session_manager: Tracks user sessions

components/session_manager/core/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 COMPONENTS_SESSION_MANAGER_CORE_SESSION_MANAGER_H_
 #define COMPONENTS_SESSION_MANAGER_CORE_SESSION_MANAGER_H_
 
+#include <vector>
+
 #include "base/macros.h"
 #include "components/session_manager/session_manager_export.h"
 #include "components/session_manager/session_manager_types.h"
 
+class AccountId;
+
 namespace session_manager {
 
 class SESSION_EXPORT SessionManager {
  public:
   SessionManager();
   virtual ~SessionManager();
 
   // Returns current SessionManager instance and NULL if it hasn't been
   // initialized yet.
   static SessionManager* Get();
 
-  SessionState session_state() const { return session_state_; }
-  virtual void SetSessionState(SessionState state);
+  void SetSessionState(SessionState state);
+
+  // Creates a session for the given user. The first one is for regular case
+  // and the 2nd one is for crash-and-restart case.
+  void CreateSession(const AccountId& user_account_id,

[achuithb, 2016/10/31 22:41:36]

I feel like I'm being nitpicky, and am fine with this if you strongly prefer
this, but I guess I don't understand why this function is necessary. 

There's only a few callsites that need to be updated, right? And you're already
updating them in this CL. Why not just set the boolean to false at the
callsites?

I think we avoid overloads by using different names. So maybe the second one
could be called CreateSessionAfterRestart for instance, if we want to make a
distinction.

https://google.github.io/styleguide/cppguide.html#Function_Overloading

[xiyuan, 2016/11/01 16:24:31]

All sites except one are passing a false for the flag. So it feels redundant.

Changed to use a separate name for restart case per discussion.

+                     const std::string& user_id_hash);
+  void CreateSession(const AccountId& user_account_id,
+                     const std::string& user_id_hash,
+                     bool browser_restart);
 
   // Returns true if we're logged in and browser has been started i.e.
   // browser_creator.LaunchBrowser(...) was called after sign in
   // or restart after crash.
   virtual bool IsSessionStarted() const;
 
   // Called when browser session is started i.e. after
   // browser_creator.LaunchBrowser(...) was called after user sign in.
   // When user is at the image screen IsUserLoggedIn() will return true
   // but IsSessionStarted() will return false. During the kiosk splash screen,
   // we perform additional initialization after the user is logged in but
   // before the session has been started.
   virtual void SessionStarted();
 
+  SessionState session_state() const { return session_state_; }
+  const std::vector<Session>& sessions() const { return sessions_; }
+
  protected:
+  // Notifies UserManager about a user signs in when creating a user session.
+  virtual void NotifyUserLoggedIn(const AccountId& user_account_id,
+                                  const std::string& user_id_hash,
+                                  bool browser_restart);
+
   // Sets SessionManager instance.
   static void SetInstance(SessionManager* session_manager);
 
  private:
   // Pointer to the existing SessionManager instance (if any).
   // Set in ctor, reset in dtor. Not owned since specific implementation of
   // SessionManager should decide on its own appropriate owner of SessionManager
   // instance. For src/chrome implementation such place is
   // g_browser_process->platform_part().
   static SessionManager* instance;
 
   SessionState session_state_ = SessionState::UNKNOWN;
 
   // True if SessionStarted() has been called.
   bool session_started_ = false;
 
+  // Id of the primary session, i.e. the first user session.
+  static const SessionId kPrimarySessionId = 1;
+
+  // ID assigned to the next session.
+  SessionId next_id_ = kPrimarySessionId;
+
+  // Keeps track of user sessions.
+  std::vector<Session> sessions_;
+
   DISALLOW_COPY_AND_ASSIGN(SessionManager);
 };
 
 }  // namespace session_manager
 
 #endif  // COMPONENTS_SESSION_MANAGER_CORE_SESSION_MANAGER_H_