Function setupValidity

test/angular/1.6/angular.js:24189–24192

(instance)

// helper methods
function setupValidity(instance) {
  instance.$$classCache = {};
  instance.$$classCache[INVALID_CLASS] = !(instance.$$classCache[VALID_CLASS] = instance.$$element.hasClass(VALID_CLASS));
}
function addSetValidityMethod(context) {
  var clazz = context.clazz,
      set = context.set,