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 800x70]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,10 800x60]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,10 60x60]
  FillPath@1 path_bounding_rect=[0,10 60x60]
  Save@1
    AddClipRect@1 rect=[5,15 50x50]
    DrawGlyphRun@1 rect=[5,15 50x50] translation=[5,23] color=rgb(0, 0, 0)
    DrawGlyphRun@1 rect=[5,15 50x50] translation=[5,33] color=rgb(0, 0, 0)
    DrawGlyphRun@1 rect=[5,15 50x50] translation=[5,43] color=rgb(0, 0, 0)
  Restore@1
Restore@0