Enable profile switching for standalone App Launcher via the Settings App.

chrome/browser/resources/options/options_page.js

 // Copyright (c) 2012 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.
 
 cr.define('options', function() {
   /////////////////////////////////////////////////////////////////////////////
   // OptionsPage class:
 
   /**
    * Base class for options page.
@@ skipping 700 matching lines @@
   OptionsPage.setPepperFlashSettingsEnabled = function(enabled) {
     if (enabled) {
       document.documentElement.setAttribute(
           'enablePepperFlashSettings', '');
     } else {
       document.documentElement.removeAttribute(
           'enablePepperFlashSettings');
     }
   };
 
+  OptionsPage.setIsSettingsApp = function() {
+    document.documentElement.classList.add('settings-app');
+  };
+
+  OptionsPage.isSettingsApp = function() {
+    return document.documentElement.classList.contains('settings-app');
+  };
+
   OptionsPage.prototype = {
     __proto__: cr.EventTarget.prototype,
 
     /**
      * The parent page of this option page, or null for top-level pages.
      * @type {OptionsPage}
      */
     parentPage: null,
 
     /**
@@ skipping 212 matching lines @@
     canShowPage: function() {
       return true;
     },
   };
 
   // Export
   return {
     OptionsPage: OptionsPage
   };
 });