Notify about major session changes events.

ash/session_state_delegate.h

 // Copyright (c) 2013 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 ASH_SESSION_STATE_DELEGATE_H_
 #define ASH_SESSION_STATE_DELEGATE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 27 matching lines @@
 // TODO(oshima): Replace MultiProfileIndex with BrowsreContext, bacause
 // GetUserXXX are useful for non multi profile scenario in ash_shell.
 class ASH_EXPORT SessionStateDelegate {
  public:
   // Defines the cycle direction for |CycleActiveUser|.
   enum CycleUser {
     CYCLE_TO_NEXT_USER = 0,  // Cycle to the next user.
     CYCLE_TO_PREVIOUS_USER,  // Cycle to the previous user.
   };
 
+  // Defines session state i.e. whether session is running or not and
+  // whether user session is blocked by things like lock screen and
+  // multi-profile login.
+  enum SessionState {
+    STATE_UNKNOWN = 0,
+
+    // When primary user login UI is shown i.e. after boot or sign out,
+    // no active user session exists yet.
+    STATE_LOGIN_PRIMARY,
+
+    // Inside user session, no blocking UI (login/lock) is shown.
+    STATE_SESSION,
+
+    // User session is active, currently is locked.
+    STATE_LOCK,
+
+    // When secondary user login UI is shown i.e. other users are
+    // already logged in and is currently adding another user to the session.
+    STATE_LOGIN_SECONDARY,
+  };
+
   virtual ~SessionStateDelegate() {};
 
   // Returns the browser context for the user given by |index|.
   virtual content::BrowserContext* GetBrowserContextByIndex(
       MultiProfileIndex index) = 0;
 
   // Returns the browser context associated with the window.
   virtual content::BrowserContext* GetBrowserContextForWindow(
       aura::Window* window) = 0;
 
@@ skipping 63 matching lines @@
   virtual void CycleActiveUser(CycleUser cycle_user) = 0;
 
   // Adds or removes sessions state observer.
   virtual void AddSessionStateObserver(SessionStateObserver* observer) = 0;
   virtual void RemoveSessionStateObserver(SessionStateObserver* observer) = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SESSION_STATE_DELEGATE_H_