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

chrome/test/data/extensions/api_test/incognito/split/background.js

 // Copyright (c) 2011 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.
 
 var pass = chrome.test.callbackPass;
 var assertEq = chrome.test.assertEq;
 var assertTrue = chrome.test.assertTrue;
 
 var win, tab;
 var inIncognitoContext = chrome.extension.inIncognitoContext;
@@ skipping 82 matching lines @@
 
       // Test that chrome.extension.inIncognitoContext is true for incognito
       // tabs.
       chrome.tabs.create({windowId: win.id, url: testUrl},
         pass(function(tab) {
           chrome.tabs.executeScript(tab.id,
             {code: 'chrome.extension.sendRequest({' +
                    '  inIncognitoContext: chrome.extension.inIncognitoContext' +
                    '});'},
             pass(function() {
-              assertEq(undefined, chrome.extension.lastError);
+              assertEq(undefined, chrome.runtime.lastError);
             }));
         }));
 
       var done = chrome.test.listenForever(chrome.extension.onRequest,
         function(request, sender, sendResponse) {
           assertEq(inIncognitoContext, request.inIncognitoContext);
           sendResponse();
           done();
         });
     },
@@ skipping 33 matching lines @@
 
     // Tests that we can set cookies in both processes.
     function setDocumentCookie() {
       document.cookie = "k=v";
       chrome.test.assertTrue(document.cookie.indexOf("k=v") != -1);
       chrome.test.succeed();
     }
   ]);
 
 });