This CL fixes the issue with login using alternative e-mails.

components/user_manager/user_manager.h

 // 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.
 
 #ifndef COMPONENTS_USER_MANAGER_USER_MANAGER_H_
 #define COMPONENTS_USER_MANAGER_USER_MANAGER_H_
 
 #include <string>
 
 #include "components/user_manager/user.h"
@@ skipping 341 matching lines @@
   // fills in |out_value|. Otherwise returns false.
   virtual bool GetKnownUserIntegerPref(const UserID& user_id,
                                        const std::string& path,
                                        int* out_value) = 0;
 
   // Updates user's identified by |user_id| integer preference |path|.
   virtual void SetKnownUserIntegerPref(const UserID& user_id,
                                        const std::string& path,
                                        const int in_value) = 0;
 
+  // Returns true if user's canonical email was found.
+  // Returns it in |out_email|.
+  virtual bool GetKnownUserCanonicalEmail(const UserID& user_id,
+                                          std::string* out_email) = 0;
+
   // Updates |gaia_id| for user with |user_id|.
   // TODO(antrim): Update this once UserID contains GAIA ID.
   virtual void UpdateGaiaID(const UserID& user_id,
                             const std::string& gaia_id) = 0;
 
   // Find GAIA ID for user with |user_id|, fill in |out_value| and return true
   // if GAIA ID was found or false otherwise.
   // TODO(antrim): Update this once UserID contains GAIA ID.
   virtual bool FindGaiaID(const UserID& user_id, std::string* out_value) = 0;
 
@@ skipping 44 matching lines @@
   static UserManager* GetForTesting();
 
   // Sets UserManager instance to the given |user_manager|.
   // Returns the previous value of the instance.
   static UserManager* SetForTesting(UserManager* user_manager);
 };
 
 }  // namespace user_manager
 
 #endif  // COMPONENTS_USER_MANAGER_USER_MANAGER_H_