clutter: Do not export _clutter_stage_do_pick()

The clutter_stage_get_actor_at_pos() calls it almost 1:1 underneath
and is public API, we can have all callers use this, and stop using
this function outside of clutter-stage.c.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1915>

clutter/clutter/clutter-main.c

@@ -776,7 +776,8 @@ update_device_for_event (ClutterStage *stage,
   time_ms = clutter_event_get_time (event);
 
   new_actor =
-    _clutter_stage_do_pick (stage, point.x, point.y, CLUTTER_PICK_REACTIVE);
+    clutter_stage_get_actor_at_pos (stage, CLUTTER_PICK_REACTIVE,
+                                    point.x, point.y);
 
   /* Picking should never fail, but if it does, we bail out here */
   g_return_val_if_fail (new_actor != NULL, NULL);

clutter/clutter/clutter-stage-private.h

@@ -81,11 +81,6 @@ void     _clutter_stage_process_queued_events             (ClutterStage *stage);
 void     _clutter_stage_update_input_devices              (ClutterStage *stage);
 gboolean _clutter_stage_has_full_redraw_queued            (ClutterStage *stage);
 
-ClutterActor *_clutter_stage_do_pick (ClutterStage    *stage,
-                                      float            x,
-                                      float            y,
-                                      ClutterPickMode  mode);
-
 ClutterPaintVolume *_clutter_stage_paint_volume_stack_allocate (ClutterStage *stage);
 void                _clutter_stage_paint_volume_stack_free_all (ClutterStage *stage);
 

clutter/clutter/clutter-stage.c

@@ -170,6 +170,10 @@ static void clutter_stage_update_view_perspective (ClutterStage *stage);
 static void clutter_stage_set_viewport (ClutterStage *stage,
                                         float         width,
                                         float         height);
+static ClutterActor * _clutter_stage_do_pick (ClutterStage   *stage,
+                                              float           x,
+                                              float           y,
+                                              ClutterPickMode mode);
 
 G_DEFINE_TYPE_WITH_PRIVATE (ClutterStage, clutter_stage, CLUTTER_TYPE_ACTOR)
 
@@ -1052,7 +1056,7 @@ clutter_stage_get_view_at (ClutterStage *stage,
   return NULL;
 }
 
-ClutterActor *
+static ClutterActor *
 _clutter_stage_do_pick (ClutterStage   *stage,
                         float           x,
                         float           y,