MD Settings: remove unsupported routes from guest-mode.

chrome/browser/resources/settings/route.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.
 
+/**
+ * Specifies all possible routes in settings.
+ *
+ * @typedef {{
+ *   ABOUT: (undefined|!settings.Route),
+ *   ABOUT_ABOUT: (undefined|!settings.Route),
+ *   ACCESSIBILITY: (undefined|!settings.Route),
+ *   ACCOUNTS: (undefined|!settings.Route),
+ *   ADVANCED: (undefined|!settings.Route),
+ *   ANDROID_APPS: (undefined|!settings.Route),
+ *   ANDROID_APPS_DETAILS: (undefined|!settings.Route),
+ *   APPEARANCE: (undefined|!settings.Route),
+ *   AUTOFILL: (undefined|!settings.Route),
+ *   BASIC: (undefined|!settings.Route),
+ *   BLUETOOTH: (undefined|!settings.Route),
+ *   BLUETOOTH_DEVICES: (undefined|!settings.Route),
+ *   CERTIFICATES: (undefined|!settings.Route),
+ *   CHANGE_PICTURE: (undefined|!settings.Route),
+ *   CLEAR_BROWSER_DATA: (undefined|!settings.Route),
+ *   CLOUD_PRINTERS: (undefined|!settings.Route),
+ *   CUPS_PRINTER_DETAIL: (undefined|!settings.Route),
+ *   CUPS_PRINTERS: (undefined|!settings.Route),
+ *   DATETIME: (undefined|!settings.Route),
+ *   DEFAULT_BROWSER: (undefined|!settings.Route),
+ *   DETAILED_BUILD_INFO: (undefined|!settings.Route),
+ *   DEVICE: (undefined|!settings.Route),
+ *   DISPLAY: (undefined|!settings.Route),
+ *   DOWNLOADS: (undefined|!settings.Route),
+ *   EDIT_DICTIONARY: (undefined|!settings.Route),
+ *   FINGERPRINT: (undefined|!settings.Route),
+ *   FONTS: (undefined|!settings.Route),
+ *   IMPORT_DATA: (undefined|!settings.Route),
+ *   INPUT_METHODS: (undefined|!settings.Route),
+ *   INTERNET: (undefined|!settings.Route),
+ *   INTERNET_NETWORKS: (undefined|!settings.Route),
+ *   KEYBOARD: (undefined|!settings.Route),
+ *   KNOWN_NETWORKS: (undefined|!settings.Route),
+ *   LANGUAGES: (undefined|!settings.Route),
+ *   LOCK_SCREEN: (undefined|!settings.Route),
+ *   MANAGE_ACCESSIBILITY: (undefined|!settings.Route),
+ *   MANAGE_PASSWORDS: (undefined|!settings.Route),
+ *   MANAGE_PROFILE: (undefined|!settings.Route),
+ *   NETWORK_CONFIG: (undefined|!settings.Route),
+ *   NETWORK_DETAIL: (undefined|!settings.Route),
+ *   ON_STARTUP: (undefined|!settings.Route),
+ *   PASSWORDS: (undefined|!settings.Route),
+ *   PEOPLE: (undefined|!settings.Route),
+ *   POINTERS: (undefined|!settings.Route),
+ *   POWER: (undefined|!settings.Route),
+ *   PRINTING: (undefined|!settings.Route),
+ *   PRIVACY: (undefined|!settings.Route),
+ *   RESET: (undefined|!settings.Route),
+ *   RESET_DIALOG: (undefined|!settings.Route),
+ *   SEARCH: (undefined|!settings.Route),
+ *   SEARCH_ENGINES: (undefined|!settings.Route),
+ *   SIGN_OUT: (undefined|!settings.Route),
+ *   SITE_SETTINGS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_ADS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_ALL: (undefined|!settings.Route),
+ *   SITE_SETTINGS_AUTOMATIC_DOWNLOADS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_BACKGROUND_SYNC: (undefined|!settings.Route),
+ *   SITE_SETTINGS_CAMERA: (undefined|!settings.Route),
+ *   SITE_SETTINGS_COOKIES: (undefined|!settings.Route),
+ *   SITE_SETTINGS_DATA_DETAILS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_FLASH: (undefined|!settings.Route),
+ *   SITE_SETTINGS_HANDLERS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_IMAGES: (undefined|!settings.Route),
+ *   SITE_SETTINGS_JAVASCRIPT: (undefined|!settings.Route),
+ *   SITE_SETTINGS_LOCATION: (undefined|!settings.Route),
+ *   SITE_SETTINGS_MICROPHONE: (undefined|!settings.Route),
+ *   SITE_SETTINGS_MIDI_DEVICES: (undefined|!settings.Route),
+ *   SITE_SETTINGS_NOTIFICATIONS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_PDF_DOCUMENTS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_POPUPS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_PROTECTED_CONTENT: (undefined|!settings.Route),
+ *   SITE_SETTINGS_SITE_DETAILS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_UNSANDBOXED_PLUGINS: (undefined|!settings.Route),
+ *   SITE_SETTINGS_USB_DEVICES: (undefined|!settings.Route),
+ *   SITE_SETTINGS_ZOOM_LEVELS: (undefined|!settings.Route),
+ *   STORAGE: (undefined|!settings.Route),
+ *   STYLUS: (undefined|!settings.Route),
+ *   SYNC: (undefined|!settings.Route),
+ *   SYSTEM: (undefined|!settings.Route),
+ *   TRIGGERED_RESET_DIALOG: (undefined|!settings.Route),
+ * }}
+ */
+var SettingsRoutes;
+
 cr.define('settings', function() {
+
   /**
    * Class for navigable routes. May only be instantiated within this file.
-   * @constructor
-   * @param {string} path
-   * @private
    */
-  var Route = function(path) {
-    this.path = path;
+  class Route {
+    /** @param {string} path */
+    constructor(path) {
+      /** @type {string} */
+      this.path = path;
 
-    /** @type {?settings.Route} */
-    this.parent = null;
+      /** @type {?settings.Route} */
+      this.parent = null;
 
-    /** @type {number} */
-    this.depth = 0;
+      /** @type {number} */
+      this.depth = 0;
 
-    /**
-     * @type {boolean} Whether this route corresponds to a navigable
-     *     dialog. Those routes don't belong to a "section".
-     */
-    this.isNavigableDialog = false;
+      /**
+       * @type {boolean} Whether this route corresponds to a navigable
+       *     dialog. Those routes don't belong to a "section".
+       */
+      this.isNavigableDialog = false;
 
-    // Below are all legacy properties to provide compatibility with the old
-    // routing system.
+      // Below are all legacy properties to provide compatibility with the old
+      // routing system.
 
-    /** @type {string} */
-    this.section = '';
-  };
+      /** @type {string} */
+      this.section = '';
+    }
 
-  Route.prototype = {
     /**
      * Returns a new Route instance that's a child of this route.
      * @param {string} path Extends this route's path if it doesn't contain a
      *     leading slash.
      * @return {!settings.Route}
      * @private
      */
-    createChild: function(path) {
+    createChild(path) {
       assert(path);
 
       // |path| extends this route's path if it doesn't have a leading slash.
       // If it does have a leading slash, it's just set as the new route's URL.
       var newUrl = path[0] == '/' ? path : this.path + '/' + path;
 
       var route = new Route(newUrl);
       route.parent = this;
       route.section = this.section;
       route.depth = this.depth + 1;
 
       return route;
-    },
+    }
 
     /**
      * Returns a new Route instance that's a child section of this route.
      * TODO(tommycli): Remove once we've obsoleted the concept of sections.
      * @param {string} path
      * @param {string} section
      * @return {!settings.Route}
      * @private
      */
-    createSection: function(path, section) {
+    createSection(path, section) {
       var route = this.createChild(path);
       route.section = section;
       return route;
-    },
+    }
 
     /**
      * Returns true if this route matches or is an ancestor of the parameter.
      * @param {!settings.Route} route
      * @return {boolean}
      */
-    contains: function(route) {
+    contains(route) {
       for (var r = route; r != null; r = r.parent) {
         if (this == r)
           return true;
       }
       return false;
-    },
+    }
 
     /**
      * Returns true if this route is a subpage of a section.
      * @return {boolean}
      */
-    isSubpage: function() {
+    isSubpage() {
       return !!this.parent && !!this.section &&
           this.parent.section == this.section;
-    },
+    }
+  }
+
+  /**
+   * Computes and return all available routes based on settings.pageVisibility.
+   * @return {!SettingsRoutes}
+   */
+  var computeAvailableRoutes = function() {
+    var pageVisibility = settings.pageVisibility || {};
+
+    /** @type {!SettingsRoutes} */
+    var r = {};
+
+    // Root pages.
+    r.BASIC = new Route('/');
+    r.ABOUT = new Route('/help');
+
+    // Navigable dialogs. These are the only non-section children of root
+    // pages. These are disfavored. If we add anymore, we should add explicit
+    // support.
+    r.IMPORT_DATA = r.BASIC.createChild('/importData');
+    r.IMPORT_DATA.isNavigableDialog = true;
+    r.SIGN_OUT = r.BASIC.createChild('/signOut');
+    r.SIGN_OUT.isNavigableDialog = true;
+
+    // <if expr="chromeos">
+    r.INTERNET = r.BASIC.createSection('/internet', 'internet');
+    r.INTERNET_NETWORKS = r.INTERNET.createChild('/networks');
+    r.NETWORK_CONFIG = r.INTERNET.createChild('/networkConfig');
+    r.NETWORK_DETAIL = r.INTERNET.createChild('/networkDetail');
+    r.KNOWN_NETWORKS = r.INTERNET.createChild('/knownNetworks');
+    r.BLUETOOTH = r.BASIC.createSection('/bluetooth', 'bluetooth');
+    r.BLUETOOTH_DEVICES = r.BLUETOOTH.createChild('/bluetoothDevices');
+    // </if>
+
+    if (pageVisibility.appearance !== false) {
+      r.APPEARANCE = r.BASIC.createSection('/appearance', 'appearance');
+      r.FONTS = r.APPEARANCE.createChild('/fonts');
+    }
+
+    if (pageVisibility.defaultBrowser !== false) {
+      r.DEFAULT_BROWSER =
+          r.BASIC.createSection('/defaultBrowser', 'defaultBrowser');
+    }
+
+    r.SEARCH = r.BASIC.createSection('/search', 'search');
+    r.SEARCH_ENGINES = r.SEARCH.createChild('/searchEngines');
+
+    // <if expr="chromeos">
+    r.ANDROID_APPS = r.BASIC.createSection('/androidApps', 'androidApps');
+    r.ANDROID_APPS_DETAILS = r.ANDROID_APPS.createChild('/androidApps/details');
+    // </if>
+
+    if (pageVisibility.onStartup !== false) {
+      r.ON_STARTUP = r.BASIC.createSection('/onStartup', 'onStartup');
+    }
+
+    if (pageVisibility.people !== false) {
+      r.PEOPLE = r.BASIC.createSection('/people', 'people');
+      r.SYNC = r.PEOPLE.createChild('/syncSetup');
+      // <if expr="not chromeos">
+      r.MANAGE_PROFILE = r.PEOPLE.createChild('/manageProfile');
+      // </if>
+      // <if expr="chromeos">
+      r.CHANGE_PICTURE = r.PEOPLE.createChild('/changePicture');
+      r.ACCOUNTS = r.PEOPLE.createChild('/accounts');
+      r.LOCK_SCREEN = r.PEOPLE.createChild('/lockScreen');
+      r.FINGERPRINT = r.LOCK_SCREEN.createChild('/lockScreen/fingerprint');
+      // </if>
+    }
+
+    // <if expr="chromeos">
+    r.DEVICE = r.BASIC.createSection('/device', 'device');
+    r.POINTERS = r.DEVICE.createChild('/pointer-overlay');
+    r.KEYBOARD = r.DEVICE.createChild('/keyboard-overlay');
+    r.STYLUS = r.DEVICE.createChild('/stylus');
+    r.DISPLAY = r.DEVICE.createChild('/display');
+    r.STORAGE = r.DEVICE.createChild('/storage');
+    r.POWER = r.DEVICE.createChild('/power');
+    // </if>
+
+    // Advacned Routes
+    if (pageVisibility.advancedSettings !== false) {
+      r.ADVANCED = new Route('/advanced');
+
+      r.CLEAR_BROWSER_DATA = r.ADVANCED.createChild('/clearBrowserData');
+      r.CLEAR_BROWSER_DATA.isNavigableDialog = true;
+
+      if (pageVisibility.privacy !== false) {
+        r.PRIVACY = r.ADVANCED.createSection('/privacy', 'privacy');
+        r.CERTIFICATES = r.PRIVACY.createChild('/certificates');
+        r.SITE_SETTINGS = r.PRIVACY.createChild('/content');
+      }
+
+      if (loadTimeData.getBoolean('enableSiteSettings')) {
+        r.SITE_SETTINGS_ALL = r.SITE_SETTINGS.createChild('all');
+        r.SITE_SETTINGS_SITE_DETAILS =
+            r.SITE_SETTINGS_ALL.createChild('/content/siteDetails');
+      } else if (loadTimeData.getBoolean('enableSiteDetails')) {
+        // When there is no "All Sites", pressing 'back' from "Site Details"
+        // should return to "Content Settings". This should only occur when
+        // |kSiteSettings| is off and |kSiteDetails| is on.
+        r.SITE_SETTINGS_SITE_DETAILS =
+            r.SITE_SETTINGS.createChild('/content/siteDetails');
+      }
+
+      r.SITE_SETTINGS_HANDLERS = r.SITE_SETTINGS.createChild('/handlers');
+
+      // TODO(tommycli): Find a way to refactor these repetitive category
+      // routes.
+      r.SITE_SETTINGS_ADS = r.SITE_SETTINGS.createChild('ads');
+      r.SITE_SETTINGS_AUTOMATIC_DOWNLOADS =
+          r.SITE_SETTINGS.createChild('automaticDownloads');
+      r.SITE_SETTINGS_BACKGROUND_SYNC =
+          r.SITE_SETTINGS.createChild('backgroundSync');
+      r.SITE_SETTINGS_CAMERA = r.SITE_SETTINGS.createChild('camera');
+      r.SITE_SETTINGS_COOKIES = r.SITE_SETTINGS.createChild('cookies');
+      r.SITE_SETTINGS_DATA_DETAILS =
+          r.SITE_SETTINGS_COOKIES.createChild('/cookies/detail');
+      r.SITE_SETTINGS_IMAGES = r.SITE_SETTINGS.createChild('images');
+      r.SITE_SETTINGS_JAVASCRIPT = r.SITE_SETTINGS.createChild('javascript');
+      r.SITE_SETTINGS_LOCATION = r.SITE_SETTINGS.createChild('location');
+      r.SITE_SETTINGS_MICROPHONE = r.SITE_SETTINGS.createChild('microphone');
+      r.SITE_SETTINGS_NOTIFICATIONS =
+          r.SITE_SETTINGS.createChild('notifications');
+      r.SITE_SETTINGS_FLASH = r.SITE_SETTINGS.createChild('flash');
+      r.SITE_SETTINGS_POPUPS = r.SITE_SETTINGS.createChild('popups');
+      r.SITE_SETTINGS_UNSANDBOXED_PLUGINS =
+          r.SITE_SETTINGS.createChild('unsandboxedPlugins');
+      r.SITE_SETTINGS_MIDI_DEVICES = r.SITE_SETTINGS.createChild('midiDevices');
+      r.SITE_SETTINGS_USB_DEVICES = r.SITE_SETTINGS.createChild('usbDevices');
+      r.SITE_SETTINGS_ZOOM_LEVELS = r.SITE_SETTINGS.createChild('zoomLevels');
+      r.SITE_SETTINGS_PDF_DOCUMENTS =
+          r.SITE_SETTINGS.createChild('pdfDocuments');
+      r.SITE_SETTINGS_PROTECTED_CONTENT =
+          r.SITE_SETTINGS.createChild('protectedContent');
+
+      // <if expr="chromeos">
+      if (pageVisibility.dateTime !== false) {
+        r.DATETIME = r.ADVANCED.createSection('/dateTime', 'dateTime');
+      }
+      // </if>
+
+      if (pageVisibility.passwordsAndForms !== false) {
+        r.PASSWORDS =
+            r.ADVANCED.createSection('/passwordsAndForms', 'passwordsAndForms');
+        r.AUTOFILL = r.PASSWORDS.createChild('/autofill');
+        r.MANAGE_PASSWORDS = r.PASSWORDS.createChild('/passwords');
+      }
+
+      r.LANGUAGES = r.ADVANCED.createSection('/languages', 'languages');
+      // <if expr="chromeos">
+      r.INPUT_METHODS = r.LANGUAGES.createChild('/inputMethods');
+      // </if>
+      // <if expr="not is_macosx">
+      r.EDIT_DICTIONARY = r.LANGUAGES.createChild('/editDictionary');
+      // </if>
+
+      if (pageVisibility.downloads !== false) {
+        r.DOWNLOADS = r.ADVANCED.createSection('/downloads', 'downloads');
+      }
+
+      r.PRINTING = r.ADVANCED.createSection('/printing', 'printing');
+      r.CLOUD_PRINTERS = r.PRINTING.createChild('/cloudPrinters');
+      // <if expr="chromeos">
+      r.CUPS_PRINTERS = r.PRINTING.createChild('/cupsPrinters');
+      r.CUPS_PRINTER_DETAIL =
+          r.CUPS_PRINTERS.createChild('/cupsPrinterDetails');
+      // </if>
+
+      r.ACCESSIBILITY = r.ADVANCED.createSection('/accessibility', 'a11y');
+      // <if expr="chromeos">
+      r.MANAGE_ACCESSIBILITY =
+          r.ACCESSIBILITY.createChild('/manageAccessibility');
+      // </if>
+
+      r.SYSTEM = r.ADVANCED.createSection('/system', 'system');
+
+      if (pageVisibility.reset !== false) {
+        r.RESET = r.ADVANCED.createSection('/reset', 'reset');
+        r.RESET_DIALOG = r.ADVANCED.createChild('/resetProfileSettings');
+        r.RESET_DIALOG.isNavigableDialog = true;
+        r.TRIGGERED_RESET_DIALOG =
+            r.ADVANCED.createChild('/triggeredResetProfileSettings');
+        r.TRIGGERED_RESET_DIALOG.isNavigableDialog = true;
+      }
+    }
+
+    // <if expr="chromeos">
+    // "About" is the only section in About, but we still need to create the
+    // route in order to show the subpage on Chrome OS.
+    r.ABOUT_ABOUT = r.ABOUT.createSection('/help/about', 'about');
+    r.DETAILED_BUILD_INFO = r.ABOUT_ABOUT.createChild('/help/details');
+    // </if>
+
+    return r;
   };
 
-  // Abbreviated variable for easier definitions.
-  var r = Route;
-
-  // Root pages.
-  r.BASIC = new Route('/');
-  r.ADVANCED = new Route('/advanced');
-  r.ABOUT = new Route('/help');
-
-  // Navigable dialogs. These are the only non-section children of root pages.
-  // These are disfavored. If we add anymore, we should add explicit support.
-  r.IMPORT_DATA = r.BASIC.createChild('/importData');
-  r.IMPORT_DATA.isNavigableDialog = true;
-  r.SIGN_OUT = r.BASIC.createChild('/signOut');
-  r.SIGN_OUT.isNavigableDialog = true;
-  r.CLEAR_BROWSER_DATA = r.ADVANCED.createChild('/clearBrowserData');
-  r.CLEAR_BROWSER_DATA.isNavigableDialog = true;
-  r.RESET_DIALOG = r.ADVANCED.createChild('/resetProfileSettings');
-  r.RESET_DIALOG.isNavigableDialog = true;
-  r.TRIGGERED_RESET_DIALOG =
-      r.ADVANCED.createChild('/triggeredResetProfileSettings');
-  r.TRIGGERED_RESET_DIALOG.isNavigableDialog = true;
-
-  // <if expr="chromeos">
-  r.INTERNET = r.BASIC.createSection('/internet', 'internet');
-  r.INTERNET_NETWORKS = r.INTERNET.createChild('/networks');
-  r.NETWORK_CONFIG = r.INTERNET.createChild('/networkConfig');
-  r.NETWORK_DETAIL = r.INTERNET.createChild('/networkDetail');
-  r.KNOWN_NETWORKS = r.INTERNET.createChild('/knownNetworks');
-  r.BLUETOOTH = r.BASIC.createSection('/bluetooth', 'bluetooth');
-  r.BLUETOOTH_DEVICES = r.BLUETOOTH.createChild('/bluetoothDevices');
-  // </if>
-
-  r.APPEARANCE = r.BASIC.createSection('/appearance', 'appearance');
-  r.FONTS = r.APPEARANCE.createChild('/fonts');
-
-  r.DEFAULT_BROWSER =
-      r.BASIC.createSection('/defaultBrowser', 'defaultBrowser');
-
-  r.SEARCH = r.BASIC.createSection('/search', 'search');
-  r.SEARCH_ENGINES = r.SEARCH.createChild('/searchEngines');
-
-  // <if expr="chromeos">
-  r.ANDROID_APPS = r.BASIC.createSection('/androidApps', 'androidApps');
-  r.ANDROID_APPS_DETAILS = r.ANDROID_APPS.createChild('/androidApps/details');
-  // </if>
-
-  r.ON_STARTUP = r.BASIC.createSection('/onStartup', 'onStartup');
-
-  r.PEOPLE = r.BASIC.createSection('/people', 'people');
-  r.SYNC = r.PEOPLE.createChild('/syncSetup');
-  // <if expr="not chromeos">
-  r.MANAGE_PROFILE = r.PEOPLE.createChild('/manageProfile');
-  // </if>
-  // <if expr="chromeos">
-  r.CHANGE_PICTURE = r.PEOPLE.createChild('/changePicture');
-  r.ACCOUNTS = r.PEOPLE.createChild('/accounts');
-  r.LOCK_SCREEN = r.PEOPLE.createChild('/lockScreen');
-  r.FINGERPRINT = r.LOCK_SCREEN.createChild('/lockScreen/fingerprint');
-
-  r.DEVICE = r.BASIC.createSection('/device', 'device');
-  r.POINTERS = r.DEVICE.createChild('/pointer-overlay');
-  r.KEYBOARD = r.DEVICE.createChild('/keyboard-overlay');
-  r.STYLUS = r.DEVICE.createChild('/stylus');
-  r.DISPLAY = r.DEVICE.createChild('/display');
-  r.STORAGE = r.DEVICE.createChild('/storage');
-  r.POWER = r.DEVICE.createChild('/power');
-  // </if>
-
-  r.PRIVACY = r.ADVANCED.createSection('/privacy', 'privacy');
-  r.CERTIFICATES = r.PRIVACY.createChild('/certificates');
-
-  r.SITE_SETTINGS = r.PRIVACY.createChild('/content');
-
-  if (loadTimeData.getBoolean('enableSiteSettings')) {
-    r.SITE_SETTINGS_ALL = r.SITE_SETTINGS.createChild('all');
-    r.SITE_SETTINGS_SITE_DETAILS =
-        r.SITE_SETTINGS_ALL.createChild('/content/siteDetails');
-  } else if (loadTimeData.getBoolean('enableSiteDetails')) {
-    // When there is no "All Sites", pressing 'back' from "Site Details" should
-    // return to "Content Settings". This should only occur when |kSiteSettings|
-    // is off and |kSiteDetails| is on.
-    r.SITE_SETTINGS_SITE_DETAILS =
-        r.SITE_SETTINGS.createChild('/content/siteDetails');
+  class Router {
+    constructor() {
+      /**
+       * List of available routes. This is populated taking into account current
+       * state (like guest mode).
+       * @private {!SettingsRoutes}
+       */
+      this.routes_ = computeAvailableRoutes();
+
+      /**
+       * The current active route. This updated is only by settings.navigateTo
+       * or settings.initializeRouteFromUrl.
+       * @type {!settings.Route}
+       */
+      this.currentRoute = /** @type {!settings.Route} */ (this.routes_.BASIC);
+
+      /**
+       * The current query parameters. This is updated only by
+       * settings.navigateTo or settings.initializeRouteFromUrl.
+       * @private {!URLSearchParams}
+       */
+      this.currentQueryParameters_ = new URLSearchParams();
+
+      /** @private {boolean} */
+      this.wasLastRouteChangePopstate_ = false;
+
+      /** @private {boolean}*/
+      this.initializeRouteFromUrlCalled_ = false;
+    }
+
+    /** @return {settings.Route} */
+    getRoute(routeName) {
+      return this.routes_[routeName];
+    }
+
+    /** @return {!SettingsRoutes} */
+    getRoutes() {
+      return this.routes_;
+    }
+
+    /**
+     * Helper function to set the current route and notify all observers.
+     * @param {!settings.Route} route
+     * @param {!URLSearchParams} queryParameters
+     * @param {boolean} isPopstate
+     */
+    setCurrentRoute(route, queryParameters, isPopstate) {
+      var oldRoute = this.currentRoute;
+      this.currentRoute = route;
+      this.currentQueryParameters_ = queryParameters;
+      this.wasLastRouteChangePopstate_ = isPopstate;
+      routeObservers.forEach(function(observer) {
+        observer.currentRouteChanged(this.currentRoute, oldRoute);
+      }.bind(this));
+    }
+
+    /** @return {!settings.Route} */
+    getCurrentRoute() {
+      return this.currentRoute;
+    }
+
+    /** @return {!URLSearchParams} */
+    getQueryParameters() {
+      return new URLSearchParams(
+          this.currentQueryParameters_);  // Defensive copy.
+    }
+
+    /** @return {boolean} */
+    lastRouteChangeWasPopstate() {
+      return this.wasLastRouteChangePopstate_;
+    }
+
+    /**
+     * @param {string} path
+     * @return {?settings.Route} The matching canonical route, or null if none
+     *     matches.
+     */
+    getRouteForPath(path) {
+      // Allow trailing slash in paths.
+      var canonicalPath = path.replace(CANONICAL_PATH_REGEX, '$1$2');
+
+      // TODO(tommycli): Use Object.values once Closure compilation supports it.
+      var matchingKey = Object.keys(this.routes_).find(function(key) {
+        return this.routes_[key].path == canonicalPath;
+      }.bind(this));
+
+      return !!matchingKey ? this.routes_[matchingKey] : null;
+    }
+
+    /**
+     * Navigates to a canonical route and pushes a new history entry.
+     * @param {!settings.Route} route
+     * @param {URLSearchParams=} opt_dynamicParameters Navigations to the same
+     *     URL parameters in a different order will still push to history.
+     * @param {boolean=} opt_removeSearch Whether to strip the 'search' URL
+     *     parameter during navigation. Defaults to false.
+     */
+    navigateTo(route, opt_dynamicParameters, opt_removeSearch) {
+      // The ADVANCED route only serves as a parent of subpages, and should not
+      // be possible to navigate to it directly.
+      if (route == this.routes_.ADVANCED)
+        route = /** @type {!settings.Route} */ (this.routes_.BASIC);
+
+      var params = opt_dynamicParameters || new URLSearchParams();
+      var removeSearch = !!opt_removeSearch;
+
+      var oldSearchParam = this.getQueryParameters().get('search') || '';
+      var newSearchParam = params.get('search') || '';
+
+      if (!removeSearch && oldSearchParam && !newSearchParam)
+        params.append('search', oldSearchParam);
+
+      var url = route.path;
+      var queryString = params.toString();
+      if (queryString)
+        url += '?' + queryString;
+
+      // History serializes the state, so we don't push the actual route object.
+      window.history.pushState(this.currentRoute.path, '', url);
+      this.setCurrentRoute(route, params, false);
+    }
+
+    /**
+     * Navigates to the previous route if it has an equal or lesser depth.
+     * If there is no previous route in history meeting those requirements,
+     * this navigates to the immediate parent. This will never exit Settings.
+     */
+    navigateToPreviousRoute() {
+      var previousRoute = window.history.state &&
+          assert(this.getRouteForPath(
+              /** @type {string} */ (window.history.state)));
+
+      if (previousRoute && previousRoute.depth <= this.currentRoute.depth)
+        window.history.back();
+      else
+        this.navigateTo(
+            this.currentRoute.parent ||
+            /** @type {!settings.Route} */ (this.routes_.BASIC));
+    }
+
+    /**
+     * Initialize the route and query params from the URL.
+     */
+    initializeRouteFromUrl() {
+      assert(!this.initializeRouteFromUrlCalled_);
+      this.initializeRouteFromUrlCalled_ = true;
+
+      var route = this.getRouteForPath(window.location.pathname);
+      // Never allow direct navigation to ADVANCED.
+      if (route && route != this.routes_.ADVANCED) {
+        this.currentRoute = route;
+        this.currentQueryParameters_ =
+            new URLSearchParams(window.location.search);
+      } else {
+        window.history.replaceState(undefined, '', this.routes_.BASIC.path);
+      }
+    }
+
+    resetRouteForTesting() {
+      this.initializeRouteFromUrlCalled_ = false;
+      this.wasLastRouteChangePopstate_ = false;
+      this.currentRoute = /** @type {!settings.Route} */ (this.routes_.BASIC);
+      this.currentQueryParameters_ = new URLSearchParams();
+    }
   }
 
-  r.SITE_SETTINGS_HANDLERS = r.SITE_SETTINGS.createChild('/handlers');
-
-  // TODO(tommycli): Find a way to refactor these repetitive category routes.
-  r.SITE_SETTINGS_ADS = r.SITE_SETTINGS.createChild('ads');
-  r.SITE_SETTINGS_AUTOMATIC_DOWNLOADS =
-      r.SITE_SETTINGS.createChild('automaticDownloads');
-  r.SITE_SETTINGS_BACKGROUND_SYNC =
-      r.SITE_SETTINGS.createChild('backgroundSync');
-  r.SITE_SETTINGS_CAMERA = r.SITE_SETTINGS.createChild('camera');
-  r.SITE_SETTINGS_COOKIES = r.SITE_SETTINGS.createChild('cookies');
-  r.SITE_SETTINGS_DATA_DETAILS =
-      r.SITE_SETTINGS_COOKIES.createChild('/cookies/detail');
-  r.SITE_SETTINGS_IMAGES = r.SITE_SETTINGS.createChild('images');
-  r.SITE_SETTINGS_JAVASCRIPT = r.SITE_SETTINGS.createChild('javascript');
-  r.SITE_SETTINGS_LOCATION = r.SITE_SETTINGS.createChild('location');
-  r.SITE_SETTINGS_MICROPHONE = r.SITE_SETTINGS.createChild('microphone');
-  r.SITE_SETTINGS_NOTIFICATIONS = r.SITE_SETTINGS.createChild('notifications');
-  r.SITE_SETTINGS_FLASH = r.SITE_SETTINGS.createChild('flash');
-  r.SITE_SETTINGS_POPUPS = r.SITE_SETTINGS.createChild('popups');
-  r.SITE_SETTINGS_UNSANDBOXED_PLUGINS =
-      r.SITE_SETTINGS.createChild('unsandboxedPlugins');
-  r.SITE_SETTINGS_MIDI_DEVICES = r.SITE_SETTINGS.createChild('midiDevices');
-  r.SITE_SETTINGS_USB_DEVICES = r.SITE_SETTINGS.createChild('usbDevices');
-  r.SITE_SETTINGS_ZOOM_LEVELS = r.SITE_SETTINGS.createChild('zoomLevels');
-  r.SITE_SETTINGS_PDF_DOCUMENTS = r.SITE_SETTINGS.createChild('pdfDocuments');
-  r.SITE_SETTINGS_PROTECTED_CONTENT =
-      r.SITE_SETTINGS.createChild('protectedContent');
-
-  // <if expr="chromeos">
-  r.DATETIME = r.ADVANCED.createSection('/dateTime', 'dateTime');
-  // </if>
-
-  r.PASSWORDS =
-      r.ADVANCED.createSection('/passwordsAndForms', 'passwordsAndForms');
-  r.AUTOFILL = r.PASSWORDS.createChild('/autofill');
-  r.MANAGE_PASSWORDS = r.PASSWORDS.createChild('/passwords');
-
-  r.LANGUAGES = r.ADVANCED.createSection('/languages', 'languages');
-  // <if expr="chromeos">
-  r.INPUT_METHODS = r.LANGUAGES.createChild('/inputMethods');
-  // </if>
-  // <if expr="not is_macosx">
-  r.EDIT_DICTIONARY = r.LANGUAGES.createChild('/editDictionary');
-  // </if>
-
-  r.DOWNLOADS = r.ADVANCED.createSection('/downloads', 'downloads');
-
-  r.PRINTING = r.ADVANCED.createSection('/printing', 'printing');
-  r.CLOUD_PRINTERS = r.PRINTING.createChild('/cloudPrinters');
-  // <if expr="chromeos">
-  r.CUPS_PRINTERS = r.PRINTING.createChild('/cupsPrinters');
-  r.CUPS_PRINTER_DETAIL = r.CUPS_PRINTERS.createChild('/cupsPrinterDetails');
-  // </if>
-
-  r.ACCESSIBILITY = r.ADVANCED.createSection('/accessibility', 'a11y');
-  // <if expr="chromeos">
-  r.MANAGE_ACCESSIBILITY = r.ACCESSIBILITY.createChild('/manageAccessibility');
-  // </if>
-
-  r.SYSTEM = r.ADVANCED.createSection('/system', 'system');
-  r.RESET = r.ADVANCED.createSection('/reset', 'reset');
-
-  // <if expr="chromeos">
-  // "About" is the only section in About, but we still need to create the route
-  // in order to show the subpage on Chrome OS.
-  r.ABOUT_ABOUT = r.ABOUT.createSection('/help/about', 'about');
-  r.DETAILED_BUILD_INFO = r.ABOUT_ABOUT.createChild('/help/details');
-  // </if>
+  var routerInstance = new Router();
 
   var routeObservers = new Set();
 
   /** @polymerBehavior */
   var RouteObserverBehavior = {
     /** @override */
     attached: function() {
       assert(!routeObservers.has(this));
       routeObservers.add(this);
 
       // Emulating Polymer data bindings, the observer is called when the
       // element starts observing the route.
-      this.currentRouteChanged(currentRoute, undefined);
+      this.currentRouteChanged(routerInstance.currentRoute, undefined);
     },
 
     /** @override */
     detached: function() {
       assert(routeObservers.delete(this));
     },
 
     /**
      * @param {!settings.Route|undefined} opt_newRoute
      * @param {!settings.Route|undefined} opt_oldRoute
      * @abstract
      */
     currentRouteChanged: function(opt_newRoute, opt_oldRoute) {
       assertNotReached();
     },
   };
 
   /**
    * Regular expression that captures the leading slash, the content and the
    * trailing slash in three different groups.
    * @const {!RegExp}
    */
   var CANONICAL_PATH_REGEX = /(^\/)([\/-\w]+)(\/$)/;
 
-  /**
-   * @param {string} path
-   * @return {?settings.Route} The matching canonical route, or null if none
-   *     matches.
-   */
-  var getRouteForPath = function(path) {
-    // Allow trailing slash in paths.
-    var canonicalPath = path.replace(CANONICAL_PATH_REGEX, '$1$2');
-
-    // TODO(tommycli): Use Object.values once Closure compilation supports it.
-    var matchingKey = Object.keys(Route).find(function(key) {
-      return Route[key].path == canonicalPath;
-    });
-
-    return !!matchingKey ? Route[matchingKey] : null;
-  };
-
-  /**
-   * The current active route. This updated is only by settings.navigateTo or
-   * settings.initializeRouteFromUrl.
-   * @private {!settings.Route}
-   */
-  var currentRoute = Route.BASIC;
-
-  /**
-   * The current query parameters. This is updated only by settings.navigateTo
-   * or settings.initializeRouteFromUrl.
-   * @private {!URLSearchParams}
-   */
-  var currentQueryParameters = new URLSearchParams();
-
-  /** @private {boolean} */
-  var wasLastRouteChangePopstate = false;
-
-  /** @private */
-  var initializeRouteFromUrlCalled = false;
-
-  /**
-   * Initialize the route and query params from the URL.
-   */
-  var initializeRouteFromUrl = function() {
-    assert(!initializeRouteFromUrlCalled);
-    initializeRouteFromUrlCalled = true;
-
-    var route = getRouteForPath(window.location.pathname);
-    // Never allow direct navigation to ADVANCED.
-    if (route && route != Route.ADVANCED) {
-      currentRoute = route;
-      currentQueryParameters = new URLSearchParams(window.location.search);
-    } else {
-      window.history.replaceState(undefined, '', Route.BASIC.path);
-    }
-  };
-
-  function resetRouteForTesting() {
-    initializeRouteFromUrlCalled = false;
-    wasLastRouteChangePopstate = false;
-    currentRoute = Route.BASIC;
-    currentQueryParameters = new URLSearchParams();
-  }
-
-  /**
-   * Helper function to set the current route and notify all observers.
-   * @param {!settings.Route} route
-   * @param {!URLSearchParams} queryParameters
-   * @param {boolean} isPopstate
-   */
-  var setCurrentRoute = function(route, queryParameters, isPopstate) {
-    var oldRoute = currentRoute;
-    currentRoute = route;
-    currentQueryParameters = queryParameters;
-    wasLastRouteChangePopstate = isPopstate;
-    routeObservers.forEach(function(observer) {
-      observer.currentRouteChanged(currentRoute, oldRoute);
-    });
-  };
-
-  /** @return {!settings.Route} */
-  var getCurrentRoute = function() {
-    return currentRoute;
-  };
-
-  /** @return {!URLSearchParams} */
-  var getQueryParameters = function() {
-    return new URLSearchParams(currentQueryParameters);  // Defensive copy.
-  };
-
-  /** @return {boolean} */
-  var lastRouteChangeWasPopstate = function() {
-    return wasLastRouteChangePopstate;
-  };
-
-  /**
-   * Navigates to a canonical route and pushes a new history entry.
-   * @param {!settings.Route} route
-   * @param {URLSearchParams=} opt_dynamicParameters Navigations to the same
-   *     URL parameters in a different order will still push to history.
-   * @param {boolean=} opt_removeSearch Whether to strip the 'search' URL
-   *     parameter during navigation. Defaults to false.
-   */
-  var navigateTo = function(route, opt_dynamicParameters, opt_removeSearch) {
-    // The ADVANCED route only serves as a parent of subpages, and should not
-    // be possible to navigate to it directly.
-    if (route == settings.Route.ADVANCED)
-      route = settings.Route.BASIC;
-
-    var params = opt_dynamicParameters || new URLSearchParams();
-    var removeSearch = !!opt_removeSearch;
-
-    var oldSearchParam = getQueryParameters().get('search') || '';
-    var newSearchParam = params.get('search') || '';
-
-    if (!removeSearch && oldSearchParam && !newSearchParam)
-      params.append('search', oldSearchParam);
-
-    var url = route.path;
-    var queryString = params.toString();
-    if (queryString)
-      url += '?' + queryString;
-
-    // History serializes the state, so we don't push the actual route object.
-    window.history.pushState(currentRoute.path, '', url);
-    setCurrentRoute(route, params, false);
-  };
-
-  /**
-   * Navigates to the previous route if it has an equal or lesser depth.
-   * If there is no previous route in history meeting those requirements,
-   * this navigates to the immediate parent. This will never exit Settings.
-   */
-  var navigateToPreviousRoute = function() {
-    var previousRoute = window.history.state &&
-        assert(getRouteForPath(/** @type {string} */ (window.history.state)));
-
-    if (previousRoute && previousRoute.depth <= currentRoute.depth)
-      window.history.back();
-    else
-      navigateTo(currentRoute.parent || Route.BASIC);
-  };
-
   window.addEventListener('popstate', function(event) {
     // On pop state, do not push the state onto the window.history again.
-    setCurrentRoute(
-        getRouteForPath(window.location.pathname) || Route.BASIC,
+    routerInstance.setCurrentRoute(
+        /** @type {!settings.Route} */ (
+            routerInstance.getRouteForPath(window.location.pathname) ||
+            routerInstance.getRoutes().BASIC),
         new URLSearchParams(window.location.search), true);
   });
 
+  // TODO(scottchen): Change to 'get routes() {}' in export when we fix a bug in
+  // ChromePass that limits the syntax of what can be returned from cr.define().
+  var routes = routerInstance.getRoutes();
+
+  // TODO(scottchen): Stop exposing all those methods directly on settings.*,
+  // and instead update all clients to use the singleton instance directly
+  var getCurrentRoute = routerInstance.getCurrentRoute.bind(routerInstance);
+  var getRouteForPath = routerInstance.getRouteForPath.bind(routerInstance);
+  var initializeRouteFromUrl =
+      routerInstance.initializeRouteFromUrl.bind(routerInstance);
+  var resetRouteForTesting =
+      routerInstance.resetRouteForTesting.bind(routerInstance);
+  var getQueryParameters =
+      routerInstance.getQueryParameters.bind(routerInstance);
+  var lastRouteChangeWasPopstate =
+      routerInstance.lastRouteChangeWasPopstate.bind(routerInstance);
+  var navigateTo = routerInstance.navigateTo.bind(routerInstance);
+  var navigateToPreviousRoute =
+      routerInstance.navigateToPreviousRoute.bind(routerInstance);
+
   return {
-    Route: Route,
+    Route: Route,            // The class definition.
+    Router: Router,          // The class definition.

[stevenjb, 2017/07/10 18:01:25]

tiny nit: S/The class/Class/ for both of these since there is more than one
class?

[scottchen, 2017/07/10 20:54:35]

Acknowledged.

+    router: routerInstance,  // the singleton.
+    routes: routes,
     RouteObserverBehavior: RouteObserverBehavior,
     getRouteForPath: getRouteForPath,
     initializeRouteFromUrl: initializeRouteFromUrl,
     resetRouteForTesting: resetRouteForTesting,
     getCurrentRoute: getCurrentRoute,
     getQueryParameters: getQueryParameters,
     lastRouteChangeWasPopstate: lastRouteChangeWasPopstate,
     navigateTo: navigateTo,
     navigateToPreviousRoute: navigateToPreviousRoute,
   };
 });