Add a sanity check to ensure that CDP doesn't hit a cycle

cc/layers/draw_properties.h

Index: cc/layers/draw_properties.h
diff --git a/cc/layers/draw_properties.h b/cc/layers/draw_properties.h
index 7cf89e756cab62bdaec717c52ecf2fdfd814690a..ff5abd95a5474e76aa0ef2831d3dc86c13bbff48 100644
--- a/cc/layers/draw_properties.h
+++ b/cc/layers/draw_properties.h
@@ -34,6 +34,7 @@ struct CC_EXPORT DrawProperties {
         layer_or_descendant_has_input_handler(false),
         has_child_with_a_scroll_parent(false),
         sorted_for_recursion(false),
+        visited(false),
         index_of_first_descendants_addition(0),
         num_descendants_added(0),
         index_of_first_render_surface_layer_list_addition(0),
@@ -123,6 +124,9 @@ struct CC_EXPORT DrawProperties {
   // layer will be visited while computing draw properties has been determined.
   bool sorted_for_recursion;
 
+  // This is used to sanity-check CDP and ensure that we don't revisit a layer.
+  bool visited;
+
   // If this layer is visited out of order, its contribution to the descendant
   // and render surface layer lists will be put aside in a temporary list.
   // These values will allow for an efficient reordering of these additions.