Make scanning decisions based on latest data.

When deciding to kick off a media scan of a newly-downloaded file,
use the latest values from InfoDelta, instead of stale values from
the last database read, which may lead us to skip the scan.

Bug: 29234780
Change-Id: I7ffbcdd1edb9965999b7f5f100f57a9c2933f3a5
2 files changed