t
            model = model.__dataHost.__dataHost;
          } while ((options = model.__templatizeOptions) && !options.parentModel)
          this.__parentModel = model;
        }
        return model;
      }
    }

    const MutableTemplateInstanceBase = Polymer.MutableData(TemplateInstanceBase);

    function findMethodHost(template) {
      // Technically this should be the owner of the outermost template.
      // In shadow dom, this is always getRootNode().host, but we can
      // approximate this v