AccumulatedVisualContext Tree:
  [0] transform=[1,0,0,1,0,0] origin=(0,0) (ViewportPaintable(Viewport<#document>))
    [1] scroll (PaintableWithLines(BlockContainer<PRE>#out))
      [2] clip=[8,8 100x100] (SVGForeignObjectPaintable(SVGForeignObjectBox<foreignObject>))
        [3] clip=[8,8 100x100] (PaintableWithLines(BlockContainer(anonymous)))
          [4] clip=[8,8 80x80]
            [5] scroll (PaintableWithLines(BlockContainer(anonymous)))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_node_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[0,0 800x121]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,8 784x100]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,8 784x100]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,8 100x100]
  StrokePath@2 path_bounding_rect=[17,17 82x82] thickness=1 color=rgb(0, 0, 0)
  CompositorWheelHitTestTarget@2 target_scroll_node_index=0 rect=[8,8 100x100]
  CompositorWheelHitTestTarget@3 target_scroll_node_index=5 rect=[8,8 80x80]
  CompositorScrollNode@3 scroll_node_index=5 parent_scroll_node_index=0 scrollport_rect=[8,8 80x80] max_scroll_offset=[0,220] is_viewport=false
  CompositorWheelHitTestTarget@5 target_scroll_node_index=5 rect=[8,8 80x300]
  FillRect@5 rect=[8,8 80x300] color=rgb(0, 0, 0)
  PaintScrollBar@3
Restore@0

