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

chrome/browser/chromeos/login/signin/auth_sync_observer.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 "chrome/browser/chromeos/login/signin/auth_sync_observer.h"
 
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/prefs/pref_service.h"
+#include "chrome/browser/chromeos/login/reauth_stats.h"
 #include "chrome/browser/chromeos/login/users/chrome_user_manager.h"
 #include "chrome/browser/chromeos/login/users/supervised_user_manager.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "components/user_manager/user_manager.h"
 #include "components/user_manager/user_type.h"
 #include "content/public/browser/user_metrics.h"
 #include "google_apis/gaia/gaia_auth_util.h"
 
@@ skipping 41 matching lines @@
     // TODO(nkostylev): Remove after crosbug.com/25978 is implemented.
     LOG(WARNING) << "Invalidate OAuth token because of a sync error: "
                  << sync_service->GetAuthError().ToString();
     std::string email = user->email();
     DCHECK(!email.empty());
     // TODO(nkostyelv): Change observer after active user has changed.
     user_manager::User::OAuthTokenStatus old_status =
         user->oauth_token_status();
     user_manager::UserManager::Get()->SaveUserOAuthStatus(
         email, user_manager::User::OAUTH2_TOKEN_STATUS_INVALID);
+    RecordReauthReason(email, ReauthReason::SYNC_FAILED);
     if (user->GetType() == user_manager::USER_TYPE_SUPERVISED &&
         old_status != user_manager::User::OAUTH2_TOKEN_STATUS_INVALID) {
        // Attempt to restore token from file.
       ChromeUserManager::Get()
           ->GetSupervisedUserManager()
           ->LoadSupervisedUserToken(
               profile_,
               base::Bind(&AuthSyncObserver::OnSupervisedTokenLoaded,
                          base::Unretained(this)));
        content::RecordAction(
@@ skipping 12 matching lines @@
     }
   }
 }
 
 void AuthSyncObserver::OnSupervisedTokenLoaded(const std::string& token) {
   ChromeUserManager::Get()->GetSupervisedUserManager()->ConfigureSyncWithToken(
       profile_, token);
 }
 
 }  // namespace chromeos