diff -r 000000000000 -r 6474c204b198 dom/browser-element/mochitest/browserElement_CookiesNotThirdParty.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/browser-element/mochitest/browserElement_CookiesNotThirdParty.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,51 @@
+/* Any copyright is dedicated to the public domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Bug 806127 - Test that cookies set by <iframe mozbrowser> are not considered
+// third-party.
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+browserElementTestHelpers.setEnabledPref(true);
+browserElementTestHelpers.addPermission();
+
+function runTest() {
+  const innerPage = 'http://example.com/tests/dom/browser-element/mochitest/file_browserElement_CookiesNotThirdParty.html';
+
+  var iframe = document.createElement('iframe');
+  SpecialPowers.wrap(iframe).mozbrowser = true;
+
+  iframe.addEventListener('mozbrowsershowmodalprompt', function(e) {
+    if (e.detail.message == 'next') {
+      iframe.src = innerPage + '?step=2';
+      return;
+    }
+
+    if (e.detail.message.startsWith('success:')) {
+      ok(true, e.detail.message);
+      return;
+    }
+
+    if (e.detail.message.startsWith('failure:')) {
+      ok(false, e.detail.message);
+      return;
+    }
+
+    if (e.detail.message == 'finish') {
+      SimpleTest.finish();
+    }
+  });
+
+  // innerPage will set a cookie and then alert('next').  We'll load
+  // innerPage?step=2.  That page will check that the cooke exists (despite the
+  // fact that we've disabled third-party cookies) and alert('success:') or
+  // alert('failure:'), as appropriate.  Finally, the page will
+  // alert('finish');
+  iframe.src = innerPage;
+  document.body.appendChild(iframe);
+}
+
+// Disable third-party cookies for this test.
+addEventListener('testready', function() {
+  SpecialPowers.pushPrefEnv({'set': [['network.cookie.cookieBehavior', 1]]}, runTest);
+});