RAL: Eliminate n^2 walk to find repaint containers

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index bbd53eedf4cffd918e1f61829cb4e775fa519cde..936c7039b4ac95534274ac2369101e5249643452 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -814,6 +814,9 @@ public:
     // if painting is root-relative. This is the container that should be passed to the 'forRepaint'
     // methods.
     RenderLayerModelObject* containerForRepaint() const;
+    RenderLayerModelObject* enclosingCompositedContainer() const;
+    RenderLayerModelObject* adjustCompositedContainerForSpecialAncestors(RenderLayerModelObject* repaintContainer) const;
+    bool isRepaintContainer() const;
 
     // Actually do the repaint of rect r for this object which has been computed in the coordinate space
     // of repaintContainer. If repaintContainer is 0, repaint via the view.
@@ -831,7 +834,7 @@ public:
         const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromRepaintContainer, const LayoutRect* newBoundsPtr = 0, const LayoutPoint* newPositionFromRepaintContainer = 0);
 
     // Walk the tree after layout repainting renderers that have changed or moved, updating bounds that have changed, and clearing repaint state.
-    virtual void repaintTreeAfterLayout();
+    virtual void repaintTreeAfterLayout(RenderLayerModelObject& repaintContainer);
 
     virtual void repaintOverflow();
     void repaintOverflowIfNeeded();