Function wrapEvent

docs/tests/v2/es6/js/sanddance.js:34838–34846

(listener)

  }(canvas.getContext);

  function wrapEvent(listener) {
    if (typeof(listener) == "function") {
      return listener;
    } else {
      return function(info) {
        listener.handleEvent(info);
      }
    }
  }

  var addOnContextLostListener = function(listener) {
    onLost_.push(wrapEvent(listener));