Change the way json_schema.js is loaded. This is required so

chrome/renderer/resources/extension_process_bindings.js

 // Copyright (c) 2009 The chrome Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // -----------------------------------------------------------------------------
 // NOTE: If you change this file you need to touch renderer_resources.grd to
 // have your change take effect.
 // -----------------------------------------------------------------------------
 
 // This script contains privileged chrome extension related javascript APIs.
@@ skipping 15 matching lines @@
   var chromeHidden = GetChromeHidden();
 
   // Validate arguments.
   chromeHidden.validationTypes = [];
   chromeHidden.validate = function(args, schemas) {
     if (args.length > schemas.length)
       throw new Error("Too many arguments.");
 
     for (var i = 0; i < schemas.length; i++) {
       if (i in args && args[i] !== null && args[i] !== undefined) {
-        var validator = new chrome.JSONSchemaValidator();
+        var validator = new chromeHidden.JSONSchemaValidator();
         validator.addTypes(chromeHidden.validationTypes);
         validator.validate(args[i], schemas[i]);
         if (validator.errors.length == 0)
           continue;
 
         var message = "Invalid value for argument " + i + ". ";
         for (var i = 0, err; err = validator.errors[i]; i++) {
           if (err.path) {
             message += "Property '" + err.path + "': ";
           }
@@ skipping 230 matching lines @@
     apiFunctions["extension.getTabContentses"].handleRequest =
         function(windowId) {
       if (typeof(windowId) == "undefined")
         windowId = -1;
       return GetExtensionViews(windowId, "TAB");
     }
 
     setupPageActionEvents(extensionId);
   });
  })();