UMA for pin unlock success/failure.

chromeos/login/auth/extended_authenticator_impl.cc

 // 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.
 
 #include "chromeos/login/auth/extended_authenticator_impl.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 337 matching lines @@
   }
 
   if (return_code == cryptohome::MOUNT_ERROR_USER_DOES_NOT_EXIST)
     state = NO_MOUNT;
 
   if (consumer_)
     consumer_->OnAuthenticationFailure(state);
 
   if (old_consumer_) {
     AuthFailure failure(AuthFailure::UNLOCK_FAILED);
+    failure.SetIsPinAttempt(user_context.IsUsingPin());
     old_consumer_->OnAuthFailure(failure);
   }
 }
 
 }  // namespace chromeos