When the SFMOMA Artists Gallery got its start 30 years ago, ABBA’s “Take a Chance on Me” dominated the airwaves and David Bowie’s “Heroes” could be had on vinyl. Fast forward to 2008: popular songs like M.I.A.’s “Paper Planes” and Coldplay’s “Viva la Vida” can be downloaded from the internet, and the gallery has become an important exhibition venue and resource for the local art community. This show charts the past three decades through works by 80 of the gallery’s artists.