user_manager: Remove deps on session_manager

chrome/browser/chromeos/login/session/chrome_session_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_SESSION_CHROME_SESSION_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SESSION_CHROME_SESSION_MANAGER_H_
 
 #include "base/macros.h"
 #include "components/session_manager/core/session_manager.h"
 
@@ skipping 10 matching lines @@
   static std::unique_ptr<session_manager::SessionManager> CreateSessionManager(
       const base::CommandLine& parsed_command_line,
       Profile* profile,
       bool is_running_test);
 
  private:
   explicit ChromeSessionManager(
       session_manager::SessionManagerDelegate* delegate);
   ~ChromeSessionManager() override;
 
+  // session_manager::SessionManager:
+  void SessionStarted() override;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeSessionManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SESSION_CHROME_SESSION_MANAGER_H_