Apply content-security-policy to the HTML options page. This is a

chrome/browser/resources/shared/js/chromeos/proxy_options.js

 // Copyright (c) 2011 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.
 
 cr.define('options', function() {
 
   var OptionsPage = options.OptionsPage;
   var Preferences = options.Preferences;
 
   /////////////////////////////////////////////////////////////////////////////
@@ skipping 170 matching lines @@
       }
     }
   };
 
   // Export
   return {
     ProxyOptions: ProxyOptions
   };
 
 });