wl backend: add wlr_input_device_is_wl

backend/wayland/wl_seat.c

@@ -203,6 +203,10 @@ static struct wlr_input_device_impl input_device_impl = {
 	.destroy = input_device_destroy
 };
 
+bool wlr_input_device_is_wl(struct wlr_input_device *dev) {
+	return dev->impl == &input_device_impl;
+}
+
 static struct wlr_input_device *allocate_device(struct wlr_wl_backend *backend,
 		enum wlr_input_device_type type) {
 	struct wlr_wl_input_device *wlr_wl_dev;

include/backend/wayland.h

@@ -8,7 +8,6 @@
 #include <wlr/render/egl.h>
 #include <wlr/backend/wayland.h>
 #include <wlr/types/wlr_box.h>
-#include <wlr/types/wlr_input_device.h>
 #include <wayland-util.h>
 
 struct wlr_wl_backend {

include/wlr/backend/wayland.h

@@ -4,6 +4,7 @@
 #include <wayland-client.h>
 #include <wayland-server.h>
 #include <wlr/backend.h>
+#include <wlr/types/wlr_input_device.h>
 #include <wlr/types/wlr_output.h>
 #include <stdbool.h>
 
@@ -26,6 +27,11 @@ struct wlr_output *wlr_wl_output_create(struct wlr_backend *backend);
  */
 bool wlr_backend_is_wl(struct wlr_backend *backend);
 
+/**
+ * True if the given input device is a wlr_wl_input_device.
+ */
+bool wlr_input_device_is_wl(struct wlr_input_device *device);
+
 /**
  * True if the given output is a wlr_wl_backend_output.
  */