[Athena] Extract Chrome OS authentication stack

chrome/browser/chromeos/login/helper.h

 // Copyright (c) 2012 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.
 //
 // This file contains helper functions used by Chromium OS login.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_HELPER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_HELPER_H_
 
 #include <string>
@@ skipping 21 matching lines @@
 int GetCurrentUserImageSize();
 
 // Define the constants in |login| namespace to avoid potential
 // conflict with other chromeos components.
 namespace login {
 
 // Maximum size of user image, in which it should be saved to be properly
 // displayed under all possible DPI values.
 const int kMaxUserImageSize = 512;
 
-// Canonicalizes a GAIA user ID, accounting for the legacy guest mode user ID
-// which does trips up gaia::CanonicalizeEmail() because it does not contain an
-// @ symbol.
-std::string CanonicalizeUserID(const std::string& user_id);
-
 // Returns true if lock/login should scroll user pods into view itself when
 // virtual keyboard is shown and disable vk overscroll.
 bool LoginScrollIntoViewEnabled();
 
 // A helper class for easily mocking out Network*Handler calls for tests.
 class NetworkStateHelper {
  public:
   NetworkStateHelper();
   virtual ~NetworkStateHelper();
 
@@ skipping 12 matching lines @@
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NetworkStateHelper);
 };
 
 }  // namespace login
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_HELPER_H_