2 files changed, 51 insertions, 0 deletions
diff --git a/devtools/shared/performance-new/moz.build b/devtools/shared/performance-new/moz.build
new file mode 100644
index 0000000000..1d67ce1cc7
--- /dev/null
+++ b/devtools/shared/performance-new/moz.build
@@ -0,0 +1,12 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+DevToolsModules(
+    "recording-utils.js",
+)
+
+with Files("**"):
+    BUG_COMPONENT = ("DevTools", "Performance Tools (Profiler/Timeline)")
diff --git a/devtools/shared/performance-new/recording-utils.js b/devtools/shared/performance-new/recording-utils.js
new file mode 100644
index 0000000000..c221ab6cd5
--- /dev/null
+++ b/devtools/shared/performance-new/recording-utils.js
@@ -0,0 +1,39 @@
+/* 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/. */
+// @ts-check
+"use strict";
+
+/**
+ * This file is for the new performance panel that targets profiler.firefox.com,
+ * not the default-enabled DevTools performance panel.
+ */
+
+/**
+ * @typedef {import("../../client/performance-new/@types/perf").GetActiveBrowserID} GetActiveBrowserID
+ */
+
+/**
+ * Gets the ID of active tab from the browser.
+ *
+ * @type {GetActiveBrowserID}
+ */
+function getActiveBrowserID() {
+  const win = Services.wm.getMostRecentWindow("navigator:browser");
+
+  const browserId = win?.gBrowser?.selectedBrowser?.browsingContext?.browserId;
+  if (browserId) {
+    return browserId;
+  }
+
+  console.error(
+    "Failed to get the active browserId while starting the profiler."
+  );
+  // `0` mean that we failed to ge the active browserId, and it's
+  // treated as null value in the platform.
+  return 0;
+}
+
+module.exports = {
+  getActiveBrowserID,
+};