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

ui/login/account_picker/user_pod_row.js

 // Copyright 2014 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 User pod row implementation.
  */
 
 cr.define('login', function() {
   /**
@@ skipping 714 matching lines @@
           this.handleRemoveCommandKeyDown_.bind(this));
       this.actionBoxMenuRemoveElement.addEventListener('blur',
           this.handleRemoveCommandBlur_.bind(this));
       this.actionBoxRemoveUserWarningButtonElement.addEventListener(
           'click',
           this.handleRemoveUserConfirmationClick_.bind(this));
         this.actionBoxRemoveUserWarningButtonElement.addEventListener(
             'keydown',
             this.handleRemoveUserConfirmationKeyDown_.bind(this));
 
+      var pinKeyboard = document.getElementById('pin-keyboard');
+      pinKeyboard.addEventListener('submit',
+          this.handlePinSubmitted_.bind(this));
+
       var customIcon = this.customIconElement;
       customIcon.parentNode.replaceChild(new UserPodCustomIcon(), customIcon);
     },
 
     /**
      * Initializes the pod after its properties set and added to a pod row.
      */
     initialize: function() {
       this.passwordElement.addEventListener('keydown',
           this.parentNode.handleKeyDown.bind(this.parentNode));
@@ skipping 13 matching lines @@
     /**
      * Resets tab order for pod elements to its initial state.
      */
     resetTabOrder: function() {
       // Note: the |mainInput| can be the pod itself.
       this.mainInput.tabIndex = -1;
       this.tabIndex = UserPodTabOrder.POD_INPUT;
     },
 
     /**
+     * Handles the user hitting 'submit' on the PIN keyboard.
+     * @param {Event} e Submit event object.
+     * @private
+     */
+    handlePinSubmitted_: function(e) {
+      var pin = e.detail.pin;
+      chrome.send('authenticateUserWithPin', [this.user.username, pin]);
+    },
+
+    /**
      * Handles keypress event (i.e. any textual input) on password input.
      * @param {Event} e Keypress Event object.
      * @private
      */
     handlePasswordKeyPress_: function(e) {
       // When tabbing from the system tray a tab key press is received. Suppress
       // this so as not to type a tab character into the password field.
       if (e.keyCode == 9) {
         e.preventDefault();
         return;
@@ skipping 2565 matching lines @@
        if (pod && pod.multiProfilesPolicyApplied) {
          pod.userTypeBubbleElement.classList.remove('bubble-shown');
        }
      }
   };
 
   return {
     PodRow: PodRow
   };
 });