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

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

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
index 951600b56888b8050c6199394d3183492a61f641..31df3b670526c70c76ccc11eb32d5ab000c790ab 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h
@@ -349,7 +349,7 @@ class SigninScreenHandler
   void HandleSignOutUser();
   void HandleOpenProxySettings();
   void HandleLoginVisible(const std::string& source);
-  void HandleCancelPasswordChangedFlow();
+  void HandleCancelPasswordChangedFlow(const std::string& user_id);
   void HandleCancelUserAdding();
   void HandleMigrateUserData(const std::string& password);
   void HandleResyncUserData();
@@ -367,6 +367,8 @@ class SigninScreenHandler
   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|.