Remove support for the keygen tag

chrome/browser/resources/settings/site_settings/category_default_setting.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
  * 'category-default-setting' is the polymer element for showing a certain
  * category under Site Settings.
  */
 Polymer({
@@ skipping 46 matching lines @@
 
   /**
    * A handler for changing the default permission value for a content type.
    * @private
    */
   onChangePermissionControl_: function() {
     switch (this.category) {
       case settings.ContentSettingsTypes.BACKGROUND_SYNC:
       case settings.ContentSettingsTypes.IMAGES:
       case settings.ContentSettingsTypes.JAVASCRIPT:
-      case settings.ContentSettingsTypes.KEYGEN:
       case settings.ContentSettingsTypes.POPUPS:
       case settings.ContentSettingsTypes.PROTOCOL_HANDLERS:
         // "Allowed" vs "Blocked".
         this.browserProxy.setDefaultValueForContentType(
             this.category,
             this.categoryEnabled ?
                 settings.PermissionValues.ALLOW :
                 settings.PermissionValues.BLOCK);
         break;
       case settings.ContentSettingsTypes.AUTOMATIC_DOWNLOADS:
@@ skipping 69 matching lines @@
           } else if (
               this.category == settings.ContentSettingsTypes.COOKIES) {
             if (setting == settings.PermissionValues.ALLOW)
               this.subOptionEnabled_ = false;
             else if (setting == settings.PermissionValues.SESSION_ONLY)
               this.subOptionEnabled_ = true;
           }
         }.bind(this));
   },
 });