Viewport <#document> at [0,0] [0+0+0 800 0+0+0] [0+0+0 600 0+0+0] [BFC] children: not-inline
  BlockContainer <html> at [0,0] [0+0+0 800 0+0+0] [0+0+0 90 0+0+0] [BFC] children: not-inline
    BlockContainer <body> at [0,0] [0+0+0 800 0+0+0] [0+0+0 90 0+0+0] children: not-inline
      BlockContainer <div> at [0,0] [0+0+0 800 0+0+0] [0+0+0 90 0+0+0] [BFC] children: inline
        InlineNode <span> at [0,5] [0+0+0 10 0+0+0] [0+0+0 10 0+0+0]
          frag 0 from TextNode start: 0, length: 1, rect: [0,5 10x10] baseline: 8
              "a"
          frag 0 from BlockContainer start: 0, length: 0, rect: [0,20 800x20] baseline: 0
          TextNode <#text> (not painted)
          BlockContainer <div> at [0,20] [0+0+0 800 0+0+0] [0+0+0 20 0+0+50] children: inline
            frag 0 from TextNode start: 0, length: 1, rect: [0,25 10x10] baseline: 8
                "b"
            TextNode <#text> (not painted)
      BlockContainer <(anonymous)> at [0,90] [0+0+0 800 0+0+0] [0+0+0 0 0+0+0] children: inline
        TextNode <#text> (not painted)

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x90]
    PaintableWithLines (BlockContainer<BODY>) [0,0 800x90]
      PaintableWithLines (BlockContainer<DIV>) [0,0 800x90]
        InlinePaintable (InlineNode<SPAN>) [0,5 10x10]
          PaintableWithLines (BlockContainer<DIV>) [0,20 800x20]
      PaintableWithLines (BlockContainer(anonymous)) [0,90 800x0]

SC for Viewport<#document> [0,0 800x600] (z-index: auto)
 SC for BlockContainer<HTML> [0,0 800x90] (z-index: auto)
