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, 1 insertions, 1 deletions

diff --git a/source/blender/editors/space_graph/space_graph.c b/source/blender/editors/space_graph/space_graph.c
index 6c5ebf77bf4..91e5ab61dd9 100644
--- a/source/blender/editors/space_graph/space_graph.c
+++ b/source/blender/editors/space_graph/space_graph.c
@@ -527,7 +527,7 @@ static void graph_region_message_subscribe(const struct bContext *UNUSED(C),
    * so just whitelist the entire structs for updates
    */
   {
-    wmMsgParams_RNA msg_key_params = {{{0}}};
+    wmMsgParams_RNA msg_key_params = {{0}};
     StructRNA *type_array[] = {
         &RNA_DopeSheet, /* dopesheet filters */