cc: Remove all traces of SkPicture cloning.

cc/resources/picture_layer_tiling.cc

Index: cc/resources/picture_layer_tiling.cc
diff --git a/cc/resources/picture_layer_tiling.cc b/cc/resources/picture_layer_tiling.cc
index a385fc6a59d68412ee58204f4d0a1a19214894d5..3d132e162c7aca32e1b41ff875808962933fab50 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -666,9 +666,8 @@ void PictureLayerTiling::DidBecomeActive() {
     // Tile holds a ref onto a picture pile. If the tile never gets invalidated
     // and recreated, then that picture pile ref could exist indefinitely.  To
     // prevent this, ask the client to update the pile to its own ref.  This
-    // will cause PicturePileImpls and their clones to get deleted once the
-    // corresponding PictureLayerImpl and any in flight raster jobs go out of
-    // scope.
+    // will cause PicturePileImpls to get deleted once the corresponding
+    // PictureLayerImpl and any in flight raster jobs go out of scope.
     it->second->set_picture_pile(active_pile);
   }
 }