This will avoid unnecessary static ranking if smart ranking is used.
Since loader does not need to provided sorted collection of results,
the loading data type has changed from List<> to Set<>. This will also
faster lookup in the Adapter.
Fixes: 38447799
Test: make RunSettingsRoboTests
Change-Id: I448b29bd4e8700c8ec4b5766cbeab4b3087ae39a