NEW YORK — On December 14, the Metropolitan Museum of Art announced a transformative promised gift of 220 works by Philip Guston (1913–1980) from the personal collection of Musa Mayer, the artist’s daughter. Consisting of 96 paintings and 124 drawings — the earliest created in 1930 and the latest made in 1980 — the collection represents the full arc of Guston’s career. Ultimately, the gift will position the Met as the largest repository of works by the iconic American painter.