Update the angularjs externs to match the source code. See for an example where the stopPropagation function would be undefined for an event.
@@ -981,6 +981,7 @@ angular.Scope.Event.prototype.name;
angular.Scope.Event.prototype.preventDefault = function() {};
+/** @type {!Function|undefined} */
angular.Scope.Event.prototype.stopPropagation = function() {};
/** @type {!angular.Scope} */
