Add a very basic PIN UI implementation that is shared between lock and settings.

chrome/browser/resources/settings/people_page/people_page.js

 // Copyright 2015 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
  * 'settings-people-page' is the settings page containing sign-in settings.
  *
  * Example:
  *
@@ skipping 45 matching lines @@
 
     /** @private {!settings.SyncBrowserProxyImpl} */
     syncBrowserProxy_: {
       type: Object,
       value: function() {
         return settings.SyncBrowserProxyImpl.getInstance();
       },
     },
 
 <if expr="chromeos">
+    /**
+     * True if Pin Unlock is allowed on this machine.
+     */
+    pinUnlockAllowed_: {
+      type: Boolean,
+      value: function() {
+        /* TODO(jdufault): Return a real value via quickUnlockPrivate API. */
+        return false;
+      },
+      readOnly: true,
+    },
+
     /** @private {!settings.EasyUnlockBrowserProxyImpl} */
     easyUnlockBrowserProxy_: {
       type: Object,
       value: function() {
         return settings.EasyUnlockBrowserProxyImpl.getInstance();
       },
     },
 
     /**
      * True if Easy Unlock is allowed on this machine.
@@ skipping 102 matching lines @@
 
 <if expr="not chromeos">
   /** @private */
   onProfileNameTap_: function() {
     this.$.pages.setSubpageChain(['manageProfile']);
   },
 </if>
 
   /** @private */
   onActivityControlsTap_: function() {
     this.syncBrowserProxy_.openActivityControlsUrl();

[tommycli, 2016/05/06 23:54:18]

This will break the closure compiler since this method doesn't exist on the sync
browser proxy, i think.

[jdufault, 2016/05/10 18:45:23]

Rebase change.

   },
 
   /** @private */
   onSigninTap_: function() {
     this.syncBrowserProxy_.startSignIn();
   },
 
   /** @private */
   onDisconnectTap_: function() {
     this.$.disconnectDialog.open();
@@ skipping 44 matching lines @@
 
   /**
    * @private
    * @return {boolean}
    */
   isAdvancedSyncSettingsVisible_: function(syncStatus) {
     return syncStatus && syncStatus.signedIn && !syncStatus.managed &&
            syncStatus.syncSystemEnabled;
   },
 });