Need to repaint its ::first-line background when a block moves.

third_party/WebKit/LayoutTests/platform/linux/fast/repaint/list-marker-2-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "repaintRects": [
         [48, 100, 100, 100],
         [48, 100, 100, 50],
         [30, 185, 7, 19],
         [30, 155, 762, 50],
         [30, 135, 7, 19],
         [30, 100, 762, 104]
       ],
       "paintInvalidationClients": [
         "InlineBox",
         "InlineBox",
         "RootInlineBox",
         "LayoutListItem LI",
         "LayoutListItem LI",
+        "RootInlineBox",
         "LayoutListMarker (anonymous)",
         "LayoutImage IMG id='target'"
       ]
     }
   ]
 }