1 files changed, 22 insertions, 0 deletions
diff --git a/testing/web-platform/harness/wptrunner/executors/reftest-wait.js b/testing/web-platform/harness/wptrunner/executors/reftest-wait.js
new file mode 100644
index 000000000..a2bc66565
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/reftest-wait.js
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function test(x) {
+  log("classList: " + root.classList);
+  if (!root.classList.contains("reftest-wait")) {
+    observer.disconnect();
+    marionetteScriptFinished();
+  }
+}
+
+var root = document.documentElement;
+var observer = new MutationObserver(test);
+
+observer.observe(root, {attributes: true});
+
+if (document.readyState != "complete") {
+  onload = test
+} else {
+  test();
+}