Delete a bunch of paint invalidation rect computing code.

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 d95b870db211e5a5d99030d468a425cc7292040e..2f35676a9a729c19f538e0549510ff1154aedfce 100644
--- a/sky/engine/core/rendering/RenderLayer.h
+++ b/sky/engine/core/rendering/RenderLayer.h
@@ -235,9 +235,6 @@ public:
     // Adjusts the given rect (in the coordinate space of the RenderObject) to the coordinate space of |paintInvalidationContainer|'s GraphicsLayer backing.
     static void mapRectToPaintInvalidationBacking(const RenderObject*, const RenderLayerModelObject* paintInvalidationContainer, LayoutRect&, const PaintInvalidationState* = 0);
 
-    // Computes the bounding paint invalidation rect for |renderObject|, in the coordinate space of |paintInvalidationContainer|'s GraphicsLayer backing.
-    static LayoutRect computePaintInvalidationRect(const RenderObject*, const RenderLayer* paintInvalidationContainer, const PaintInvalidationState* = 0);
-
     bool paintsWithTransform() const;
 
     // Returns true if background phase is painted opaque in the given rect.