cc: Add a flag to layers that returns true if the layer is in RSLL.

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 5fd42a49e94ca673599a1841e116fa45238ce26a..195b85b176789a38637b0f3af4de13b1494aff37 100644
--- a/cc/layers/draw_properties.h
+++ b/cc/layers/draw_properties.h
@@ -34,7 +34,8 @@ struct CC_EXPORT DrawProperties {
         index_of_first_descendants_addition(0),
         num_descendants_added(0),
         index_of_first_render_surface_layer_list_addition(0),
-        num_render_surfaces_added(0) {}
+        num_render_surfaces_added(0),
+        last_render_surface_list_membership_index(0u) {}
 
   // Transforms objects from content space to target surface space, where
   // this layer would be drawn.
@@ -118,6 +119,7 @@ struct CC_EXPORT DrawProperties {
   size_t num_descendants_added;
   size_t index_of_first_render_surface_layer_list_addition;
   size_t num_render_surfaces_added;
+  size_t last_render_surface_list_membership_index;
 };
 
 }  // namespace cc