diff -r 000000000000 -r 6474c204b198 dom/browser-element/mochitest/browserElement_AppFramePermission.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/browser-element/mochitest/browserElement_AppFramePermission.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,35 @@
+/* Any copyright is dedicated to the public domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Bug 777384 - Test mozapp permission.
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+browserElementTestHelpers.setEnabledPref(true);
+browserElementTestHelpers.addPermission();
+
+SpecialPowers.setAllAppsLaunchable(true);
+
+function testAppElement(expectAnApp, callback) {
+  var iframe = document.createElement('iframe');
+  SpecialPowers.wrap(iframe).mozbrowser = true;
+  iframe.setAttribute('mozapp', 'http://example.org/manifest.webapp');
+  iframe.addEventListener('mozbrowsershowmodalprompt', function(e) {
+    is(e.detail.message == 'app', expectAnApp, e.detail.message);
+    SimpleTest.executeSoon(callback);
+  });
+  document.body.appendChild(iframe);
+  iframe.src = 'http://example.org/tests/dom/browser-element/mochitest/file_browserElement_AppFramePermission.html';
+}
+
+function runTest() {
+  SpecialPowers.addPermission("embed-apps", true, document);
+  testAppElement(true, function() {
+    SpecialPowers.removePermission("embed-apps", document);
+    testAppElement(false, function() {
+      SimpleTest.finish();
+    });
+  });
+}
+
+addEventListener('testready', runTest);