Better support for patterns.

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 266 matching lines @@
           return loadTimeData.getString('siteSettingsDontShowImages');
         }
         return showRecommendation ?
             loadTimeData.getString('siteSettingsShowAllRecommended') :
             loadTimeData.getString('siteSettingsShowAll');
       default:
         assertNotReached();
         return '';
     }
   },
+
+  /**
+   * Ensures the URL has a scheme (assumes http if omitted).
+   * @param {string} url The URL with or without a scheme.
+   * @return {string} The URL with a scheme, or an empty string.
+   */
+  ensureUrlHasScheme: function(url) {
+    if (url.length == 0) return url;
+    return url.includes('://') ? url : 'http://' + url;
+  },
 };
 
 /** @polymerBehavior */
 var SiteSettingsBehavior = [SiteSettingsBehaviorImpl];