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/editors/space_nla/nla_buttons.c b/source/blender/editors/space_nla/nla_buttons.c
index 719efc7eeac..126b20a028e 100644
--- a/source/blender/editors/space_nla/nla_buttons.c
+++ b/source/blender/editors/space_nla/nla_buttons.c
@@ -268,8 +268,8 @@ static void nla_panel_animdata(const bContext *C, Panel *pa)
   /* icon + id-block name of block where AnimData came from to prevent
    * accidentally changing the properties of the wrong action
    */
-  if (adt_ptr.id.data) {
-    ID *id = adt_ptr.id.data;
+  if (adt_ptr.owner_id) {
+    ID *id = adt_ptr.owner_id;
     PointerRNA id_ptr;
 
     RNA_id_pointer_create(id, &id_ptr);
@@ -513,7 +513,7 @@ static void nla_panel_modifiers(const bContext *C, Panel *pa)
   for (fcm = strip->modifiers.first; fcm; fcm = fcm->next) {
     col = uiLayoutColumn(pa->layout, true);
 
-    ANIM_uiTemplate_fmodifier_draw(col, strip_ptr.id.data, &strip->modifiers, fcm);
+    ANIM_uiTemplate_fmodifier_draw(col, strip_ptr.owner_id, &strip->modifiers, fcm);
   }
 }