Fix Gmail Checker to update on reference fragment navigations, so the unread

chrome/common/extensions/docs/examples/extensions/gmail/background.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 animationFrames = 36;
 var animationSpeed = 10; // ms
 var canvas = document.getElementById('canvas');
 var loggedInImage = document.getElementById('logged_in');
 var canvasContext = canvas.getContext('2d');
 var pollIntervalMin = 5;  // 5 minutes
@@ skipping 306 matching lines @@
   chrome.runtime.onInstalled.addListener(onInit);
   chrome.alarms.onAlarm.addListener(onAlarm);
 }
 
 var filters = {
   // TODO(aa): Cannot use urlPrefix because all the url fields lack the protocol
   // part. See crbug.com/140238.
   url: [{urlContains: getGmailUrl().replace(/^https?\:\/\//, '')}]
 };
 
-chrome.webNavigation.onDOMContentLoaded.addListener(function(changeInfo) {
-  if (changeInfo.url && isGmailUrl(changeInfo.url)) {
-    console.log('Recognized Gmail navigation to: ' + changeInfo.url + '.' +
+function onNavigate(details) {
+  if (details.url && isGmailUrl(details.url)) {
+    console.log('Recognized Gmail navigation to: ' + details.url + '.' +
                 'Refreshing count...');
     startRequest({scheduleRequest:false, showLoadingAnimation:false});
   }
-}, filters);
+}
+if (chrome.webNavigation && chrome.webNavigation.onDOMContentLoaded &&
+    chrome.webNavigation.onReferenceFragmentUpdated) {
+  chrome.webNavigation.onDOMContentLoaded.addListener(onNavigate, filters);
+  chrome.webNavigation.onReferenceFragmentUpdated.addListener(
+      onNavigate, filters);
+} else {
+  chrome.tabs.onUpdated.addListener(function(_, details) {
+    onNavigate(details);
+  });
+}
 
 chrome.browserAction.onClicked.addListener(goToInbox);
 
 // This hack is needed because Chrome 22 does not persist browserAction icon
 // state, and also doesn't expose onStartup. So the icon always starts out in
 // wrong state. We don't actually need onStartup, we just use it as a clue
 // that we're in a version of Chrome that has this problem.
 if (chrome.runtime && !chrome.runtime.onStartup) {
   chrome.windows.onCreated.addListener(function() {
     console.log('Window created... updating icon.');
     updateIcon();
   });
 }