[MD settings] fix typo in comment

chrome/browser/resources/settings/site_settings/site_settings_prefs_browser_proxy.js

 // Copyright 2016 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.
 
 /**
  * @fileoverview A helper object used from the "Site Settings" section to
  * interact with the content settings prefs.
  */
 
 /**
- * The handler will send a police source that is similar, but not exactly the
+ * The handler will send a policy source that is similar, but not exactly the
  * same as a ControlledBy value. If the ContentSettingProvider is omitted it
  * should be treated as 'default'.
  * @enum {string}
  */
 var ContentSettingProvider = {
   EXTENSION: 'extension',
   PREFERENCE: 'preference',
 };
 
 /**
@@ skipping 375 matching lines @@
     removeZoomLevel: function(host) {
       chrome.send('removeZoomLevel', [host]);
     },
   };
 
   return {
     SiteSettingsPrefsBrowserProxy: SiteSettingsPrefsBrowserProxy,
     SiteSettingsPrefsBrowserProxyImpl: SiteSettingsPrefsBrowserProxyImpl,
   };
 });