diff -r 000000000000 -r 6474c204b198 dom/browser-element/mochitest/browserElement_NextPaint.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/browser-element/mochitest/browserElement_NextPaint.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+/* Any copyright is dedicated to the public domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Bug 808231 - Add mozbrowsernextpaint event.
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+browserElementTestHelpers.setEnabledPref(true);
+browserElementTestHelpers.addPermission();
+
+function runTest() {
+  var iframe = document.createElement('iframe');
+  SpecialPowers.wrap(iframe).mozbrowser = true;
+  document.body.appendChild(iframe);
+
+  // Add a first listener that we'll remove shortly after.
+  iframe.addNextPaintListener(wrongListener);
+
+  var gotFirstNextPaintEvent = false;
+  iframe.addNextPaintListener(function () {
+    ok(!gotFirstNextPaintEvent, 'got the first nextpaint event');
+
+    // Make sure we're only called once.
+    gotFirstNextPaintEvent = true;
+
+    iframe.addNextPaintListener(function () {
+      info('got the second nextpaint event');
+      SimpleTest.finish();
+    });
+
+    // Force the iframe to repaint.
+    SimpleTest.executeSoon(function () iframe.src += '#next');
+  });
+
+  // Remove the first listener to make sure it's not called.
+  iframe.removeNextPaintListener(wrongListener);
+  iframe.src = 'file_browserElement_NextPaint.html';
+}
+
+function wrongListener() {
+  ok(false, 'first listener should have been removed');
+}
+
+addEventListener('testready', runTest);