LibOverride: Fix several issues with resync code.

This commit essentially touches to post-processing of collections and
objects after resync itself has been done, to ensure their proper
instantiation in the scene:

 - Remove a lot of the process in resync case (resynced data are assumed
   to be already instantiated in the scene, unlike override creation
   case).

 - For auto-resync, only do post-processing once after all overrides
   have been resynced (doing it after each individual resynced was
   causing a lot of instantiation glitches, with a lot of unwanted
   extra objects and collections being added to the master collection).

It also deals in a much more reliable way with detection of objects
missing from the scene, by using the new `BKE_scene_objects_as_gset`
utils.

As a bonus this makes auto-resync process slightly faster (only by a few
percents, but that's always good to get).

1 files changed, 2 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_lib_override.h b/source/blender/blenkernel/BKE_lib_override.h
index 0750a3332a8..b9a478f8227 100644
--- a/source/blender/blenkernel/BKE_lib_override.h
+++ b/source/blender/blenkernel/BKE_lib_override.h
@@ -84,7 +84,8 @@ bool BKE_lib_override_library_resync(struct Main *bmain,
                                      struct ViewLayer *view_layer,
                                      struct ID *id_root,
                                      struct Collection *override_resync_residual_storage,
-                                     const bool do_hierarchy_enforce);
+                                     const bool do_hierarchy_enforce,
+                                     const bool do_post_process);
 void BKE_lib_override_library_main_resync(struct Main *bmain,
                                           struct Scene *scene,
                                           struct ViewLayer *view_layer);