[gnome-shell] loginDialog: Ensure old timed login timeout is removed before starting a new one

[Ray Strode <halfline src gnome org>]

commit 522a5fe480c45fb35dbe7fe7e2fc48560ad608b5
Author: verdre <gitlab v0yd nl>
Date:   Tue Apr 17 14:51:20 2018 +0200

    loginDialog: Ensure old timed login timeout is removed before starting a new one
    
    Normally, we give the user a 5 second grace period of inactivity before
    starting a timed login operation. Unfortunately, that grace period
    timeout isn't properly removed if the timed login operation is restarted
    during the grace period. That means the timeout handler can
    inadvertently get called multiple times leading to the grace period
    duration getting subtracted from the total animation time more than
    once.
    
    This commit ensures we only ever have one grace period timeout scheduled
    at a time.

 js/gdm/loginDialog.js | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/js/gdm/loginDialog.js b/js/gdm/loginDialog.js
index dc5eaa235..017947689 100644
--- a/js/gdm/loginDialog.js
+++ b/js/gdm/loginDialog.js
@@ -1010,6 +1010,7 @@ var LoginDialog = new Lang.Class({
         this._timedLoginIdleTimeOutId = GLib.timeout_add_seconds(GLib.PRIORITY_DEFAULT, 
_TIMED_LOGIN_IDLE_THRESHOLD,
             () => {
                 this._timedLoginAnimationTime -= _TIMED_LOGIN_IDLE_THRESHOLD;
+                this._timedLoginIdleTimeOutId = 0;
                 hold.release();
                 return GLib.SOURCE_REMOVE;
             });
@@ -1024,6 +1025,12 @@ var LoginDialog = new Lang.Class({
             this._timedLoginBatch = null;
         }
 
+        // Reset previous idle-timeout
+        if (this._timedLoginIdleTimeOutId) {
+            GLib.source_remove(this._timedLoginIdleTimeOutId);
+            this._timedLoginIdleTimeOutId = 0;
+        }
+
         this._timedLoginItem = null;
         this._timedLoginDelay = delay;
         this._timedLoginAnimationTime = delay;