Refactor ResourceLoadPriorityOptimizer to avoid walking render tree

Source/core/fetch/ResourceLoadPriorityOptimizer.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 18 matching lines @@
  */
 
 #ifndef ResourceLoadPriorityOptimizer_h
 #define ResourceLoadPriorityOptimizer_h
 
 #include "core/fetch/ImageResource.h"
 #include "core/fetch/ResourcePtr.h"
 #include "platform/geometry/LayoutRect.h"
 
 #include "wtf/HashMap.h"
+#include "wtf/HashSet.h"
 #include "wtf/OwnPtr.h"
 
 namespace WebCore {
 
 class ResourceLoadPriorityOptimizer {
 public:
     enum VisibilityStatus {
         NotVisible,
         Visible,
     };
+    void notifyImageResourceVisibility(ImageResource*, VisibilityStatus);
+    void updateAllImageResourcePriorities();
+    void addRenderObject(RenderObject*);
+    void removeRenderObject(RenderObject*);
+
+    static ResourceLoadPriorityOptimizer* resourceLoadPriorityOptimizer();
+
+private:
     ResourceLoadPriorityOptimizer();
     ~ResourceLoadPriorityOptimizer();
-    void notifyImageResourceVisibility(ImageResource*, VisibilityStatus);
 
-private:
     void updateImageResourcesWithLoadPriority();
 
     struct ResourceAndVisibility {
         ResourceAndVisibility(ImageResource*, VisibilityStatus);
         ~ResourceAndVisibility();
         ResourcePtr<ImageResource> imageResource;
         VisibilityStatus status;
     };
 
     typedef HashMap<unsigned long, OwnPtr<ResourceAndVisibility> > ImageResourceMap;
     ImageResourceMap m_imageResources;
+
+    typedef HashSet<RenderObject*> RenderObjectSet;

[ojan, 2014/01/23 06:32:59]

Since we only ever add RenderImages, could we tighten up this type?

+    RenderObjectSet m_objects;
 };
 
 }
 
 #endif