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, 4 insertions, 4 deletions

diff --git a/source/blender/makesrna/intern/rna_sculpt_paint.c b/source/blender/makesrna/intern/rna_sculpt_paint.c
index fab3585797a..2e3f41d656b 100644
--- a/source/blender/makesrna/intern/rna_sculpt_paint.c
+++ b/source/blender/makesrna/intern/rna_sculpt_paint.c
@@ -319,7 +319,7 @@ static char *rna_ParticleEdit_path(PointerRNA *UNUSED(ptr))
 static bool rna_Brush_mode_poll(PointerRNA *ptr, PointerRNA value)
 {
   const Paint *paint = ptr->data;
-  Brush *brush = value.id.data;
+  Brush *brush = (Brush *)value.owner_id;
   const uint tool_offset = paint->runtime.tool_offset;
   const eObjectMode ob_mode = paint->runtime.ob_mode;
   UNUSED_VARS_NDEBUG(tool_offset);
@@ -350,10 +350,10 @@ static bool paint_contains_brush_slot(const Paint *paint, const PaintToolSlot *t
 
 static bool rna_Brush_mode_with_tool_poll(PointerRNA *ptr, PointerRNA value)
 {
-  Scene *scene = (Scene *)ptr->id.data;
+  Scene *scene = (Scene *)ptr->owner_id;
   const PaintToolSlot *tslot = ptr->data;
   ToolSettings *ts = scene->toolsettings;
-  Brush *brush = value.id.data;
+  Brush *brush = (Brush *)value.owner_id;
   int mode = 0;
   int slot_index = 0;
 
@@ -438,7 +438,7 @@ static char *rna_Sculpt_path(PointerRNA *UNUSED(ptr))
 
 static char *rna_VertexPaint_path(PointerRNA *ptr)
 {
-  Scene *scene = (Scene *)ptr->id.data;
+  Scene *scene = (Scene *)ptr->owner_id;
   ToolSettings *ts = scene->toolsettings;
   if (ptr->data == ts->vpaint) {
     return BLI_strdup("tool_settings.vertex_paint");