UMA for pin unlock success/failure.

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 1307 matching lines @@
       } else if (this.isAuthTypeUserClick) {
         Oobe.disableSigninUI();
         this.classList.toggle('signing-in', true);
         chrome.send('attemptUnlock', [this.user.username]);
       } else if (this.isAuthTypePassword) {
         var pinValue = this.pinKeyboard ? this.pinKeyboard.value : '';
         var password = this.passwordElement.value || pinValue;
         if (!password)
           return false;
         Oobe.disableSigninUI();
-        chrome.send('authenticateUser', [this.user.username, password]);
+        chrome.send('authenticateUser', [this.user.username, password,
+                                         this.isPinShown()]);
       } else {
         console.error('Activating user pod with invalid authentication type: ' +
             this.authType);
       }
 
       return true;
     },
 
     showSupervisedUserSigninWarning: function() {
       // Legacy supervised user token has been invalidated.
@@ skipping 2185 matching lines @@
        if (pod && pod.multiProfilesPolicyApplied) {
          pod.userTypeBubbleElement.classList.remove('bubble-shown');
        }
      }
   };
 
   return {
     PodRow: PodRow
   };
 });