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

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h

 // Copyright (c) 2013 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.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 331 matching lines @@
   void HandleToggleEnableDebuggingScreen();
   void HandleToggleKioskEnableScreen();
   void HandleToggleResetScreen();
   void HandleToggleKioskAutolaunchScreen();
   void HandleCreateAccount();
   void HandleAccountPickerReady();
   void HandleWallpaperReady();
   void HandleSignOutUser();
   void HandleOpenProxySettings();
   void HandleLoginVisible(const std::string& source);
-  void HandleCancelPasswordChangedFlow();
+  void HandleCancelPasswordChangedFlow(const std::string& email);

[Nikita (slow), 2015/04/29 09:21:46]

nit: email -> user_id here and elsewhere in CL

[Ivan Podogov, 2015/04/29 10:34:24]

Done.

   void HandleCancelUserAdding();
   void HandleMigrateUserData(const std::string& password);
   void HandleResyncUserData();
   void HandleLoginUIStateChanged(const std::string& source, bool active);
   void HandleUnlockOnLoginSuccess();
   void HandleLoginScreenUpdate();
   void HandleShowLoadingTimeoutError();
   void HandleUpdateOfflineLogin(bool offline_login_active);
   void HandleShowSupervisedUserCreationScreen();
   void HandleFocusPod(const std::string& user_id);
   void HandleHardlockPod(const std::string& user_id);
   void HandleLaunchKioskApp(const std::string& app_id, bool diagnostic_mode);
   void HandleGetPublicSessionKeyboardLayouts(const std::string& user_id,
                                              const std::string& locale);
   void HandleCancelConsumerManagementEnrollment();
   void HandleGetTouchViewState();
   void HandleLogRemoveUserWarningShown();
+  void HandleFirstIncorrectPasswordAttempt(const std::string& email);
+  void HandleMaxIncorrectPasswordAttempts(const std::string& email);
 
   // Sends the list of |keyboard_layouts| available for the |locale| that is
   // currently selected for the public session identified by |user_id|.
   void SendPublicSessionKeyboardLayouts(
       const std::string& user_id,
       const std::string& locale,
       scoped_ptr<base::ListValue> keyboard_layouts);
 
   // Returns true iff
   // (i)   log in is restricted to some user list,
@@ skipping 114 matching lines @@
   scoped_ptr<ErrorScreensHistogramHelper> histogram_helper_;
 
   base::WeakPtrFactory<SigninScreenHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_