K/V backups are normally only attempted when charging and having an (un-metered) internet connection. However, if the system could not do a backup for more than a day, it ignores these requirements and still attempts a backup run. If a backup storage is used that is only accessible on the internet, but there is no internet connection, the backup attempt will fail. Therefore, we check if our storage requires the internet and if so, we treat it similar to a removable storage, by rejecting backup attempts and suppressing error notifications.
It turned out that call log backup is already in AOSP, but it is
disabled by an undocumented flag. This commit sets this flag (for new
and existing installs) to enable call log backup.
