Update references to the extension messaging APIs to point to the "runtime"

chrome/test/data/panels/context_menu2/test.js

 // Copyright (c) 2012 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.
 
 function onclick(info) {
   chrome.test.sendMessage("ow, don't do that!");
 }
 
 chrome.contextMenus.create({"title":"Extension Item Bogey",
                             "onclick": onclick}, function() {
-  if (!chrome.extension.lastError) {
+  if (!chrome.runtime.lastError) {
     chrome.test.sendMessage("created bogey item");
   }
 });