Site Settings Desktop: Flesh out controlled exceptions a little more.

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

 // Copyright 2015 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 Behavior common to Site Settings classes.
  */
 
 /** @polymerBehavior */
 var SiteSettingsBehaviorImpl = {
@@ skipping 400 matching lines @@
     if (embeddingOrigin == '') {
       if (category != settings.ContentSettingsTypes.GEOLOCATION)
         return '';
       return loadTimeData.getStringF('embeddedOnHost', '*');
     }
     return loadTimeData.getStringF(
         'embeddedOnHost', this.sanitizePort(embeddingOrigin));
   },
 
   /**
+   * Returns true if this exception is controlled by, for example, a policy or
+   * set by an extension.
+   * @param {string} source The source controlling the extension
+   * @return {boolean} Whether it is being controlled.
+   * @protected
+   */
+  isExceptionControlled_: function(source) {
+    return source != undefined && source != 'preference';
+  },
+
+  /**
    * Returns the icon to use for a given site.
    * @param {string} site The url of the site to fetch the icon for.
    * @return {string} The background-image style with the favicon.
    * @private
    */
   computeSiteIcon: function(site) {
     var url = this.ensureUrlHasScheme(site);
     return 'background-image: ' + cr.icon.getFavicon(url);
   },
 
@@ skipping 56 matching lines @@
       incognito: exception.incognito,
       setting: exception.setting,
       source: exception.source,
     };
   },
 
 };
 
 /** @polymerBehavior */
 var SiteSettingsBehavior = [SiteSettingsBehaviorImpl];