Take notification API out of experimental.

chrome/renderer/resources/extensions/notifications_custom_bindings.js

 // Copyright 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.
 
-// Custom bindings for the notification API.
+// Custom bindings for the chrome.notifications API.
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 var sendRequest = require('sendRequest').sendRequest;
 var imageUtil = require('imageUtil');
 var lastError = require('lastError');
 
 function url_getter(context, key) {
   var f = function() {
     return this[key];
   };
@@ skipping 95 matching lines @@
       }
       lastError.set('Unable to download all specified images.');
       failure_function(callback, id);
     });
   };
 }
 
 var handleCreate = genHandle(function(callback, id) { callback(id); });
 var handleUpdate = genHandle(function(callback, id) { callback(false); });
 
-var experimentalNotificationCustomHook = function(bindingsAPI, extensionId) {
+var notificationsCustomHook = function(bindingsAPI, extensionId) {
   var apiFunctions = bindingsAPI.apiFunctions;
   apiFunctions.setHandleRequest('create', handleCreate);
   apiFunctions.setHandleRequest('update', handleCreate);
 };
 
-chromeHidden.registerCustomHook('experimental.notification',
-                                experimentalNotificationCustomHook);
+chromeHidden.registerCustomHook('notifications', notificationsCustomHook);