Remove NonCompositedContentHost -- Take 2

LayoutTests/platform/chromium-win/compositing/backing/no-backing-for-clip-overlap-expected.txt

 This layer should not have backing store.
 This layer should have backing store.
 (GraphicsLayer
   (bounds 800.00 600.00)
   (children 1
     (GraphicsLayer
       (bounds 800.00 600.00)
       (contentsOpaque 1)
+      (drawsContent 1)
       (children 2
         (GraphicsLayer
           (position 8.00 8.00)
           (bounds 342.00 182.00)
           (children 1
             (GraphicsLayer
               (position 1.00 1.00)
               (bounds 340.00 180.00)
               (children 1
                 (GraphicsLayer
@@ skipping 25 matching lines @@
                 )
               )
             )
           )
         )
       )
     )
   )
 )