Settings Router Refactor: Implement new Route class w/ test

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.
+
+cr.define('settings', function() {
+  /**
+   * Class for navigable routes. May only be instantiated within this file.
+   * @constructor
+   * @param {string} url
+   * @private
+   */
+  var Route = function(url) {
+    this.url = url;
+
+    /** @private {?settings.Route} */
+    this.parent_ = null;
+
+    // Below are all legacy properties to provide compatibility with the old
+    // routing system. TODO(tommycli): Remove once routing refactor complete.
+    this.page = '';
+    this.section = '';
+    /** @type {!Array<string>} */ this.subpage = [];
+    this.dialog = false;
+  };
+
+  Route.prototype = {
+    /**
+     * Returns a new Route instance that's a child of this route.
+     * @param {string} url
+     * @param {string=} opt_subpageName
+     * @return {!settings.Route}
+     * @private
+     */
+    createChild: function(url, opt_subpageName) {
+      var route = new Route(url);
+      route.parent_ = this;
+      route.page = this.page;
+      route.section = this.section;
+      route.subpage = this.subpage.slice();  // Shallow copy.
+
+      if (opt_subpageName)
+        route.subpage.push(opt_subpageName);
+
+      return route;
+    },
+
+    /**
+     * Returns a new Route instance that's a child dialog of this route.
+     * @param {string} url
+     * @return {!settings.Route}
+     * @private
+     */
+    createDialog: function(url) {
+      var route = this.createChild(url);
+      route.dialog = true;
+      return route;
+    },
+
+    /**
+     * Returns true if this route is a descendant of the parameter.
+     * @param {!settings.Route} route
+     * @return {boolean}
+     */
+    isDescendantOf: function(route) {
+      for (var parent = this.parent_; parent != null; parent = parent.parent_) {
+        if (route == parent)
+          return true;
+      }
+
+      return false;
+    },
+  };
+
+  return {
+    Route: Route,
+  };
+});