Partial revert of r178392

LayoutTests/compositing/layer-creation/spanOverlapsCanvas-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "children": [
         {
           "children": [
             {
               "position": [8, 8],
-              "bounds": [100, 50],
-              "drawsContent": true
+              "bounds": [100, 50]
             },
             {
               "position": [8, 8],
               "bounds": [100, 50],
               "drawsContent": true
             }
           ]
         }
       ]
     }
   ]
 }