[gnome-shell/gnome-3-38] shellDBus: Properly return from D-Bus methods

[Florian Müllner <fmuellner src gnome org>]

commit 4e28d4021f5cbdf455b069bae555e0c2a302ec0f
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Jun 17 15:42:14 2021 +0200

    shellDBus: Properly return from D-Bus methods
    
    When implementing a D-Bus method synchronously, regular JS methods are
    used. That is, whatever the method returns is passed as return value
    to the method invocation.
    
    However for asynchronous implementations, we need to explicitly return
    a value to the invocation, otherwise the caller will wait until it times
    out eventually.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1891>
    (cherry picked from commit 158920924df53198e85d997b33b6e05afb93f2e8)

 js/ui/shellDBus.js | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/js/ui/shellDBus.js b/js/ui/shellDBus.js
index f672ae73cf..16217c89b5 100644
--- a/js/ui/shellDBus.js
+++ b/js/ui/shellDBus.js
@@ -215,11 +215,13 @@ var GnomeShell = class {
         let sender = invocation.get_sender();
         let [dict] = params;
         Main.osdMonitorLabeler.show(sender, dict);
+        invocation.return_value(null);
     }
 
     HideMonitorLabelsAsync(params, invocation) {
         let sender = invocation.get_sender();
         Main.osdMonitorLabeler.hide(sender);
+        invocation.return_value(null);
     }
 
     _checkOverviewVisibleChanged() {