compositor-wayland: Move vfunc setting from set_size to enable

Reviewed-by: Armin Krezović <krezovic.armin@gmail.com>
diff --git a/libweston/compositor-wayland.c b/libweston/compositor-wayland.c
index c6ac5fe..aa7e426 100644
--- a/libweston/compositor-wayland.c
+++ b/libweston/compositor-wayland.c
@@ -1088,11 +1088,21 @@
 	if (b->use_pixman) {
 		if (wayland_output_init_pixman_renderer(output) < 0)
 			goto err_output;
+
+		output->base.repaint = wayland_output_repaint_pixman;
 	} else {
 		if (wayland_output_init_gl_renderer(output) < 0)
 			goto err_output;
+
+		output->base.repaint = wayland_output_repaint_gl;
 	}
 
+	output->base.start_repaint_loop = wayland_output_start_repaint_loop;
+	output->base.assign_planes = NULL;
+	output->base.set_backlight = NULL;
+	output->base.set_dpms = NULL;
+	output->base.switch_mode = wayland_output_switch_mode;
+
 	if (b->sprawl_across_outputs) {
 		wayland_output_set_fullscreen(output,
 					      WL_SHELL_SURFACE_FULLSCREEN_METHOD_DRIVER,
@@ -1166,7 +1176,6 @@
 wayland_output_set_size(struct weston_output *base, int width, int height)
 {
 	struct wayland_output *output = to_wayland_output(base);
-	struct wayland_backend *b = to_wayland_backend(base->compositor);
 	int output_width, output_height;
 
 	/* We can only be called once. */
@@ -1208,17 +1217,6 @@
 	output->base.mm_width = width;
 	output->base.mm_height = height;
 
-	if (b->use_pixman)
-		output->base.repaint = wayland_output_repaint_pixman;
-	else
-		output->base.repaint = wayland_output_repaint_gl;
-
-	output->base.start_repaint_loop = wayland_output_start_repaint_loop;
-	output->base.assign_planes = NULL;
-	output->base.set_backlight = NULL;
-	output->base.set_dpms = NULL;
-	output->base.switch_mode = wayland_output_switch_mode;
-
 	return 0;
 }