This was introduced by commit 396d31a0a7. I just did some further testing and:
* zh_rCN and zh_rTW are the only zh locales you can pick before Android 7;
* Since Android 7, user can use locale list to specify their fallback preferences and there's no need to enforce it.
Therefore this method isn't really necessary and will be thus removed.
To do direct boot, important files need to be moved to device storage (i.e. not as safe storage). The only thing sensitive is user credentials (server settings in each profile) and the config file passed to libss-*.so. In order to implement direct boot, at least the active profile has to be moved/copied to device storage.
This commit keeps profile information (and temporary data used by ProfileConfigFragment) and Shadowsocks config in credential storage and move everything else to device storage. In order to make direct boot work, active profile is also copied into device storage and Shadowsocks config file is created in device storage during direct boot. Cleanup of those information is also implemented.
Fixes#1457.
NB:
* `android:directBootAware` can't be used on application element. That seems to be used by system apps.
* Works fine with multi-user;
* Old GSM files are not migrated (see App.kt) to device storage.