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  LayoutView at (0,0) size 800x600
layer at (0,0) size 800x600
  LayoutBlockFlow {HTML} at (0,0) size 800x600
    LayoutBlockFlow {BODY} at (8,8) size 784x584
      LayoutText {#text} at (0,0) size 0x0
layer at (8,8) size 371x119 transparent
  LayoutInline {SPAN} at (0,0) size 371x119 [bgcolor=#808080]
    LayoutText {#text} at (75,22) size 296x27
      text run at (75,22) width 296: "This content should be masked"
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    LayoutText {#text} at (0,94) size 158x27
      text run at (0,94) width 158: "with a soft glow."