Fix popup damage issues when toplevel and/or popup uses geometry

The wlr_xdg_popup_get_toplevel_coords function has the following quirks:

* It does not do anything with the coordinates of the passed popup.
Instead, we are required to add them ourselves, which we do by passing
them to the function as the surface local values.
* It adds the geometry (shadows etc) of the toplevel itself, so the
coordinates are surface local rather than content local. For this
reason, we have to negate the toplevel's geometry
(child->view->geometry).
* I may be wrong, but the popup positions appear to be stored in surface
local coordinates rather than content local coordinates. The geometry
(shadows etc) of the popup itself must be negated (surface->geometry).

sway/desktop/xdg_shell.c

@@ -25,9 +25,12 @@ static void popup_get_root_coords(struct sway_view_child *child,
 	struct sway_xdg_popup *popup = (struct sway_xdg_popup *)child;
 	struct wlr_xdg_surface *surface = popup->wlr_xdg_surface;
 
+	int x_offset = -child->view->geometry.x - surface->geometry.x;
+	int y_offset = -child->view->geometry.y - surface->geometry.y;
+
 	wlr_xdg_popup_get_toplevel_coords(surface->popup,
-		-surface->geometry.x + surface->popup->geometry.x,
-		-surface->geometry.y + surface->popup->geometry.y,
+		x_offset + surface->popup->geometry.x,
+		y_offset + surface->popup->geometry.y,
 		root_sx, root_sy);
 }
 

sway/desktop/xdg_shell_v6.c

@@ -24,9 +24,12 @@ static void popup_get_root_coords(struct sway_view_child *child,
 	struct sway_xdg_popup_v6 *popup = (struct sway_xdg_popup_v6 *)child;
 	struct wlr_xdg_surface_v6 *surface = popup->wlr_xdg_surface_v6;
 
+	int x_offset = -child->view->geometry.x - surface->geometry.x;
+	int y_offset = -child->view->geometry.y - surface->geometry.y;
+
 	wlr_xdg_popup_v6_get_toplevel_coords(surface->popup,
-		-surface->geometry.x + surface->popup->geometry.x,
-		-surface->geometry.y + surface->popup->geometry.y,
+		x_offset + surface->popup->geometry.x,
+		y_offset + surface->popup->geometry.y,
 		root_sx, root_sy);
 }