rootston: xdg-shell*: Fix get_size() for newly-mapped views

The user-visible issue is that newly-mapped xdg-shell* windows would
sometimes start with their top-left-corner, rather than their center, in
the center of the screen. This is because get_size() would
conservatively fall back on (width, height) == (0, 0) if both
set_window_geometry() had not been called, and it found
view->wlr_surface to be NULL.

But, view->wlr_surface is only set to non-NULL in view_map(). We call
get_size() before this. Fortunately, the wlr_surface in question is
accessible via view->xdg_shell{,_v6}->surface, so always fall back on
that. We can assert its presence instead of further falling back on
(width, height) == (0, 0).

Signed-off-by: Genki Sky <sky@genki.is>

rootston/xdg_shell.c

@@ -135,11 +135,10 @@ static void get_size(const struct roots_view *view, struct wlr_box *box) {
 	if (surface->geometry.width > 0 && surface->geometry.height > 0) {
 		box->width = surface->geometry.width;
 		box->height = surface->geometry.height;
-	} else if (view->wlr_surface != NULL) {
-		box->width = view->wlr_surface->current->width;
-		box->height = view->wlr_surface->current->height;
 	} else {
-		box->width = box->height = 0;
+		assert(surface->surface);
+		box->width = surface->surface->current->width;
+		box->height = surface->surface->current->height;
 	}
 }
 

rootston/xdg_shell_v6.c

@@ -136,11 +136,10 @@ static void get_size(const struct roots_view *view, struct wlr_box *box) {
 	if (surface->geometry.width > 0 && surface->geometry.height > 0) {
 		box->width = surface->geometry.width;
 		box->height = surface->geometry.height;
-	} else if (view->wlr_surface != NULL) {
-		box->width = view->wlr_surface->current->width;
-		box->height = view->wlr_surface->current->height;
 	} else {
-		box->width = box->height = 0;
+		assert(surface->surface);
+		box->width = surface->surface->current->width;
+		box->height = surface->surface->current->height;
 	}
 }