angular/angular.js — pull request #3388 by matsko (2013-07-29 20:27:33+00:00)
Title: fix(ngClass): ensure ngClass doesn't fire addClass or removeClass with an empty string

If ngClass fires off an add or removeClass whilst the opposite animation is going on then
the animation will be skipped. The default behavior of ngClass was executing remoteClass
with an empty string while addClass had just fired. This commit fixes that bug.