AccumulatedVisualContext Tree:
  [1] scroll_frame_id=1 (PaintableWithLines(BlockContainer<PRE>#out))
    [2] clip=[8,8 200x100] (PaintableWithLines(BlockContainer(anonymous)))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x121]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x100]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 200x100]
  CompositorWheelHitTestTarget@2 target_scroll_frame_index=0 rect=[8,8 150x50]
  FillRect@2 rect=[8,8 150x50] color=rgb(0, 128, 0)
  DrawGlyphRun@2 rect=[8,8 56x18] translation=[8,21.796875] color=rgb(0, 0, 0)
  CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[10,10 80x40]
  FillRect@0 rect=[10,10 80x40] color=rgb(255, 0, 0)
  DrawGlyphRun@0 rect=[10,10 44x18] translation=[10,23.796875] color=rgb(0, 0, 0)
Restore@0