sync-engine-shared - minor refactor
sync-engine-shared - isn't this returning null on exception?
Revert "sync-engine-shared - isn't this returning null on exception?"

This reverts commit 41199debf2f8c73630e524e29df3b7da1be87183.
sync-engine-shared - list finders should return Collections.emptyList() so callers know they'll always get something