Instead of having UserDataImportWarningDialog set an
`onResultDismiss` callback that examines `mustRestartApp`, and having
UserDataActivity set `mustRestartApp`, just have UserDataActivity set
the callback directly.
This approach is no more data-race-y than the previous approach, and it
simplifies the code. (The behavior of restarting the app when the task
finishes is specific to the user data import flow, and there is no
reason for TaskViewModel to be directly aware of it.)
Also make the `Decrypt` method private.
As far as I can tell, the only motivation for exposing the `SetBytes`
and `Reset` methods is to allow `CBoot::SetupWiiMemory` to use the same
`SettingsHandler` instance to read settings data and then write it back.
It seems cleaner to just use two separate instances, and require a given
`SettingsHandler` instance to be used for either writing data to a
buffer or reading data from a buffer, but not both.
A natural next step is to split the `SettingsHandler` class into two
classes, one for writing data and one for reading data. I've deferred
that change for a future PR.
Niel Lebeck