AccumulatedVisualContext Tree:
  [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]
  Save@1
    AddClipRect@1 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@1
Restore@0