Remove the HasOwnBackingButPaintsIntoAncestor compositing state.

LayoutTests/platform/linux/compositing/backing/no-backing-for-perspective-expected.txt

 This layer should not have backing store.
 This layer should not have backing store.
 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "children": [
         {
           "position": [8, 8],
           "bounds": [342, 244],
+          "drawsContent": true,
           "children": [
             {
               "bounds": [342, 244],
               "shouldFlattenTransform": false,
               "transform": [
                 [1, 0, 0, 0],
                 [0, 1, 0, 0],
                 [0, 0, 1, -0.002],
                 [0, 0, 0, 1]
               ],
               "children": [
                 {
                   "position": [21, 41],
                   "bounds": [342, 182],
+                  "drawsContent": true,
                   "children": [
                     {
                       "bounds": [342, 182],
                       "shouldFlattenTransform": false,
                       "transform": [
                         [1, 0, 0, 0],
                         [0, 1, 0, 0],
                         [0, 0, 1, -0.002],
                         [0, 0, 0, 1]
                       ],
@@ skipping 17 matching lines @@
                 }
               ]
             }
           ]
         }
       ]
     }
   ]
 }