From 3af9f3407b492156a78d850cb373219c8b4b03f8 Mon Sep 17 00:00:00 2001
From: Steven Orvell <sorvell@google.com>
Date: Fri, 12 Apr 2019 17:37:22 -0700
Subject: [PATCH] Use `attachShadow({shadyUpgradeFragment})`

---
 lib/mixins/element-mixin.js | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/lib/mixins/element-mixin.js b/lib/mixins/element-mixin.js
index 7690978cea..7c28589f9a 100644
--- a/lib/mixins/element-mixin.js
+++ b/lib/mixins/element-mixin.js
@@ -672,12 +672,8 @@ export const ElementMixin = dedupingMixin(base => {
       if (n.attachShadow) {
         if (dom) {
           if (!n.shadowRoot) {
-            if (window.ShadyDOM && ShadyDOM['attachDom']) {
-              ShadyDOM['attachDom'](dom, this, {mode: 'open'});
-            } else {
-              n.attachShadow({mode: 'open'});
-              n.shadowRoot.appendChild(dom);
-            }
+            n.attachShadow({mode: 'open', shadyUpgradeFragment: dom});
+            n.shadowRoot.appendChild(dom);
           }
           if (syncInitialRender && window.ShadyDOM) {
             ShadyDOM.flushInitial(n.shadowRoot);