Bug 1924095 - Don't regenerate backups when cookies are removed by the site. r=backup-reviewers,sthompson

Differential Revision: https://phabricator.services.mozilla.com/D227865

browser/components/backup/BackupService.sys.mjs

@@ -3326,9 +3326,14 @@ export class BackupService extends EventTarget {
       // Intentional fall-through
       case "session-cookie-changed": {
         let notification = subject.QueryInterface(Ci.nsICookieNotification);
+        // A browsingContextId value of 0 means that this deletion was caused by
+        // chrome UI cookie deletion, which is what we care about. If it's not
+        // 0, then a site deleted its own cookie, which we ignore.
         if (
-          notification.action == Ci.nsICookieNotification.COOKIE_DELETED ||
-          notification.action == Ci.nsICookieNotification.ALL_COOKIES_CLEARED
+          (notification.action == Ci.nsICookieNotification.COOKIE_DELETED ||
+            notification.action ==
+              Ci.nsICookieNotification.ALL_COOKIES_CLEARED) &&
+          !notification.browsingContextId
         ) {
           this.#debounceRegeneration();
         }