input: Use wl_resource_get accessor functions for resources

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
diff --git a/src/text-backend.c b/src/text-backend.c
index 55d4485..cc7d65d 100644
--- a/src/text-backend.c
+++ b/src/text-backend.c
@@ -170,7 +170,7 @@
 		    struct wl_resource *surface)
 {
 	struct text_input *text_input = wl_resource_get_user_data(resource);
-	struct weston_seat *weston_seat = seat->data;
+	struct weston_seat *weston_seat = wl_resource_get_user_data(seat);
 	struct input_method *input_method = weston_seat->input_method;
 	struct text_input *old = weston_seat->input_method->model;
 	struct weston_compositor *ec = text_input->ec;
@@ -205,7 +205,7 @@
 		      struct wl_resource *seat)
 {
 	struct text_input *text_input = wl_resource_get_user_data(resource);
-	struct weston_seat *weston_seat = seat->data;
+	struct weston_seat *weston_seat = wl_resource_get_user_data(seat);
 
 	deactivate_text_input(text_input,
 			      weston_seat->input_method);