Enable <adview> tag for packaged apps.

chrome/test/data/extensions/platform_apps/ad_view/load_event/chrometest.js

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+chrome.test.getConfig(function(config) {
+  var guestURL = 'http://localhost:' + config.testServer.port +
+      '/files/extensions/platform_apps/ad_view/ad_network/testsdk.html';
+  var adview = document.getElementsByTagName("adview")[0];
+
+  adview.addEventListener("loadcommit", function() {
+    chrome.test.sendMessage('guest-loaded');
+  })
+
+  adview.setAttribute("src", guestURL);
+});