When did "brown" become "chocolate"?

[jimmy d]

"It's time for us to rebuild a New Orleans, the one that should be
a chocolate New Orleans. And I don't care what people are
saying in Uptown or wherever they are. This city will be
chocolate at the end of the day. This city will be a majority
African-American city. It's the way God wants
it to be. You can't have it no other way."

New Orleans Mayor - C. Ray Nagin