[gnome-shell/wip/rstrode/rhel-7.9: 78/86] userWidget: Disconnect signal connections on destroy

[Ray Strode <halfline src gnome org>]

commit 413966b3d456bba221cefd47f135620662532bde
Author: Ray Strode <rstrode redhat com>
Date:   Mon Sep 28 22:28:08 2020 -0400

    userWidget: Disconnect signal connections on destroy
    
    At the moment an Avatar (and StIcon) are getting leaked
    every time the screen is locked.
    
    This is because the Avatar class sets up a global signal
    connection that prevents the object from getting garbage
    collected when its actor is destroyed.
    
    This commit adds a destroy handler to disconnect the
    signal connection.

 js/ui/userWidget.js | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/userWidget.js b/js/ui/userWidget.js
index 4e1ce25e92..0a80fa6720 100644
--- a/js/ui/userWidget.js
+++ b/js/ui/userWidget.js
@@ -36,9 +36,19 @@ var Avatar = new Lang.Class({
                                   width: this._iconSize * scaleFactor,
                                   height: this._iconSize * scaleFactor });
 
+        this.actor.connect('destroy', this._onDestroy.bind(this));
+
         // Monitor the scaling factor to make sure we recreate the avatar when needed.
         let themeContext = St.ThemeContext.get_for_stage(global.stage);
-        themeContext.connect('notify::scale-factor', this.update.bind(this));
+        this._scaleFactorChangedId = themeContext.connect('notify::scale-factor', this.update.bind(this));
+    },
+
+    _onDestroy() {
+        if (this._scaleFactorChangedId != 0) {
+            let themeContext = St.ThemeContext.get_for_stage(global.stage);
+            themeContext.disconnect(this._scaleFactorChangedId);
+            this._scaleFactorChangedId = 0;
+        }
     },
 
     setSensitive(sensitive) {