Move settings backup into separate class again

This reverts commit 871f47c2200b58e06f97c0bc1e5f99f412692857,
fixes the blacklist and enables @Presubmit.  Also removes
unnecessary @TargetApi.

Test: run FrameworksCoreTests
Change-Id: I20176b4585d25a023389b3af6fbff63fca432548
1 file changed