In ReplicationCoordinatorImpl::waitUntilOpTimeForRead(), we check if majority read can be satisfied for the following settings.

getSettings().isMajorityReadConcernEnabled()
getReplicationMode()
_externalState->snapshotsEnabled()

We need to either duplicate them or pull them out of waitUntilOpTimeForRead() to read_concern.cpp. We also need to audit the callers of waitUntilOpTimeForRead() if we change it.