1 files changed, 29 insertions, 0 deletions
diff --git a/toolkit/components/processsingleton/MainProcessSingleton.sys.mjs b/toolkit/components/processsingleton/MainProcessSingleton.sys.mjs
new file mode 100644
index 0000000000..a10493f79b
--- /dev/null
+++ b/toolkit/components/processsingleton/MainProcessSingleton.sys.mjs
@@ -0,0 +1,29 @@
+/* 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/. */
+
+export function MainProcessSingleton() {}
+MainProcessSingleton.prototype = {
+  classID: Components.ID("{0636a680-45cb-11e4-916c-0800200c9a66}"),
+  QueryInterface: ChromeUtils.generateQI([
+    "nsIObserver",
+    "nsISupportsWeakReference",
+  ]),
+
+  observe(subject, topic, data) {
+    switch (topic) {
+      case "app-startup": {
+        // Imported for side-effects.
+        ChromeUtils.importESModule(
+          "resource://gre/modules/CustomElementsListener.sys.mjs"
+        );
+
+        Services.ppmm.loadProcessScript(
+          "chrome://global/content/process-content.js",
+          true
+        );
+        break;
+      }
+    }
+  },
+};