[gnome-desktop] idle-monitor: Guard against 0 msecs idle intervals

[Bastien Nocera <hadess src gnome org>]

commit 4d9040b097f544154ebdeeee1a90c374ff6aac41
Author: Bastien Nocera <hadess hadess net>
Date:   Fri Mar 2 18:29:53 2018 +0100

    idle-monitor: Guard against 0 msecs idle intervals
    
    As mutter guards against 0 msec idle watches in
    meta_idle_monitor_add_idle_watch()
    
    https://bugzilla.gnome.org/show_bug.cgi?id=793999

 libgnome-desktop/gnome-idle-monitor.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/libgnome-desktop/gnome-idle-monitor.c b/libgnome-desktop/gnome-idle-monitor.c
index b85c096..9dc9043 100644
--- a/libgnome-desktop/gnome-idle-monitor.c
+++ b/libgnome-desktop/gnome-idle-monitor.c
@@ -534,7 +534,8 @@ add_active_watch (GnomeIdleMonitor      *monitor,
 /**
  * gnome_idle_monitor_add_idle_watch:
  * @monitor: A #GnomeIdleMonitor
- * @interval_msec: The idletime interval, in milliseconds
+ * @interval_msec: The idletime interval, in milliseconds. It must be
+ *     a strictly positive value (> 0).
  * @callback: (allow-none): The callback to call when the user has
  *     accumulated @interval_msec milliseconds of idle time.
  * @user_data: (allow-none): The user data to pass to the callback
@@ -563,6 +564,7 @@ gnome_idle_monitor_add_idle_watch (GnomeIdleMonitor        *monitor,
        GnomeIdleMonitorWatch *watch;
 
        g_return_val_if_fail (GNOME_IS_IDLE_MONITOR (monitor), 0);
+       g_return_val_if_fail (interval_msec > 0, 0);
 
        watch = make_watch (monitor,
                            interval_msec,