Update src/lit-element.ts
Update src/lit-element.ts

Co-Authored-By: Steve Orvell <d25edc07358bc81e1d11f769deba51c8bda13c25@google.com>
lit/lit-element,Polymer/lit-element,Polymer/lit-element,Polymer/lit-element,lit/lit-element,lit/lit-element