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/interface/interface_region_tooltip.c b/source/blender/editors/interface/interface_region_tooltip.c
index 6aad9e41e7d..f2ca9cebf7b 100644
--- a/source/blender/editors/interface/interface_region_tooltip.c
+++ b/source/blender/editors/interface/interface_region_tooltip.c
@@ -765,8 +765,8 @@ static uiTooltipData *ui_tooltip_data_from_button(bContext *C, uiBut *but)
       }
     }
 
-    if (but->rnapoin.id.data) {
-      const ID *id = but->rnapoin.id.data;
+    if (but->rnapoin.owner_id) {
+      const ID *id = but->rnapoin.owner_id;
       if (ID_IS_LINKED(id)) {
         uiTooltipField *field = text_field_add(data,
                                                &(uiTooltipFormat){
@@ -847,7 +847,7 @@ static uiTooltipData *ui_tooltip_data_from_button(bContext *C, uiBut *but)
       }
     }
 
-    if (but->rnapoin.id.data) {
+    if (but->rnapoin.owner_id) {
       uiTooltipField *field = text_field_add(data,
                                              &(uiTooltipFormat){
                                                  .style = UI_TIP_STYLE_MONO,