This adds the onNetworkChanged event to networkingPrivate

chrome/test/data/extensions/api_test/networking/test.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.
 
 var callbackPass = chrome.test.callbackPass;
 var callbackFail = chrome.test.callbackFail;
 var assertTrue = chrome.test.assertTrue;
 var assertEq = chrome.test.assertEq;
 
 chrome.test.runTests([
@@ skipping 62 matching lines @@
   function getProperties() {
     chrome.networkingPrivate.getProperties(
         "stub_wifi2",
         callbackPass(function(result) {
           assertTrue(!!result);
           assertEq("wifi2_PSK", result.Name);
           assertEq("NotConnected", result.ConnectionState);
           assertEq("WiFi", result.Type);
         }));
   },
+  function propertiesChangeEvent() {
+    var done = chrome.test.callbackAdded();
+    chrome.networkingPrivate.onNetworkChanged.addListener(
+        function (properties) {
+          assertEq(
+            [
+              {
+                "ConnectionState": "Connected",
+                "GUID": "stub_ethernet",
+                "Name": "eth0",
+                "Type": "Ethernet"
+              },
+              {
+                "ConnectionState": "Connecting",
+                "GUID": "stub_wifi1",
+                "Name": "wifi1",
+                "Type": "WiFi"
+              },
+              {
+                "ConnectionState": "NotConnected",
+                "GUID": "stub_wifi2",
+                "Name": "wifi2_PSK",
+                "Type": "WiFi"
+              },
+              {
+                "ConnectionState": "NotConnected",
+                "GUID": "stub_cellular1",
+                "Name": "cellular1",
+                "Type": "Cellular"
+              }
+            ], properties);
+          done();
+        });
+      chrome.networkingPrivate.startConnect("stub_wifi1",
+                                            callbackPass(function() {}));
+  },
   function startConnect() {
     chrome.networkingPrivate.startConnect("stub_wifi2",
                                           callbackPass(function() {}));
   },
   function startDisconnect() {
     chrome.networkingPrivate.startDisconnect("stub_wifi2",
                                              callbackPass(function() {}));
   },
   function startConnectNonexistent() {
     // Make sure we get an error when we try to connect to a nonexistent
     // network.
     chrome.networkingPrivate.startConnect(
       "nonexistent_path",
       callbackFail("Error.InvalidService", function() {}));
   }
 ]);