()) {
@@ skipping 23 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