Fix compositor ignoring mask parenting

There are two aspects to the problem:

- Dependency graph update for compositor preview was missing
  updates flush.

  Apparently, update for new frame style of update will take
  care of flushing, but not the update tagged style of update.

  This goes to a legacy dependency graph and is to be changed
  at some point, but not so close to the release.

- Movie clips were missing from the compositor dependency graph.

This fixes part of T66519.

Reviewers: brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D5256

source/blender/depsgraph/intern/builder/deg_builder_nodes.cc

@@ -1528,6 +1528,19 @@ void DepsgraphNodeBuilder::build_mask(Mask *mask)
                      NodeType::PARAMETERS,
                      OperationCode::MASK_EVAL,
                      function_bind(BKE_mask_eval_update, _1, mask_cow));
+  /* Build parents. */
+  LISTBASE_FOREACH (MaskLayer *, mask_layer, &mask->masklayers) {
+    LISTBASE_FOREACH (MaskSpline *, spline, &mask_layer->splines) {
+      for (int i = 0; i < spline->tot_point; i++) {
+        MaskSplinePoint *point = &spline->points[i];
+        MaskParent *parent = &point->parent;
+        if (parent == NULL || parent->id == NULL) {
+          continue;
+        }
+        build_id(parent->id);
+      }
+    }
+  }
 }
 
 void DepsgraphNodeBuilder::build_movieclip(MovieClip *clip)

source/blender/depsgraph/intern/builder/deg_builder_relations.cc

@@ -2329,6 +2329,24 @@ void DepsgraphRelationBuilder::build_mask(Mask *mask)
   /* Final mask evaluation. */
   OperationKey mask_eval_key(mask_id, NodeType::PARAMETERS, OperationCode::MASK_EVAL);
   add_relation(mask_animation_key, mask_eval_key, "Mask Animation -> Mask Eval");
+  /* Build parents. */
+  LISTBASE_FOREACH (MaskLayer *, mask_layer, &mask->masklayers) {
+    LISTBASE_FOREACH (MaskSpline *, spline, &mask_layer->splines) {
+      for (int i = 0; i < spline->tot_point; i++) {
+        MaskSplinePoint *point = &spline->points[i];
+        MaskParent *parent = &point->parent;
+        if (parent == NULL || parent->id == NULL) {
+          continue;
+        }
+        build_id(parent->id);
+        if (parent->id_type == ID_MC) {
+          OperationKey movieclip_eval_key(
+              parent->id, NodeType::PARAMETERS, OperationCode::MOVIECLIP_EVAL);
+          add_relation(movieclip_eval_key, mask_eval_key, "Movie Clip -> Mask Eval");
+        }
+      }
+    }
+  }
 }
 
 void DepsgraphRelationBuilder::build_movieclip(MovieClip *clip)

source/blender/editors/space_node/node_edit.c

@@ -210,6 +210,7 @@ static void compo_initjob(void *cjv)
 
   /* NOTE: Don't update animation to preserve unkeyed changes, this means can not use
    * evaluate_on_framechange. */
+  DEG_graph_flush_update(bmain, cj->compositor_depsgraph);
   DEG_evaluate_on_refresh(cj->compositor_depsgraph);
 
   bNodeTree *ntree_eval = (bNodeTree *)DEG_get_evaluated_id(cj->compositor_depsgraph,