Fix a typo in webview_custom_bindings.js

chrome/renderer/resources/extensions/webview_custom_bindings.js

 // Copyright 2014 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 binding for <webview> contextMenus API.
 // Note that this file mimics custom bindings for chrome.contextMenus API
 // which resides in context_menus_custom_bindings.js. The functions in this file
 // have an extra instanceId parameter in the beginning, which corresponds to the
 // id of the <webview>.
 //
@@ skipping 81 matching lines @@
   });
 
   apiFunctions.setCustomCallback('contextMenusUpdate',
                                  function(name, request, response) {
     if (chrome.runtime.lastError) {
       return;
     }
     var instanceId = request.args[0];
     var id = request.args[1];
     if (request.args[2].onclick) {
-      contextMenus.handlersForId(instanceId, id)[id] = request.args[2].onclick;
+      webviewContextMenus.handlersForId(instanceId, id)[id] =
+          request.args[2].onclick;
     }
   });
 
   apiFunctions.setCustomCallback('contextMenusRemove',
                                   function(name, request, response) {
     if (chrome.runtime.lastError) {
       return;
     }
     var instanceId = request.args[0];
     var id = request.args[1];
     delete webviewContextMenus.handlersForId(instanceId, id)[id];
   });
 
   apiFunctions.setCustomCallback('contextMenusRemoveAll',
                                  function(name, request, response) {
     if (chrome.runtime.lastError) {
       return;
     }
     var instanceId = request.args[0];
     webviewContextMenus.stringIdHandlers[instanceId] = {};
     webviewContextMenus.generatedIdHandlers[instanceId] = {};
   });
 
 });
 
 exports.WebView = binding.generate();