import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

toolkit/components/aboutperformance/tests/browser/browser_compartments_script.js

@@ -0,0 +1,29 @@
+
+var carryOn = true;
+
+window.addEventListener("message", e => {
+  console.log("frame content", "message", e);
+  if ("title" in e.data) {
+    document.title = e.data.title;
+  }
+  if ("stop" in e.data) {
+    carryOn = false;
+  }
+});
+
+// Use some CPU.
+var interval = window.setInterval(() => {
+  if (!carryOn) {
+    window.clearInterval(interval);
+    return;
+  }
+
+  // Compute an arbitrary value, print it out to make sure that the JS
+  // engine doesn't discard all our computation.
+  var date = Date.now();
+  var array = [];
+  var i = 0;
+  while (Date.now() - date <= 100) {
+    array[i%2] = i++;
+  }
+}, 300);