As the comments of the whole class says, primary ID is the field used
for checking for equality of the selectors. Current implementation also
checks program type, which is a deprecated field that can be inferred
from primary ID.
Test: open car.Media, add AM station to favorites
Bug: 78296701
Change-Id: I0423f831c2fdca2d1d126ed8a3b8fe40f28022ac