Replace chromeos::UserManager::Get() with chromeos::GetUserManager().

chrome/browser/chromeos/login/users/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 CHROME_BROWSER_CHROMEOS_LOGIN_USERS_USER_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USERS_USER_MANAGER_H_
 
 #include <string>
 
 #include "chrome/browser/chromeos/login/user_flow.h"
@@ skipping 363 matching lines @@
 // construction and tears it down again on destruction.
 class ScopedTestUserManager {
  public:
   ScopedTestUserManager();
   ~ScopedTestUserManager();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedTestUserManager);
 };
 
+// Returns the UserManager singleton instance or |NULL| if the singleton has
+// either not been created yet or is already destroyed. This method is not
+// thread-safe and must be called from the main UI thread.
+// Note: Since UserManager class will be moved to compoments/ all clients should
+// use this getter and *not use* GetUserManager().
+UserManager* GetUserManager();
+
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USERS_USER_MANAGER_H_