LayoutTests/compositing/masks/mask-layer-size-expected.txt

(GraphicsLayer
  (anchor 0.00 0.00)
  (bounds 800.00 600.00)
  (children 1
    (GraphicsLayer
      (bounds 800.00 600.00)
      (contentsOpaque 1)
      (children 1
        (GraphicsLayer
          (position 10.00 10.00)
          (bounds 400.00 200.00)
          (contentsOpaque 1)
          (mask layer)
            (GraphicsLayer
              (bounds 400.00 200.00)
              (drawsContent 1)
            )
        )
      )
    )
  )
)