Officially support the system tray on Windows

ts/types/SystemTraySetting.ts

@@ -0,0 +1,22 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { makeEnumParser } from '../util/enum';
+
+// Be careful when changing these values, as they are persisted.
+export enum SystemTraySetting {
+  DoNotUseSystemTray = 'DoNotUseSystemTray',
+  MinimizeToSystemTray = 'MinimizeToSystemTray',
+  MinimizeToAndStartInSystemTray = 'MinimizeToAndStartInSystemTray',
+}
+
+export const shouldMinimizeToSystemTray = (
+  setting: SystemTraySetting
+): boolean =>
+  setting === SystemTraySetting.MinimizeToSystemTray ||
+  setting === SystemTraySetting.MinimizeToAndStartInSystemTray;
+
+export const parseSystemTraySetting = makeEnumParser(
+  SystemTraySetting,
+  SystemTraySetting.DoNotUseSystemTray
+);