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

3 files changed, 7 insertions, 7 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);
   }
 }
 
diff --git a/source/blender/editors/space_nla/nla_channels.c b/source/blender/editors/space_nla/nla_channels.c
index e5c116e85de..456eb783706 100644
--- a/source/blender/editors/space_nla/nla_channels.c
+++ b/source/blender/editors/space_nla/nla_channels.c
@@ -446,7 +446,7 @@ static int nlachannels_pushdown_exec(bContext *C, wmOperator *op)
 
   /* get anim-channel to use (or more specifically, the animdata block behind it) */
   if (channel_index == -1) {
-    PointerRNA adt_ptr = {{NULL}};
+    PointerRNA adt_ptr = {NULL};
 
     /* active animdata block */
     if (nla_panel_context(C, &adt_ptr, NULL, NULL) == 0 || (adt_ptr.data == NULL)) {
@@ -458,7 +458,7 @@ static int nlachannels_pushdown_exec(bContext *C, wmOperator *op)
       return OPERATOR_CANCELLED;
     }
     else {
-      id = adt_ptr.id.data;
+      id = adt_ptr.owner_id;
       adt = adt_ptr.data;
     }
   }
@@ -581,7 +581,7 @@ static int nla_action_unlink_exec(bContext *C, wmOperator *op)
   /* do unlinking */
   if (adt && adt->action) {
     bool force_delete = RNA_boolean_get(op->ptr, "force_delete");
-    ED_animedit_unlink_action(C, adt_ptr.id.data, adt, adt->action, op->reports, force_delete);
+    ED_animedit_unlink_action(C, adt_ptr.owner_id, adt, adt->action, op->reports, force_delete);
   }
 
   return OPERATOR_FINISHED;
diff --git a/source/blender/editors/space_nla/space_nla.c b/source/blender/editors/space_nla/space_nla.c
index 3bdd2804efc..f274f3c93ec 100644
--- a/source/blender/editors/space_nla/space_nla.c
+++ b/source/blender/editors/space_nla/space_nla.c
@@ -522,7 +522,7 @@ static void nla_channel_region_message_subscribe(const struct bContext *UNUSED(C
    * so just whitelist the entire struct for updates
    */
   {
-    wmMsgParams_RNA msg_key_params = {{{0}}};
+    wmMsgParams_RNA msg_key_params = {{0}};
     StructRNA *type_array[] = {
         &RNA_DopeSheet,
     };