Fix T73972: Collection in outliner grayed out when all collection children are disabled

There is no reason to have the children enable/disable state to
influence the parent collection. Specially considering that the parent
collection itself can have objects that would be visible.

Reviewed by: dfelinto, brecht

Differential Revision: http://developer.blender.org/D7864

Author: Manuel Castilla

source/blender/blenkernel/intern/layer.c

@@ -694,14 +694,14 @@ int BKE_layer_collection_findindex(ViewLayer *view_layer, const LayerCollection
  * in at least one layer collection. That list is also synchronized here, and
  * stores state like selection. */
 
-static short layer_collection_sync(ViewLayer *view_layer,
-                                   const ListBase *lb_scene,
-                                   ListBase *lb_layer,
-                                   ListBase *new_object_bases,
-                                   short parent_exclude,
-                                   short parent_restrict,
-                                   short parent_layer_restrict,
-                                   unsigned short parent_local_collections_bits)
+static void layer_collection_sync(ViewLayer *view_layer,
+                                  const ListBase *lb_scene,
+                                  ListBase *lb_layer,
+                                  ListBase *new_object_bases,
+                                  short parent_exclude,
+                                  short parent_restrict,
+                                  short parent_layer_restrict,
+                                  unsigned short parent_local_collections_bits)
 {
   /* TODO: support recovery after removal of intermediate collections, reordering, ..
    * For local edits we can make editing operating do the appropriate thing, but for
@@ -732,7 +732,6 @@ static short layer_collection_sync(ViewLayer *view_layer,
 
   /* Add layer collections for any new scene collections, and ensure order is the same. */
   ListBase new_lb_layer = {NULL, NULL};
-  short runtime_flag = 0;
 
   LISTBASE_FOREACH (const CollectionChild *, child, lb_scene) {
     Collection *collection = child->collection;
@@ -763,23 +762,20 @@ static short layer_collection_sync(ViewLayer *view_layer,
     }
 
     /* Sync child collections. */
-    short child_runtime_flag = layer_collection_sync(view_layer,
-                                                     &collection->children,
-                                                     &lc->layer_collections,
-                                                     new_object_bases,
-                                                     lc->flag,
-                                                     child_restrict,
-                                                     child_layer_restrict,
-                                                     local_collections_bits);
+    layer_collection_sync(view_layer,
+                          &collection->children,
+                          &lc->layer_collections,
+                          new_object_bases,
+                          lc->flag,
+                          child_restrict,
+                          child_layer_restrict,
+                          local_collections_bits);
 
     /* Layer collection exclude is not inherited. */
+    lc->runtime_flag = 0;
     if (lc->flag & LAYER_COLLECTION_EXCLUDE) {
-      lc->runtime_flag = 0;
       continue;
     }
-    else {
-      lc->runtime_flag = child_runtime_flag;
-    }
 
     /* We separate restrict viewport and visible view layer because a layer collection can be
      * hidden in the view layer yet (locally) visible in a viewport (if it is not restricted).*/
@@ -846,15 +842,11 @@ static short layer_collection_sync(ViewLayer *view_layer,
 
       lc->runtime_flag |= LAYER_COLLECTION_HAS_OBJECTS;
     }
-
-    runtime_flag |= lc->runtime_flag;
   }
 
   /* Replace layer collection list with new one. */
   *lb_layer = new_lb_layer;
   BLI_assert(BLI_listbase_count(lb_scene) == BLI_listbase_count(lb_layer));
-
-  return runtime_flag;
 }
 
 /**