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

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x221]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,13 784x200]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,13 784x200]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,13 300x200]
  PaintNestedDisplayList@1 rect=[8,13 300x200]
    SaveLayer@0
      CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[0,0 300x200]
      CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 300x200]
      FillPath@1 path_bounding_rect=[5,0 55x56]
      FillPath@1 path_bounding_rect=[1,50 55x55]
      Save@1
        AddClipRect@1 rect=[4,10 55x55]
        SaveLayer@1
          FillPath@1 path_bounding_rect=[5,0 55x56]
          FillPath@1 path_bounding_rect=[1,50 55x55]
          ApplyEffects@1 opacity=1 has_filter=false
            PaintNestedDisplayList@1 rect=[4,10 55x55]
              Translate@0 delta=[-4,-10]
              FillPath@0 path_bounding_rect=[4,10 55x56]
          Restore@1
        Restore@1
      Restore@1
    Restore@0
Restore@0
