RNA: Cleanup PointerRNA struct

The old layout of `PointerRNA` was confusing for historic reasons:
```
typedef struct PointerRNA {
  struct {
    void *data;
  } id;

  struct StructRNA *type;
  void *data;
} PointerRNA;
```

This patch updates it to:
```
typedef struct PointerRNA {
  struct ID *owner_id;
  struct StructRNA *type;
  void *data;
} PointerRNA;
```

Throughout the code base `id.data` was replaced with `owner_id`.
Furthermore, many explicit pointer type casts were added which
were implicit before. Some type casts to `ID *` were removed.

Reviewers: brecht, campbellbarton

Differential Revision: https://developer.blender.org/D5558

1 files changed, 3 insertions, 3 deletions

diff --git a/source/blender/makesrna/intern/rna_layer.c b/source/blender/makesrna/intern/rna_layer.c
index c9b51707759..1ad006cbc37 100644
--- a/source/blender/makesrna/intern/rna_layer.c
+++ b/source/blender/makesrna/intern/rna_layer.c
@@ -152,7 +152,7 @@ static int rna_ViewLayer_objects_selected_skip(CollectionPropertyIterator *iter,
 
 static PointerRNA rna_ViewLayer_depsgraph_get(PointerRNA *ptr)
 {
-  ID *id = ptr->id.data;
+  ID *id = ptr->owner_id;
   if (GS(id->name) == ID_SCE) {
     Scene *scene = (Scene *)id;
     ViewLayer *view_layer = (ViewLayer *)ptr->data;
@@ -274,7 +274,7 @@ static void rna_LayerCollection_exclude_update_recursive(ListBase *lb, const boo
 
 static void rna_LayerCollection_exclude_update(Main *bmain, Scene *UNUSED(scene), PointerRNA *ptr)
 {
-  Scene *scene = (Scene *)ptr->id.data;
+  Scene *scene = (Scene *)ptr->owner_id;
   LayerCollection *lc = (LayerCollection *)ptr->data;
   ViewLayer *view_layer = BKE_view_layer_find_from_collection(scene, lc);
 
@@ -294,7 +294,7 @@ static void rna_LayerCollection_exclude_update(Main *bmain, Scene *UNUSED(scene)
 
 static void rna_LayerCollection_update(Main *UNUSED(bmain), Scene *UNUSED(scene), PointerRNA *ptr)
 {
-  Scene *scene = (Scene *)ptr->id.data;
+  Scene *scene = (Scene *)ptr->owner_id;
   LayerCollection *lc = (LayerCollection *)ptr->data;
   ViewLayer *view_layer = BKE_view_layer_find_from_collection(scene, lc);