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

components/user_manager/user_manager_base.h

Index: components/user_manager/user_manager_base.h
diff --git a/components/user_manager/user_manager_base.h b/components/user_manager/user_manager_base.h
index a89dcc1c81420dc0cb38b7787fa4b178bee5f9ba..a5f5f8fe4f24d7fc0f0ffdf5272c31656f7a033a 100644
--- a/components/user_manager/user_manager_base.h
+++ b/components/user_manager/user_manager_base.h
@@ -129,6 +129,8 @@ class USER_MANAGER_EXPORT UserManagerBase : public UserManager {
   void SetKnownUserIntegerPref(const UserID& user_id,
                                const std::string& path,
                                const int in_value) override;
+  bool GetKnownUserCanonicalEmail(const UserID& user_id,
+                                  std::string* out_email) override;
   void UpdateGaiaID(const UserID& user_id, const std::string& gaia_id) override;
   bool FindGaiaID(const UserID& user_id, std::string* out_value) override;
   void UpdateUsingSAML(const std::string& user_id,