[MD settings] hide option for incognito on session only exceptions

chrome/browser/resources/settings/site_settings/add_site_dialog.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
  * 'add-site-dialog' provides a dialog to add exceptions for a given Content
  * Settings category.
  */
 Polymer({
   is: 'add-site-dialog',
 
   behaviors: [SiteSettingsBehavior, WebUIListenerBehavior],
 
   properties: {
     /**
      * What kind of setting, e.g. Location, Camera, Cookies, and so on.
      * @type {settings.ContentSettingsTypes}
      */
     category: String,
 
     /**
      * Whether this is about an Allow, Block, SessionOnly, or other.
      * @type {settings.PermissionValues}
      */
     contentSetting: String,
 
     /** @private */
-    isIncognitoActive_: Boolean,
+    showIncognitoSessionOnly_: Boolean,
 
     /**
      * The site to add an exception for.
      * @private
      */
     site_: String,
   },
 
   /** @override */
   attached: function() {
     assert(this.category);
     assert(this.contentSetting);
   },
 
   /**
    * Opens the dialog.
    * @param {string} type Whether this was launched from an Allow list or a
    *     Block list.
    */
   open: function(type) {
     this.addWebUIListener('onIncognitoStatusChanged', function(isActive) {
-      this.isIncognitoActive_ = isActive;
+      this.showIncognitoSessionOnly_ = isActive &&
+          this.contentSetting != settings.PermissionValues.SESSION_ONLY;
     }.bind(this));
     this.browserProxy.updateIncognitoStatus();
     this.$.dialog.showModal();
   },
 
   /**
    * Validates that the pattern entered is valid.
    * @private
    */
   validate_: function() {
@@ skipping 23 matching lines @@
    */
   onSubmit_: function() {
     if (this.$.add.disabled)
       return;  // Can happen when Enter is pressed.
     this.browserProxy.setCategoryPermissionForOrigin(
         this.site_, this.site_, this.category, this.contentSetting,
         this.$.incognito.checked);
     this.$.dialog.close();
   },
 });