Callers have to pass a number of arguments to build and configure the
VisibleRefFilter. Instead of forcing callers to pass around many
arguments, use an assisted injection factory to create the instance.
Rely on the context Provider<ReviewDb> and Provider<CurrentUser> to
gain database access and user identity within the filter. Given all
current call sites, these should already be populated.
Change-Id: I8197ee773c94f16472d53162fb70791c45899c1b