Revert "Performance: Remap multiple items in UI"

This reverts commit 948211679f2a0681421160be0d3b90f507bc0be7.
This commit introduced some regressions in the test suite.
As this change is a core part of blender Bastien and I decided to revert
it as the solution isn't clear and needs more investigation.

The following tests FAILED:
	 62 - blendfile_liblink (SEGFAULT)
	 63 - blendfile_library_overrides (SEGFAULT)

It fails in (id_us_ensure_real)

1 files changed, 4 insertions, 2 deletions

diff --git a/source/blender/blenkernel/BKE_screen.h b/source/blender/blenkernel/BKE_screen.h
index c85ae04a492..63f6fca2a9d 100644
--- a/source/blender/blenkernel/BKE_screen.h
+++ b/source/blender/blenkernel/BKE_screen.h
@@ -38,7 +38,6 @@ struct BlendLibReader;
 struct BlendWriter;
 struct Header;
 struct ID;
-struct IDRemapper;
 struct LibraryForeachIDData;
 struct ListBase;
 struct Menu;
@@ -118,7 +117,10 @@ typedef struct SpaceType {
   bContextDataCallback context;
 
   /* Used when we want to replace an ID by another (or NULL). */
-  void (*id_remap)(struct ScrArea *area, struct SpaceLink *sl, const struct IDRemapper *mappings);
+  void (*id_remap)(struct ScrArea *area,
+                   struct SpaceLink *sl,
+                   struct ID *old_id,
+                   struct ID *new_id);
 
   int (*space_subtype_get)(struct ScrArea *area);
   void (*space_subtype_set)(struct ScrArea *area, int value);