1 files changed, 70 insertions, 0 deletions
diff --git a/testing/talos/talos/tests/twinopen/api.js b/testing/talos/talos/tests/twinopen/api.js
new file mode 100644
index 0000000000..e991a7bdd3
--- /dev/null
+++ b/testing/talos/talos/tests/twinopen/api.js
@@ -0,0 +1,70 @@
+"use strict";
+
+/* globals AppConstants, Services */
+
+ChromeUtils.defineESModuleGetters(this, {
+  TalosParentProfiler: "resource://talos-powers/TalosParentProfiler.sys.mjs",
+});
+
+var OPENER_DELAY = 1000; // ms delay between tests
+
+async function openDelay(win) {
+  return new Promise(resolve => {
+    win.setTimeout(resolve, OPENER_DELAY);
+  });
+}
+
+function waitForBrowserPaint() {
+  return new Promise(resolve => {
+    let observer = {
+      observe(doc) {
+        if (
+          !doc.location ||
+          doc.location.href != AppConstants.BROWSER_CHROME_URL
+        ) {
+          return;
+        }
+        Services.obs.removeObserver(observer, "document-element-inserted");
+        doc.ownerGlobal.addEventListener(
+          "MozAfterPaint",
+          evt => {
+            resolve(
+              doc.ownerGlobal.performance.timing.fetchStart + evt.paintTimeStamp
+            );
+          },
+          { once: true }
+        );
+      },
+    };
+    Services.obs.addObserver(observer, "document-element-inserted");
+  });
+}
+
+async function startTest(context) {
+  await TalosParentProfiler.resume("twinopen", true);
+  Cu.forceGC();
+  Cu.forceCC();
+  Cu.forceShrinkingGC();
+  let win = context.appWindow;
+  await openDelay(win);
+  let mozAfterPaint = waitForBrowserPaint();
+
+  // We have to compare time measurements across two windows so we must use
+  // the absolute time.
+  let start = win.performance.timing.fetchStart + win.performance.now();
+  let newWin = win.OpenBrowserWindow();
+  let end = await mozAfterPaint;
+  newWin.close();
+  return end - start;
+}
+
+/* globals ExtensionAPI */
+this.twinopen = class extends ExtensionAPI {
+  getAPI(context) {
+    return {
+      twinopen: {
+        startTest: () => startTest(context),
+      },
+    };
+  }
+};