Delete unused paint invalidation function.

sky/engine/core/rendering/RenderObject.h

Index: sky/engine/core/rendering/RenderObject.h
diff --git a/sky/engine/core/rendering/RenderObject.h b/sky/engine/core/rendering/RenderObject.h
index 7db8dab0eec99e3ea87a4b992991ca009c6f0a6f..fff79736b3b4ee2c97770e9d1e995e6d27195d52 100644
--- a/sky/engine/core/rendering/RenderObject.h
+++ b/sky/engine/core/rendering/RenderObject.h
@@ -311,10 +311,6 @@ public:
             setNeedsLayout();
     }
 
-    // Returns the smallest rectangle enclosing all of the painted content
-    // respecting clipping, masking, filters, opacity, stroke-width and markers
-    virtual FloatRect paintInvalidationRectInLocalCoordinates() const;
-
     // SVG uses FloatPoint precise hit testing, and passes the point in parent
     // coordinates instead of in paint invalidaiton container coordinates. Eventually the
     // rest of the rendering tree will move to a similar model.