session_manager: Create ChromeSessionManager early

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"
 
 namespace base {
 class CommandLine;
 }
 
 class Profile;
 
 namespace chromeos {
 
 class ChromeSessionManager : public session_manager::SessionManager {
  public:
-  static std::unique_ptr<session_manager::SessionManager> CreateSessionManager(
-      const base::CommandLine& parsed_command_line,
-      Profile* profile,
-      bool is_running_test);
+  ChromeSessionManager();
+  ~ChromeSessionManager() override;
 
- private:
-  explicit ChromeSessionManager(
-      session_manager::SessionManagerDelegate* delegate);
-  ~ChromeSessionManager() override;
+  // Initialize session manager on browser starts up. Runs different code
+  // path based on command line flags and policy. Possible scenarios include:
+  //   - Launches pre-session UI such as  out-of-box or login;
+  //   - Launches the auto launched kiosk app;
+  //   - Resumes user sessions on crash-and-restart;
+  //   - Starts a stub login session for dev or test;
+  void Initialize(const base::CommandLine& parsed_command_line,
+                  Profile* profile,
+                  bool is_running_test);
 
   // session_manager::SessionManager:
   void SessionStarted() override;
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(ChromeSessionManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SESSION_CHROME_SESSION_MANAGER_H_