AccumulatedVisualContext Tree:
  [0] transform=[1,0,0,1,0,0] origin=(0,0) (ViewportPaintable(Viewport<#document>))
    [1] scroll (ImagePaintable(ImageBox<IMG>))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_node_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[0,0 800x221]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,13 784x200]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,13 784x200]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,13 300x200]
  PaintNestedDisplayList@1 rect=[8,13 300x200]
    SaveLayer@0
      CompositorWheelHitTestTarget@0 target_scroll_node_index=0 rect=[0,0 300x200]
      CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[0,0 300x200]
      FillPath@1 path_bounding_rect=[5,0 55x56]
      FillPath@1 path_bounding_rect=[1,50 55x55]
      FillPath@2 path_bounding_rect=[5,0 55x56]
      FillPath@2 path_bounding_rect=[1,50 55x55]
    Restore@0
    MaskDisplayList for context 2:
      FillPath@0 path_bounding_rect=[4,10 55x56]
    MaskDisplayList for context 3:
      FillPath@0 path_bounding_rect=[4,10 55x56]
    MaskDisplayList for context 4:
      FillPath@0 path_bounding_rect=[4,10 55x56]
Restore@0

