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

chrome/test/data/extensions/context_menus/separators/common.js

 // Copyright (c) 2010 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 create(title, type, parent, callback) {
   props = {};
   if (title) {
     props.title = title;
   }
   props.type = type;
 
   if (parent) {
     props.parentId = parent;
   }
 
   chrome.contextMenus.create(props, function() {
-    if (!chrome.extension.lastError && callback) {
+    if (!chrome.runtime.lastError && callback) {
       callback();
     }
   });
 }
 
 function createTestSet(parent, callback) {
   create("radio1", "radio", parent);
   create("radio2", "radio", parent);
   create("normal1", "normal", parent);
   create(null, "separator", parent);
   create("normal2", "normal", parent);
   create(null, "separator", parent);
   create("radio3", "radio", parent);
   create("radio4", "radio", parent);
   create(null, "separator", parent);
   create("normal3", "normal", parent, callback);
 }