Verify we get the default scroll-blocks-on mode applied to the viewport, no additional layers created (even with an iframe), and no scroll-blocks-on mode applied to any other layer.

{
  "bounds": [800, 600],
  "children": [
    {
      "bounds": [800, 600],
      "scrollBlocksOn": [
        "StartTouch",
        "WheelEvent"
      ],
      "contentsOpaque": true,
      "drawsContent": true,
      "children": [
        {
          "position": [8, 8],
          "bounds": [20, 20]
        }
      ]
    }
  ]
}