code: function(callback, context) {
        var objects = this.getObjects(),
            i = objects.length;
        while (i--) {
          callback.call(context, objects[i], i, objects);
        }
        return this;
      }
docs: Iterates over all objects, invoking callback for each one of them
  @method forEachObject
  @return {fabric.Canvas} thisArg