Site Settings: Give each category its own route.

chrome/browser/resources/settings/site_settings/site_list.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
  * 'settings-site-list' shows a list of Allowed and Blocked sites for a given
  * category.
  *
  * Example:
@@ skipping 82 matching lines @@
         return {
           allowAction: loadTimeData.getString('siteSettingsActionAllow'),
           blockAction: loadTimeData.getString('siteSettingsActionBlock'),
           resetAction: loadTimeData.getString('siteSettingsActionReset'),
         };
       },
     },
   },
 
   observers: [
-    'onCategoryChanged_(prefs.profile.content_settings.exceptions.*, category)',
+    'onCategoryChanged_(prefs.profile.content_settings.exceptions.*, ' +
+        'category, categorySubtype)',
   ],
 
   ready: function() {
     CrSettingsPrefs.initialized.then(function() {
       this.initialize_();
     }.bind(this));
   },
 
   /**
    * One-time initialization routines for this class.
@@ skipping 151 matching lines @@
    * Returns the icon to use for a given site.
    * @param {string} url The url of the site to fetch the icon for.
    * @private
    */
   computeSiteIcon_: function(url) {
     // TODO(finnur): For now, we're returning a placeholder image for each site
     // but the actual favicon for each site will need to be returned.
     return 'communication:message';
   },
 });