This mimics how full text works by silenty dropping results returned from
search that no longer exist. This could be because the search index is slightly
out of sync with reality, or the search engine could simply be broken.
Only silent from the users perspective. We maintain a count in statsd of
the number of titles dropped. This can be monitored over time to
recognize any increases.
Bug: T115756
Change-Id: I2f29d73e258cd448a14d35a2b4902a4fb6f61c68
Various code using the search engine shouldn't need to implement it's
own methods, such as over-fetching, to determine if there are more
results available. This should be knowledge internal to search that is
exposed by a boolean.
Change-Id: Ica094428700637dfdedb723b03f6aeadfe12b9f4
