efl_input_device: add seat_id property

this is the hardware id of a seat which is required in order to match
against objects from other components

@feature

src/lib/efl/interfaces/efl_common_internal.h

@@ -95,6 +95,7 @@ struct _Efl_Input_Device_Data
    Eina_List        *children; /* ref */
    Eina_Stringshare *name;
    Eina_Stringshare *desc;
+   unsigned int      id;
    Efl_Input_Device_Class klass;
    Efl_Input_Device_Sub_Class subclass;
 };

src/lib/efl/interfaces/efl_input_device.c

@@ -101,6 +101,20 @@ _efl_input_device_description_get(Eo *obj EINA_UNUSED, Efl_Input_Device_Data *pd
    return pd->desc;
 }
 
+EOLIAN static void
+_efl_input_device_seat_id_set(Eo *obj EINA_UNUSED, Efl_Input_Device_Data *pd, unsigned int id)
+{
+   EINA_SAFETY_ON_TRUE_RETURN(pd->klass != EFL_INPUT_DEVICE_CLASS_SEAT);
+   pd->id = id;
+}
+
+EOLIAN static unsigned int
+_efl_input_device_seat_id_get(Eo *obj EINA_UNUSED, Efl_Input_Device_Data *pd)
+{
+   EINA_SAFETY_ON_TRUE_RETURN_VAL(pd->klass != EFL_INPUT_DEVICE_CLASS_SEAT, 0);
+   return pd->id;
+}
+
 EOLIAN static Efl_Input_Device *
 _efl_input_device_seat_get(Eo *obj EINA_UNUSED, Efl_Input_Device_Data *pd)
 {

src/lib/efl/interfaces/efl_input_device.eo

@@ -103,6 +103,16 @@ class Efl.Input.Device (Efl.Object)
             seat: Efl.Input.Device; [[The seat this device belongs to.]]
          }
       }
+      @property seat_id {
+         [[Seat id number
+           @since 1.20
+         ]]
+          set{}
+          get{}
+          values {
+             id: uint; [[The id of the seat]]
+          }
+      }
    }
    implements {
       Efl.Object.constructor;