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/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index 9c4d628cec5..e112169d4da 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -3802,7 +3802,7 @@ static void widget_swatch(
 
   widgetbase_draw_ex(&wtb, wcol, show_alpha_checkers);
   if (but->a1 == UI_PALETTE_COLOR &&
-      ((Palette *)but->rnapoin.id.data)->active_color == (int)but->a2) {
+      ((Palette *)but->rnapoin.owner_id)->active_color == (int)but->a2) {
     float width = rect->xmax - rect->xmin;
     float height = rect->ymax - rect->ymin;
     /* find color luminance and change it slightly */