This test ensures that the descendants of children of non-stacking context overflow-scroll divs do not get promoted needlessly. Only the immediate child of an overflow-scroll div, or an unclipped descendant, need to be promoted.

(GraphicsLayer
  (bounds 1832.00 1682.00)
  (children 1
    (GraphicsLayer
      (bounds 1832.00 1682.00)
      (contentsOpaque 1)
      (drawsContent 1)
      (children 4
        (GraphicsLayer
          (position 28.00 320.00)
          (bounds 402.00 402.00)
          (drawsContent 1)
          (children 4
            (GraphicsLayer
              (position 1.00 1.00)
              (bounds 385.00 385.00)
              (children 1
                (GraphicsLayer
                  (bounds 385.00 950.00)
                  (shouldFlattenTransform 0)
                )
              )
            )
            (GraphicsLayer
              (position 1.00 386.00)
              (bounds 385.00 15.00)
              (drawsContent 1)
            )
            (GraphicsLayer
              (position 386.00 1.00)
              (bounds 15.00 385.00)
              (drawsContent 1)
            )
            (GraphicsLayer
              (position 386.00 386.00)
              (bounds 15.00 15.00)
              (drawsContent 1)
            )
          )
        )
        (GraphicsLayer
          (position 39.00 331.00)
          (bounds 180.00 300.00)
          (contentsOpaque 1)
          (drawsContent 1)
          (backgroundColor #808080)
        )
        (GraphicsLayer
          (position 39.00 961.00)
          (bounds 180.00 300.00)
          (contentsOpaque 1)
          (drawsContent 1)
          (backgroundColor #0000FF)
        )
        (GraphicsLayer
          (position 39.00 641.00)
          (bounds 180.00 300.00)
          (contentsOpaque 1)
          (drawsContent 1)
          (backgroundColor #808080)
          (children 1
            (GraphicsLayer
              (position 0.00 -200.00)
              (bounds 100.00 100.00)
              (contentsOpaque 1)
            )
          )
        )
      )
    )
  )
)