If not these system services will end up with inconsistent settings files
when the device runs out of storage.
Delete mangled settings file in PackageManager if the current write fails
so that we don't end up overwriting the backed up version with the
mangled version
Include null check when retrieving fwd locked resource for an existing package
There are three major classes of changes here:
- Avoid writing lines where their values are often empty, false, or some other typical thing.
- Use partial writes to the PrintWriter to avoid creating temporary strings.
- Use StringBuilder where we need to generate real String objects (and where possible cache the result).
