[MM-43656] Flush cookies to disk on finishing custom login (#2076)

* [MM-43656] Flush cookies to disk on finishing custom login

* Fixed a test

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

src/main/app/utils.ts

@@ -212,7 +212,7 @@ export function resizeScreen(browserWindow: BrowserWindow) {
     handle();
 }
 
-function flushCookiesStore(session: Session) {
+export function flushCookiesStore(session: Session) {
     log.debug('Utils.flushCookiesStore');
     session.cookies.flushStore().catch((err) => {
         log.error(`There was a problem flushing cookies:\n${err}`);

src/main/views/webContentEvents.test.js

@@ -25,6 +25,7 @@ jest.mock('electron', () => ({
             setWindowOpenHandler: jest.fn(),
         },
     })),
+    session: {},
 }));
 
 jest.mock('../allowProtocolDialog', () => ({}));
@@ -57,6 +58,10 @@ jest.mock('common/utils/url', () => ({
     isChannelExportUrl: jest.fn(),
 }));
 
+jest.mock('main/app/utils', () => ({
+    flushCookiesStore: jest.fn(),
+}));
+
 jest.mock('../../../electron-builder.json', () => ({
     protocols: [
         {

src/main/views/webContentEvents.ts

@@ -1,7 +1,7 @@
 // Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-import {BrowserWindow, shell, WebContents} from 'electron';
+import {BrowserWindow, session, shell, WebContents} from 'electron';
 import log from 'electron-log';
 
 import {TeamWithTabs} from 'types/config';
@@ -9,6 +9,7 @@ import {TeamWithTabs} from 'types/config';
 import Config from 'common/config';
 import urlUtils from 'common/utils/url';
 
+import {flushCookiesStore} from 'main/app/utils';
 import ContextMenu from 'main/contextMenu';
 
 import WindowManager from '../windows/windowManager';
@@ -70,6 +71,7 @@ export class WebContentsEventManager {
                 return;
             }
             if (this.customLogins[contentID]?.inProgress) {
+                flushCookiesStore(session.defaultSession);
                 return;
             }