The mosque was built after Abu Huraira's (ra) death.
Plus it was reported by others than Abu Huraira (ra).
Sayyidina an-Nawas b. Sam'an (رضي الله عنه) (while relating the story of Dajjal) reports: "Meantime when Dajjal will be engaged in perpetrating such deeds, God shall send Christ, son of Mary. Christ (عليه السلام) will descend near the white tower in the eastern quarter of Damascus, wearing two pieces of yellow garment and resting his hands upon the arms of two angels. When he will bend his head, it would seem that drops of water would fall down from his head and when he will raise his head it would seem as if pearls would be trickling in the form of drops. Any infidel who will be within reach of the air of his breath, and the air of his breath willr each as far as his eye would see - will not escape death. Later the son of Mary will pursue Dajjal and will overtake him at the gate of Lydda [Please note that Lod (modern Lydda) is situated at a distance of few miles from Tel Aviv, the capital of the State of Israel in Palestine. The Jews have built a large air-base at this place.] and put him to death." (Muslim, Dhikr Dajjal; Abu Dawud, Kitab ul-Malahim, Bab: Khuruj; Dajjal; Tirmidhi, Abwab ul-Fitan; Bab: Fi Fitna al-Dajjal; Ibn Majah, Kitab ul-Fitna, Bab: Fitna al-Dajjal) http://www.muftisays.com/blog/Seifeddine-M/1271_28-02-2011/ahadeeth-pertaining-to-the-descent-of-sayyidina-isa-(jesus-.-peace-be-upon-him
Besides, nobody knows if it is the Ummayi Mosque.