Delete PaintInvalidationState. It's unused.

sky/engine/core/rendering/RenderLayer.h

Index: sky/engine/core/rendering/RenderLayer.h
diff --git a/sky/engine/core/rendering/RenderLayer.h b/sky/engine/core/rendering/RenderLayer.h
index 18fd2dee5a68678381705313b81903f9c9d5b31a..59fa0eb5dce98fedcefc58f040a6444128291e9c 100644
--- a/sky/engine/core/rendering/RenderLayer.h
+++ b/sky/engine/core/rendering/RenderLayer.h
@@ -223,11 +223,6 @@ public:
 
     bool needsCompositedScrolling() const { return m_scrollableArea && m_scrollableArea->needsCompositedScrolling(); }
 
-    // Computes the position of the given render object in the space of |paintInvalidationContainer|.
-    // FIXME: invert the logic to have paint invalidation containers take care of painting objects into them, rather than the reverse.
-    // This will allow us to clean up this static method messiness.
-    static LayoutPoint positionFromPaintInvalidationContainer(const RenderObject*, const RenderLayerModelObject* paintInvalidationContainer, const PaintInvalidationState* = 0);
-
     bool paintsWithTransform() const;
 
     // Returns true if background phase is painted opaque in the given rect.