ash/session_state_observer.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ASH_SESSION_STATE_OBSERVER_H_
   6 #define ASH_SESSION_STATE_OBSERVER_H_
   7
   8 #include <string>
   9
  10 #include "ash/ash_export.h"
  11 #include "base/basictypes.h"
  12
  13 namespace ash {
  14
  15 class ASH_EXPORT SessionStateObserver {
  16  public:
  17   // Called when active user has changed.
  18   virtual void ActiveUserChanged(const std::string& user_id) {}
  19
  20   // Called when another user gets added to the existing session.
  21   virtual void UserAddedToSession(const std::string& user_id) {}
  22
  23  protected:
  24   virtual ~SessionStateObserver() {}
  25 };
  26
  27 // A class to attach / detach an object as a session state observer with a
  28 // scoped pointer.
  29 class ASH_EXPORT ScopedSessionStateObserver {
  30  public:
  31   explicit ScopedSessionStateObserver(ash::SessionStateObserver* observer);
  32   virtual ~ScopedSessionStateObserver();
  33
  34  private:
  35   ash::SessionStateObserver* observer_;
  36
  37   DISALLOW_COPY_AND_ASSIGN(ScopedSessionStateObserver);
  38 };
  39
  40 }  // namespace ash
  41
  42 #endif  // ASH_SESSION_STATE_OBSERVER_H_