UMA to track the reason for re-auth (draft).

ui/login/account_picker/screen_account_picker.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 Account picker screen implementation.
  */
 
 login.createScreen('AccountPickerScreen', 'account-picker', function() {
   /**
@@ skipping 149 matching lines @@
       var activatedPod = $('pod-row').activatedPod;
       if (!activatedPod) {
         $('bubble').showContentForElement($('pod-row'),
                                           cr.ui.Bubble.Attachment.RIGHT,
                                           error);
         return;
       }
       // Show web authentication if this is not a supervised user.
       if (loginAttempts > MAX_LOGIN_ATTEMPTS_IN_POD &&
           !activatedPod.user.supervisedUser) {
+        chrome.send('maxIncorrectPasswordAttempts',
+            [activatedPod.user.emailAddress]);
         activatedPod.showSigninUI();
       } else {
+        if (loginAttempts == 1) {
+          chrome.send('firstIncorrectPasswordAttempt',
+              [activatedPod.user.emailAddress]);
+        }
         // We want bubble's arrow to point to the first letter of input.
         /** @const */ var BUBBLE_OFFSET = 7;
         /** @const */ var BUBBLE_PADDING = 4;
         $('bubble').showContentForElement(activatedPod.mainInput,
                                           cr.ui.Bubble.Attachment.BOTTOM,
                                           error,
                                           BUBBLE_OFFSET, BUBBLE_PADDING);
         // Move error bubble up if it overlaps the shelf.
         var maxHeight =
             cr.ui.LoginUITools.getMaxHeightBeforeShelfOverlapping($('bubble'));
@@ skipping 177 matching lines @@
      * @param {string} userID The user ID of the public session
      * @param {string} locale The locale to which this list of keyboard layouts
      *     applies
      * @param {!Object} list List of available keyboard layouts
      */
     setPublicSessionKeyboardLayouts: function(userID, locale, list) {
       $('pod-row').setPublicSessionKeyboardLayouts(userID, locale, list);
     }
   };
 });