Notify about major session changes events.

chrome/browser/ui/ash/session_state_delegate_chromeos.cc

 // 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.
 
 #include "chrome/browser/ui/ash/session_state_delegate_chromeos.h"
 
 #include "ash/multi_profile_uma.h"
 #include "ash/session_state_observer.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/chromeos/login/screen_locker.h"
 #include "chrome/browser/chromeos/login/user.h"
 #include "chrome/browser/chromeos/login/user_adding_screen.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "google_apis/gaia/gaia_auth_util.h"
 
-SessionStateDelegateChromeos::SessionStateDelegateChromeos() {
+SessionStateDelegateChromeos::SessionStateDelegateChromeos()
+    : state_(STATE_UNKNOWN) {
   chromeos::UserManager::Get()->AddSessionStateObserver(this);
+  chromeos::UserAddingScreen::Get()->AddObserver(this);
 }
 
 SessionStateDelegateChromeos::~SessionStateDelegateChromeos() {
+  chromeos::UserManager::Get()->RemoveSessionStateObserver(this);
+  chromeos::UserAddingScreen::Get()->RemoveObserver(this);
 }
 
 content::BrowserContext* SessionStateDelegateChromeos::GetBrowserContextByIndex(
     ash::MultiProfileIndex index) {
   DCHECK_LT(index, NumberOfLoggedInUsers());
   chromeos::User* user =
       chromeos::UserManager::Get()->GetLRULoggedInUsers()[index];
   DCHECK(user);
   return chromeos::UserManager::Get()->GetProfileByUser(user);
 }
@@ skipping 163 matching lines @@
   session_state_observer_list_.AddObserver(observer);
 }
 
 void SessionStateDelegateChromeos::RemoveSessionStateObserver(
     ash::SessionStateObserver* observer) {
   session_state_observer_list_.RemoveObserver(observer);
 }
 
 void SessionStateDelegateChromeos::ActiveUserChanged(
     const chromeos::User* active_user) {
+  SetSessionState(STATE_SESSION);
   FOR_EACH_OBSERVER(ash::SessionStateObserver,
                     session_state_observer_list_,
                     ActiveUserChanged(active_user->email()));
 }
 
 void SessionStateDelegateChromeos::UserAddedToSession(
     const chromeos::User* added_user) {
+  SetSessionState(STATE_SESSION);
   FOR_EACH_OBSERVER(ash::SessionStateObserver,
                     session_state_observer_list_,
                     UserAddedToSession(added_user->email()));
 }
+
+void SessionStateDelegateChromeos::OnUserAddingStarted() {
+  SetSessionState(STATE_LOGIN_SECONDARY);
+}
+
+void SessionStateDelegateChromeos::OnUserAddingFinished() {

[Mr4D (OOO till 08-26), 2014/04/10 01:33:08]

Do we also get here if the user cancels out of the "add user to session" screen?

[Nikita (slow), 2014/04/10 09:52:21]

Yes.

+  SetSessionState(STATE_SESSION);
+}
+
+void SessionStateDelegateChromeos::SetSessionState(SessionState new_state) {
+  if (state_ == new_state)
+    return;
+
+  state_ = new_state;
+  NotifySessionStateChanged();
+}
+
+void SessionStateDelegateChromeos::NotifySessionStateChanged() {
+  FOR_EACH_OBSERVER(ash::SessionStateObserver,
+                    session_state_observer_list_,
+                    SessionStateChanged(state_));
+}