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 notifications API.
 
-var binding = require('binding').Binding.create('experimental.notification');
+var binding = require('binding').Binding.create('notifications');
 
 var sendRequest = require('sendRequest').sendRequest;
 var imageUtil = require('imageUtil');
 var lastError = require('lastError');
 var json = require('json');
 
 function url_getter(context, key) {
   var f = function() {
     return this[key];
   };
@@ skipping 98 matching lines @@
       // don't know where that is.
       lastError.run('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);
 };
 
-binding.registerCustomHook(experimentalNotificationCustomHook);
+binding.registerCustomHook(notificationsCustomHook);
 
 exports.binding = binding.generate();