efl.canvas.scene: add 'seat_default' property

there seems to be no other way to directly return the default seat object?

ref T7584

Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Differential Revision: https://phab.enlightenment.org/D7956

src/lib/efl/interfaces/efl_canvas_scene.eo

@@ -191,6 +191,21 @@ interface @beta Efl.Canvas.Scene
             seat: Efl.Input.Device; [[The seat or $null if not found.]]
          }
       }
+      @property seat_default {
+         [[Get the default seat attached to this canvas.
+
+           A canvas may have exactly one default seat.
+
+           See also @.device to find a seat by name.
+           See also @.seat to find a seat by id.
+         ]]
+         get {
+            [[Get the default seat.]]
+         }
+         values {
+            seat: Efl.Input.Device; [[The default seat or $null if one does not exist.]]
+         }
+      }
       @property pointer_position {
          get {
             [[This function returns the current known pointer coordinates

src/lib/elementary/efl_ui_win.c

@@ -2616,6 +2616,12 @@ _efl_ui_win_efl_canvas_scene_device_get(const Eo *obj EINA_UNUSED, Efl_Ui_Win_Da
    return efl_canvas_scene_device_get(sd->evas, name);
 }
 
+EOLIAN static Efl_Input_Device *
+_efl_ui_win_efl_canvas_scene_seat_default_get(const Eo *obj EINA_UNUSED, Efl_Ui_Win_Data *sd)
+{
+   return efl_canvas_scene_seat_default_get(sd->evas);
+}
+
 EOLIAN static Efl_Input_Device *
 _efl_ui_win_efl_canvas_scene_seat_get(const Eo *obj EINA_UNUSED, Efl_Ui_Win_Data *sd, int id)
 {

src/lib/elementary/efl_ui_win.eo

@@ -880,6 +880,7 @@ class @beta Efl.Ui.Win extends Efl.Ui.Widget implements Efl.Canvas.Scene, Efl.Ac
       Efl.Gfx.Hint.hint_weight { set; }
       Efl.Gfx.Hint.hint_size_max { set; }
       Efl.Text.text { get; set; }
+      Efl.Canvas.Scene.seat_default { get; }
       Efl.Canvas.Scene.pointer_position { get; }
       Efl.Canvas.Pointer.pointer_inside { get; }
       Efl.Canvas.Scene.image_max_size { get; }

src/lib/evas/canvas/evas_canvas.eo

@@ -965,6 +965,7 @@ class Evas.Canvas extends Efl.Loop_Consumer implements Efl.Canvas.Scene, Efl.Ani
       Efl.Canvas.Pointer.pointer_inside { get; }
       Efl.Canvas.Scene.device { get; }
       Efl.Canvas.Scene.seat { get; }
+      Efl.Canvas.Scene.seat_default { get; }
       Efl.Canvas.Scene.image_max_size { get; }
       Efl.Canvas.Scene.objects_at_xy_get;
       Efl.Canvas.Scene.object_top_at_xy_get;

src/lib/evas/canvas/evas_device.c

@@ -144,6 +144,12 @@ evas_device_get(Evas *eo_e, const char *name)
    return efl_canvas_scene_device_get(eo_e, name);
 }
 
+EOLIAN Efl_Input_Device *
+_evas_canvas_efl_canvas_scene_seat_default_get(Evas *eo_e EINA_UNUSED, Evas_Public_Data *e)
+{
+   return e->default_seat;
+}
+
 EOLIAN Efl_Input_Device *
 _evas_canvas_efl_canvas_scene_seat_get(Evas *eo_e EINA_UNUSED, Evas_Public_Data *e, unsigned int id)
 {