B767 First Officer reported being notified by the flight attendants of a fire in the aft cabin during short final that was safely resolved by the time the aircraft had landed and exited the runway to taxi to the gate.

Narrative

On short final to [Runway] XXR at ZZZ at approximately 1000 feet AGL we received a call from the flight attendants (FA) indicating there was a fire in the aft cabin. This was a line check flight so the Line Check Airman (LCA) was in the jumpseat and took the call. The LCA informed the Captain as the pilot flying (PF) and myself as the pilot monitoring (PM) to the information the LCA was getting. The LCA stayed on the interphone with the FAs gathering information as the PF and PM continued the landing. As we were touching down it was determined the fire was a passengers Portable Electronic Device (PED)/lithium battery type of device; the fire had been extinguished; the device was in a fire containment bag; and the little bit of smoke that had been generated was dissipating. We decided all immediate threat was over and elected to exit the runway and continue taxi to the gate with no need of outside assistance such as Airport Rescue and Firefighting (ARFF) or no need for evacuation. From the first contact to the pilots until the point we were exiting the runway I would estimate it to be 90 - 120 seconds of time elapsed. As we were pulling into the parking space we were told that the passenger might have received minor burns from the event and we requested medical personnel meet the plane. Our entire FA and flight crew worked extremely well in gathering and dispersing information for us to make decisions in an extremely short amount of time during the most critical phase of flight.If we did not have a third pilot; the LCA; who was an active part of the flight deck crew this would have taken the PM out of the landing process and likely necessitating a major response with ARFF or possibly evacuation on the runway due to the two pilots being unable to gather adequate information in a timely manner and make good decisions. If this had been a case in which there was only a single pilot operation there is no telling how this event would have ended but it is doubtful it would have been a conclusion as satisfactory as this one.