Add the authenticate screen for the quick unlock settings.

chrome/browser/resources/settings/people_page/quick_unlock_routing_behavior.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.
+
+/** @enum {string} */
+var QuickUnlockScreen = {
+  AUTHENTICATE: 'quick-unlock-authenticate',
+  CHOOSE_METHOD: 'quick-unlock-choose-method',
+  SETUP_PIN: 'quick-unlock-setup-pin'
+};
+
+/** @polymerBehavior */
+var QuickUnlockRoutingBehavior = {
+  properties: {
+    currentRoute: {
+      type: Object,
+      notify: true,
+    }
+  },
+
+  /**
+   * Returns true if the given screen is active.
+   * @param {!QuickUnlockScreen} screen
+   * @return {!boolean}
+   */
+  isScreenActive: function(screen) {
+    var subpage = this.currentRoute.subpage;
+    return subpage.length > 0 && subpage[subpage.length - 1] == screen;
+  },
+};