Refactor ResourceLoadPriorityOptimizer to avoid walking render tree

Source/core/fetch/ResourceLoadPriorityOptimizer.h

Index: Source/core/fetch/ResourceLoadPriorityOptimizer.h
diff --git a/Source/core/fetch/ResourceLoadPriorityOptimizer.h b/Source/core/fetch/ResourceLoadPriorityOptimizer.h
index cb58320a410b54afd1fba7bbe4957f039092f55c..c682eadda9e5e758250c2ebabaa5fbcdba919035 100644
--- a/Source/core/fetch/ResourceLoadPriorityOptimizer.h
+++ b/Source/core/fetch/ResourceLoadPriorityOptimizer.h
@@ -36,6 +36,7 @@
 #include "platform/geometry/LayoutRect.h"
 
 #include "wtf/HashMap.h"
+#include "wtf/HashSet.h"
 #include "wtf/OwnPtr.h"
 
 namespace WebCore {
@@ -46,11 +47,17 @@ public:
         NotVisible,
         Visible,
     };
-    ResourceLoadPriorityOptimizer();
-    ~ResourceLoadPriorityOptimizer();
     void notifyImageResourceVisibility(ImageResource*, VisibilityStatus);
+    void updateAllImageResourcePriorities();
+    void addRenderObject(RenderObject*);
+    void removeRenderObject(RenderObject*);
+
+    static ResourceLoadPriorityOptimizer* resourceLoadPriorityOptimizer();
 
 private:
+    ResourceLoadPriorityOptimizer();
+    ~ResourceLoadPriorityOptimizer();
+
     void updateImageResourcesWithLoadPriority();
 
     struct ResourceAndVisibility {
@@ -62,6 +69,9 @@ private:
 
     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;
 };
 
 }