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

chrome/test/data/extensions/api_test/messaging/connect_panel/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.
 
 var panelWindowId = 0;
 
 chrome.test.runTests([
   function openPanelThatConnectsToExtension() {
-    chrome.test.listenOnce(chrome.extension.onConnect, function(port) {
+    chrome.test.listenOnce(chrome.runtime.onConnect, function(port) {
       chrome.test.assertEq(panelWindowId, port.sender.tab.windowId);
       chrome.test.assertTrue(port.sender.tab.id > 0);
     });
     chrome.windows.create(
         { 'url': chrome.extension.getURL('panel.html'), 'type': 'panel' },
         chrome.test.callbackPass(function(win) {
           chrome.test.assertEq('panel', win.type);
           panelWindowId = win.id;
         }));
   }
 ]);