Merge pull request 'Incremental WebComponents merge' (#2139) from FranklinDM/UXP-contrib:work_wc-incremental-1 into master

Reviewed-on: https://repo.palemoon.org/MoonchildProductions/UXP/pulls/2139

2 files changed, 4 insertions, 6 deletions

diff --git a/devtools/client/inspector/markup/test/doc_markup_anonymous.html b/devtools/client/inspector/markup/test/doc_markup_anonymous.html
index 0ede3ca5ff..bb5389cbe6 100644
--- a/devtools/client/inspector/markup/test/doc_markup_anonymous.html
+++ b/devtools/client/inspector/markup/test/doc_markup_anonymous.html
@@ -25,10 +25,8 @@
   <script>
   "use strict";
   var host = document.querySelector("#shadow");
-  if (host.createShadowRoot) {
-    var root = host.createShadowRoot();
-    root.innerHTML = "<h3>Shadow DOM</h3><select multiple></select>";
-  }
+  var root = host.attachShadow({ mode: "open" });
+  root.innerHTML = "<h3>Shadow DOM</h3><select multiple></select>";
   </script>
 </body>
 </html>
\ No newline at end of file
diff --git a/devtools/server/tests/mochitest/inspector-traversal-data.html b/devtools/server/tests/mochitest/inspector-traversal-data.html
index 45b8c2eded..ada4814d40 100644
--- a/devtools/server/tests/mochitest/inspector-traversal-data.html
+++ b/devtools/server/tests/mochitest/inspector-traversal-data.html
@@ -21,8 +21,8 @@
 
       // Set up a basic shadow DOM
       var host = document.querySelector('#shadow');
-      if (host.createShadowRoot) {
-        var root = host.createShadowRoot();
+      if (host.attachShadow) {
+        let root = host.attachShadow({ mode: "open" });
         root.innerHTML = '<h3>Shadow <em>DOM</em></h3><select multiple></select>';
       }