I don't remember that and I doubt it. Heller is the first time the SC has directly addressed the 2nd since Miller.
As for "It’s a law the city and its supporters say is necessary and successful."
Successful?
Yeah successful here's the same wiki could you at least put your source when you cut and paste.
"Since 1993, crime rates in Washington dropped consistently for over ten years. Along with this trend, gentrification has occurred in many neighborhoods across the District, including Adams Morgan, Logan Circle, Columbia Heights, and the East End of Downtown (Chinatown) and is trending eastward. In the past ten years, the number of homicides has been halved—from 399 in 1994 to 195 in 2005. It is believed by many that the gentrification of these neighborhoods was spurred in part by the extension of Metrorail's Green Line to the Shaw, U Street, Columbia Heights, and Petworth neighborhoods during the late 1990s. The revitalization efforts began first in the Adams Morgan and Logan Circle areas and more recently in Columbia Heights.
In 2005, gentrification began to reach Shaw, Columbia Heights, Le Droit Park, Petworth, Bloomingdale, Eckington, and Trinidad. The transformation of the East End of Downtown/Chinatown into clean, safe areas was aided by the construction of the MCI Center, now Verizon Center, which opened in 1997, and the new Washington Convention Center that opened in 2004 at Mount Vernon Square. As a result, hundreds of brand-new condominiums and apartments were constructed, and many new upscale restaurants, bars, shops, theaters, museums, galleries, and other attractions opened. Prior to around 2000, this was an area of local small businesses, both upscale (including Woodward and Lothrop) and downscale (like the original Sunny's Surplus). Local business in the neighborhood has been replaced by national chain retailers. As a result of gentrification, as well as broader economic forces, home and condo values in Washington, D.C., have skyrocketed. The same is true in nearby Baltimore."