Deprecate CreateUserSessions

* Replace them with SimulateUserLogin
* I couldn't replace one for start_session in AshTestHelper because
  SimulateUserLogin calls StabilizeUI, which shouldn't be called at
  this point. I'll work on it in a follow up CL.
* Remove unnecessary CreateUserSessions. This was actually causing
  incorrect state transition.
* Created default email constexpr value for eacy transition. I also
  found many SimulateUserLogin usage juset use some random email.
* DetachedableBaseNotificationController was initialised before
  SystemNotificationController even though it has dependency.
  Unit test was testing "locked -> login_primary" transition, but not
  "locked -> active", and it was passing incorrectly.

Bug: 383441831
Test: All tests should still pass.

Change-Id: Iccca14f65ed50a938842ace202f1f263d224c2bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6089266
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1396256}

ash/ambient/ambient_controller_unittest.cc

@@ -2043,7 +2043,7 @@ TEST_F(AmbientControllerForManagedScreensaverLoginScreenTest,
   ASSERT_TRUE(GetContainerView());
 
   // Simulate user session start (e.g. user login)
-  CreateUserSessions(/*session_count=*/1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // Confirm that ambient mode is not shown if disabled. (disabled by default)
   FastForwardByLockScreenInactivityTimeout();
@@ -2093,7 +2093,7 @@ TEST_F(AmbientControllerForManagedScreensaverLoginScreenTest,
   EXPECT_FALSE(ambient_controller()->ShouldShowAmbientUi());
 
   // Simulate login
-  CreateUserSessions(/*session_count=*/1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_FALSE(ambient_controller()->ShouldShowAmbientUi());
 
   SetAmbientModeManagedScreensaverEnabled(true);
@@ -2126,7 +2126,7 @@ TEST_F(AmbientControllerForManagedScreensaverLoginScreenTest,
   EXPECT_FALSE(ambient_controller()->ShouldShowAmbientUi());
 
   // Simulate login
-  CreateUserSessions(/*session_count=*/1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_FALSE(ambient_controller()->ShouldShowAmbientUi());
 
   SetAmbientModeManagedScreensaverEnabled(true);

ash/detachable_base/detachable_base_notification_controller_unittest.cc

@@ -77,7 +77,7 @@ class DetachableBaseNotificationControllerTest : public NoSessionAshTestBase {
 
 TEST_F(DetachableBaseNotificationControllerTest,
        ShowPairingNotificationIfSessionNotBlocked) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // The first detachable base used by the user - no notification expected.
   detachable_base_handler()->PairChallengeSucceeded({0x01, 0x01});
@@ -98,7 +98,7 @@ TEST_F(DetachableBaseNotificationControllerTest,
 
 TEST_F(DetachableBaseNotificationControllerTest,
        ShowNotificationOnNonAuthenticatedBases) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   detachable_base_handler()->PairChallengeFailed();
   EXPECT_TRUE(IsBaseChangedNotificationVisible());
@@ -106,7 +106,7 @@ TEST_F(DetachableBaseNotificationControllerTest,
 
 TEST_F(DetachableBaseNotificationControllerTest,
        UpdateNotificationOnUserSwitch) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // The first detachable base used by the user - no notification expected.
   detachable_base_handler()->PairChallengeSucceeded({0x01, 0x01});
@@ -127,7 +127,7 @@ TEST_F(DetachableBaseNotificationControllerTest,
 
 TEST_F(DetachableBaseNotificationControllerTest,
        NonAuthenticatedBaseNotificationOnUserSwitch) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   detachable_base_handler()->PairChallengeFailed();
   EXPECT_TRUE(IsBaseChangedNotificationVisible());
@@ -185,12 +185,12 @@ TEST_F(DetachableBaseNotificationControllerTest,
   detachable_base_handler()->PairChallengeFailed();
   EXPECT_FALSE(IsBaseChangedNotificationVisible());
 
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_TRUE(IsBaseChangedNotificationVisible());
 }
 
 TEST_F(DetachableBaseNotificationControllerTest, NoNotificationOnLockScreen) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   // The first detachable base used by the user - no notification expected.
   detachable_base_handler()->PairChallengeSucceeded({0x01, 0x01});
 
@@ -205,7 +205,7 @@ TEST_F(DetachableBaseNotificationControllerTest, NoNotificationOnLockScreen) {
 
 TEST_F(DetachableBaseNotificationControllerTest,
        NoNotificationAfterLockScreenIfSetAsUsed) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   // The first detachable base used by the user - no notification expected.
   detachable_base_handler()->PairChallengeSucceeded({0x01, 0x01});
   BlockUserSession(UserSessionBlockReason::BLOCKED_BY_LOCK_SCREEN);
@@ -225,16 +225,17 @@ TEST_F(DetachableBaseNotificationControllerTest,
 // about the base.
 TEST_F(DetachableBaseNotificationControllerTest,
        NonAuthenticatedBaseNotificationNotShownOnLock) {
-  BlockUserSession(UserSessionBlockReason::BLOCKED_BY_LOCK_SCREEN);
+  ASSERT_TRUE(IsInSessionState(session_manager::SessionState::LOGIN_PRIMARY));
   detachable_base_handler()->PairChallengeFailed();
   EXPECT_FALSE(IsBaseChangedNotificationVisible());
 
-  UnblockUserSession();
+  SimulateUserLogin(kDefaultUserEmail);
+
   EXPECT_TRUE(IsBaseChangedNotificationVisible());
 }
 
 TEST_F(DetachableBaseNotificationControllerTest, NotificationOnUpdateRequired) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   detachable_base_handler()->BaseFirmwareUpdateNeeded();
   EXPECT_TRUE(IsBaseRequiresUpdateNotificationVisible());
@@ -253,7 +254,7 @@ TEST_F(DetachableBaseNotificationControllerTest,
   EXPECT_FALSE(IsBaseRequiresUpdateNotificationVisible());
 
   // Login, expect the notification to be shown.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_TRUE(IsBaseRequiresUpdateNotificationVisible());
 
   // The notification should be removed when the base gets detached.

ash/focus/ash_focus_rules_unittest.cc

@@ -38,7 +38,10 @@ class LockScreenSessionControllerClient : public TestSessionControllerClient {
                                     TestPrefServiceProvider* prefs_provider)
       : TestSessionControllerClient(controller, prefs_provider) {
     InitializeAndSetClient();
-    CreatePredefinedUserSessions(1);
+
+    Reset();
+    AddUserSession("user0@tray");
+    SetSessionState(session_manager::SessionState::ACTIVE);
   }
 
   LockScreenSessionControllerClient(const LockScreenSessionControllerClient&) =

ash/metrics/login_unlock_throughput_recorder_unittest.cc

@@ -201,7 +201,7 @@ class LoginUnlockThroughputRecorderTestBase : public LoginTestBase {
   }
 
   void LoginOwner() {
-    CreateUserSessions(1);
+    SimulateUserLogin(kDefaultUserEmail);
     LoginState::Get()->SetLoggedInState(LoginState::LOGGED_IN_ACTIVE,
                                         LoginState::LOGGED_IN_USER_REGULAR);
   }

ash/metrics/unlock_throughput_recorder_unittest.cc

@@ -40,7 +40,7 @@ class UnlockThroughputRecorderTest : public LoginTestBase,
 
  protected:
   void LoginOwner() {
-    CreateUserSessions(1);
+    SimulateUserLogin(kDefaultUserEmail);
     LoginState::Get()->SetLoggedInState(LoginState::LOGGED_IN_ACTIVE,
                                         LoginState::LOGGED_IN_USER_REGULAR);
   }

ash/metrics/user_metrics_recorder_unittest.cc

@@ -63,7 +63,7 @@ TEST_F(UserMetricsRecorderTest, VerifyIsUserInActiveDesktopEnvironmentValues) {
   EXPECT_FALSE(test_api().IsUserInActiveDesktopEnvironment());
 
   // Environment is active after login.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ASSERT_TRUE(session->IsActiveUserSessionStarted());
   EXPECT_TRUE(test_api().IsUserInActiveDesktopEnvironment());
 
@@ -97,7 +97,7 @@ TEST_F(UserMetricsRecorderTest,
 // recorded when a user is active in a desktop environment.
 TEST_F(UserMetricsRecorderTest,
        VerifyStatsRecordedWhenUserInActiveDesktopEnvironment) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ASSERT_TRUE(test_api().IsUserInActiveDesktopEnvironment());
   test_api().RecordPeriodicMetrics();
 
@@ -109,7 +109,7 @@ TEST_F(UserMetricsRecorderTest,
 // Verify the shelf item counts recorded by the
 // UserMetricsRecorder::RecordPeriodicMetrics() method.
 TEST_F(UserMetricsRecorderTest, ValuesRecordedByRecordShelfItemCounts) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // Make sure the shelf model is empty at first.
   ShelfModel* shelf_model = ShelfModel::Get();

ash/root_window_controller_unittest.cc

@@ -444,7 +444,7 @@ TEST_F(RootWindowControllerTest, ModalContainerNotLoggedInLoggedIn) {
   login_modal_widget->Close();
 
   // Configure user session environment.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_EQ(1, session_controller->NumberOfLoggedInUsers());
   EXPECT_TRUE(session_controller->IsActiveUserSessionStarted());
   EXPECT_EQ(GetLayoutManager(controller, kShellWindowId_SystemModalContainer),

ash/session/test_session_controller_client.cc

@@ -117,25 +117,6 @@ void TestSessionControllerClient::SetIsDemoSession() {
   controller_->SetSessionInfo(session_info_);
 }
 
-void TestSessionControllerClient::CreatePredefinedUserSessions(int count) {
-  DCHECK_GT(count, 0);
-
-  // Resets the controller's state.
-  Reset();
-
-  // Adds user sessions with numbered emails if more are needed.
-  for (int numbered_user_index = 0; numbered_user_index < count;
-       ++numbered_user_index) {
-    AddUserSession(base::StringPrintf("user%d@tray", numbered_user_index));
-  }
-
-  // Sets the first user as active.
-  SwitchActiveUser(controller_->GetUserSession(0)->user_info.account_id);
-
-  // Updates session state after adding user sessions.
-  SetSessionState(session_manager::SessionState::ACTIVE);
-}
-
 void TestSessionControllerClient::AddUserSession(
     const std::string& display_email,
     user_manager::UserType user_type,
@@ -349,6 +330,12 @@ std::optional<int> TestSessionControllerClient::GetExistingUsersCount() const {
   return existing_users_count_;
 }
 
+int TestSessionControllerClient::NumberOfLoggedInUsers() const {
+  // This should be migrated to GetExistingUserCount when
+  // TestSessionControllerImpl is removed.
+  return controller_->NumberOfLoggedInUsers();
+}
+
 void TestSessionControllerClient::DoSwitchUser(const AccountId& account_id,
                                                bool switch_user) {
   if (!switch_user)

ash/session/test_session_controller_client.h

@@ -80,12 +80,6 @@ class TestSessionControllerClient : public SessionControllerClient {
   void SetIsRunningInAppMode(bool app_mode);
   void SetIsDemoSession();
 
-  // Creates the |count| pre-defined user sessions. The users are named by
-  // numbers using "user%d@tray" template. The first user is set as active user
-  // to be consistent with crash-and-restore scenario.  Note that existing user
-  // sessions prior this call will be removed without sending out notifications.
-  void CreatePredefinedUserSessions(int count);
-
   // Adds a user session from a given display email. If |provide_pref_service|
   // is true, eagerly inject a PrefService for this user. |is_new_profile|
   // indicates whether the user has a newly created profile on the device.
@@ -174,6 +168,8 @@ class TestSessionControllerClient : public SessionControllerClient {
     default_provide_pref_service_ = default_provide_pref_service;
   }
 
+  int NumberOfLoggedInUsers() const;
+
  private:
   void DoSwitchUser(const AccountId& account_id, bool switch_user);
 

ash/shelf/home_button_unittest.cc

@@ -1002,7 +1002,9 @@ TEST_F(HomeButtonAnimationTest, NonAnimatedLayoutDuringAnimation) {
 
 TEST_P(HomeButtonTest, LongPressGesture) {
   // Simulate two users with primary user as active.
-  CreateUserSessions(2);
+  auto primary = SimulateUserLogin(kDefaultUserEmail);
+  SimulateUserLogin(kDefaultUserEmail);
+  SwitchActiveUser(primary);
 
   // Enable the Assistant in system settings.
   prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
@@ -1033,7 +1035,9 @@ TEST_P(HomeButtonTest, LongPressGesture) {
 
 TEST_P(HomeButtonTest, LongPressGestureInTabletMode) {
   // Simulate two users with primary user as active.
-  CreateUserSessions(2);
+  auto primary = SimulateUserLogin(kDefaultUserEmail);
+  SimulateUserLogin(kDefaultUserEmail);
+  SwitchActiveUser(primary);
 
   // Enable the Assistant in system settings.
   prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
@@ -1109,7 +1113,9 @@ TEST_P(HomeButtonTest, LongPressGestureWithSecondaryUser) {
 
 TEST_P(HomeButtonTest, LongPressGestureWithSettingsDisabled) {
   // Simulate two user with primary user as active.
-  CreateUserSessions(2);
+  auto primary = SimulateUserLogin(kDefaultUserEmail);
+  SimulateUserLogin(kDefaultUserEmail);
+  SwitchActiveUser(primary);
 
   // Simulate a user who has already completed setup flow, but disabled the
   // Assistant in settings.

ash/shelf/home_to_overview_nudge_controller_unittest.cc

@@ -48,7 +48,8 @@ class WidgetCloseObserver {
   base::WeakPtr<views::Widget> widget_;
 };
 
-class HomeToOverviewNudgeControllerWithNudgesDisabledTest : public AshTestBase {
+class HomeToOverviewNudgeControllerWithNudgesDisabledTest
+    : public NoSessionAshTestBase {
  public:
   HomeToOverviewNudgeControllerWithNudgesDisabledTest() {
     scoped_feature_list_.InitAndDisableFeature(
@@ -67,7 +68,7 @@ class HomeToOverviewNudgeControllerWithNudgesDisabledTest : public AshTestBase {
   base::test::ScopedFeatureList scoped_feature_list_;
 };
 
-class HomeToOverviewNudgeControllerTest : public AshTestBase {
+class HomeToOverviewNudgeControllerTest : public NoSessionAshTestBase {
  public:
   HomeToOverviewNudgeControllerTest() {
     scoped_feature_list_.InitAndEnableFeature(
@@ -82,7 +83,7 @@ class HomeToOverviewNudgeControllerTest : public AshTestBase {
 
   // AshTestBase:
   void SetUp() override {
-    AshTestBase::SetUp();
+    NoSessionAshTestBase::SetUp();
     GetSessionControllerClient()->SetSessionState(
         session_manager::SessionState::LOGIN_PRIMARY);
     test_clock_.Advance(base::Hours(2));
@@ -90,7 +91,7 @@ class HomeToOverviewNudgeControllerTest : public AshTestBase {
   }
   void TearDown() override {
     contextual_tooltip::ClearClockOverrideForTesting();
-    AshTestBase::TearDown();
+    NoSessionAshTestBase::TearDown();
   }
 
   HomeToOverviewNudgeController* GetNudgeController() {
@@ -186,7 +187,7 @@ TEST_F(HomeToOverviewNudgeControllerWithNudgesDisabledTest,
                    ->shelf_layout_manager()
                    ->home_to_overview_nudge_controller_for_testing());
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   std::unique_ptr<aura::Window> window_1 =
       CreateTestWindow(gfx::Rect(0, 0, 400, 400));
@@ -205,7 +206,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, NoNudgeBeforeLogin) {
   TabletModeControllerTestApi().EnterTabletMode();
   EXPECT_FALSE(GetNudgeController());
 
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_TRUE(GetNudgeController());
 }
 
@@ -214,7 +215,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, NoNudgeBeforeLogin) {
 // subsequent shows, the nudge should be hidden after a timeout.
 TEST_F(HomeToOverviewNudgeControllerTest, ShownOnHomeScreen) {
   base::HistogramTester histogram_tester;
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // The nudge should not be shown in clamshell.
   EXPECT_FALSE(GetNudgeController());
@@ -286,7 +287,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, ShownOnHomeScreen) {
 // Tests that the nudge eventually stops showing.
 TEST_F(HomeToOverviewNudgeControllerTest, ShownLimitedNumberOfTimes) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
   ASSERT_TRUE(GetNudgeController());
 
@@ -317,7 +318,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, ShownLimitedNumberOfTimes) {
 TEST_F(HomeToOverviewNudgeControllerTest, HiddenOnTabletModeExit) {
   base::HistogramTester histogram_tester;
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -335,7 +336,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, HiddenOnTabletModeExit) {
 // Tests that the nudge show is canceled when tablet mode exits.
 TEST_F(HomeToOverviewNudgeControllerTest, ShowCanceledOnTabletModeExit) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -354,7 +355,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, ShowCanceledOnTabletModeExit) {
 TEST_F(HomeToOverviewNudgeControllerTest,
        ShowAnimationCanceledOnTabletModeExit) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -378,7 +379,7 @@ TEST_F(HomeToOverviewNudgeControllerTest,
 // Tests that the nudge is hidden when the screen is locked.
 TEST_F(HomeToOverviewNudgeControllerTest, HiddenOnScreenLock) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -404,7 +405,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, HiddenOnScreenLock) {
 // show timer runs.
 TEST_F(HomeToOverviewNudgeControllerTest, InAppShelfShownBeforeShowTimer) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -433,7 +434,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, InAppShelfShownBeforeShowTimer) {
 // animation to show the nudge.
 TEST_F(HomeToOverviewNudgeControllerTest, NudgeHiddenDuringShowAnimation) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -484,7 +485,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, NudgeHiddenDuringShowAnimation) {
 // Tests that there is no crash if the nudge widget gets closed unexpectedly.
 TEST_F(HomeToOverviewNudgeControllerTest, NoCrashIfNudgeWidgetGetsClosed) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -504,7 +505,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, NoCrashIfNudgeWidgetGetsClosed) {
 TEST_F(HomeToOverviewNudgeControllerTest, TapOnTheNudgeClosesTheNudge) {
   base::HistogramTester histogram_tester;
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -529,7 +530,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, TapOnTheNudgeClosesTheNudge) {
 
 TEST_F(HomeToOverviewNudgeControllerTest, TapOnTheNudgeDuringShowAnimation) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList extra_windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -583,7 +584,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, TapOnTheNudgeDuringShowAnimation) {
 // times.
 TEST_F(HomeToOverviewNudgeControllerTest, NoNudgeAfterSuccessfulGestures) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList windows = CreateAndMinimizeWindows(2);
 
   EXPECT_FALSE(GetNudgeController()->nudge_for_testing());
@@ -648,7 +649,7 @@ TEST_F(HomeToOverviewNudgeControllerTest, NoNudgeAfterSuccessfulGestures) {
 // widget works - i.e. that home still transitions to overview.
 TEST_F(HomeToOverviewNudgeControllerTest, HomeToOverviewGestureFromNudge) {
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList windows = CreateAndMinimizeWindows(2);
 
   EXPECT_FALSE(GetNudgeController()->nudge_for_testing());
@@ -691,7 +692,7 @@ TEST_F(HomeToOverviewNudgeControllerTest,
        NudgeBoundsUpdatedOnDisplayBoundsChange) {
   UpdateDisplay("768x1200");
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList windows = CreateAndMinimizeWindows(2);
 
   ASSERT_TRUE(GetNudgeController());
@@ -719,7 +720,7 @@ TEST_P(HomeToOverviewNudgeControllerTestWithA11yPrefs,
   // Enters tablet mode and sets up two minimized windows. This will create the
   // show nudge timer.
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   ScopedWindowList windows = CreateAndMinimizeWindows(2);
   ASSERT_TRUE(GetNudgeController());
   EXPECT_TRUE(GetNudgeController()->HasShowTimerForTesting());
@@ -741,15 +742,13 @@ TEST_P(HomeToOverviewNudgeControllerTestWithA11yPrefs,
        DisableNudgesForShelfControls) {
   SCOPED_TRACE(testing::Message() << "Pref=" << GetParam());
   // Enabling accessibility shelf controls should disable the nudge.
-  Shell::Get()
-      ->session_controller()
-      ->GetLastActiveUserPrefService()
-      ->SetBoolean(GetParam(), true);
+  Shell::Get()->session_controller()->GetActivePrefService()->SetBoolean(
+      GetParam(), true);
 
   // Enters tablet mode and sets up two minimized windows. This should not
   // trigger the nudge show timer because shelf controls are on.
   TabletModeControllerTestApi().EnterTabletMode();
-  CreateUserSessions(1);
+  SimulateNewUserFirstLogin("test@gmail.com");
   ScopedWindowList windows = CreateAndMinimizeWindows(2);
 
   EXPECT_FALSE(GetNudgeController());

ash/shelf/login_shelf_view_unittest.cc

@@ -228,7 +228,7 @@ TEST_F(LoginShelfViewTest,
        ShouldUpdateUiAfterShutdownPolicyChangeAtLockScreen) {
   EXPECT_TRUE(ShowsShelfButtons({}));
 
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -252,7 +252,7 @@ TEST_F(LoginShelfViewTest, ShouldUpdateUiBasedOnShutdownPolicyInActiveSession) {
   // The initial state of |reboot_on_shutdown| is false.
   EXPECT_TRUE(ShowsShelfButtons({}));
 
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifyShutdownPolicyChanged(true /*reboot_on_shutdown*/);
 
   NotifySessionStateChanged(SessionState::LOCKED);
@@ -270,7 +270,7 @@ TEST_F(LoginShelfViewTest, ShouldNotShowAppsButtonAfterSessionStarted) {
   EXPECT_TRUE(
       login_shelf_view_->GetViewByID(LoginShelfView::kApps)->GetVisible());
 
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_FALSE(
       login_shelf_view_->GetViewByID(LoginShelfView::kApps)->GetVisible());
 }
@@ -470,7 +470,7 @@ TEST_F(LoginShelfViewTest, ClickShutdownButton) {
 }
 
 TEST_F(LoginShelfViewTest, ClickShutdownButtonOnLockScreen) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   ShutdownAndConfirm();
   EXPECT_TRUE(Shell::Get()->lock_state_controller()->ShutdownRequested());
@@ -480,13 +480,13 @@ TEST_F(LoginShelfViewTest, ClickShutdownButtonOnLockScreen) {
 // session that starts with side shelf. See https://crbug.com/1050192.
 TEST_F(LoginShelfViewTest,
        ClickShutdownButtonOnLockScreenWithVerticalInSessionShelf) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetShelfAlignmentPref(
       Shell::Get()->session_controller()->GetPrimaryUserPrefService(),
       GetPrimaryDisplay().id(), ShelfAlignment::kLeft);
   ClearLogin();
 
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
 
   ShutdownAndConfirm();
@@ -495,7 +495,7 @@ TEST_F(LoginShelfViewTest,
 
 TEST_F(LoginShelfViewTest, ClickRestartButton) {
   // The Restart button is not available in OOBE session state.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
 
   NotifyShutdownPolicyChanged(true /*reboot_on_shutdown*/);
@@ -507,7 +507,7 @@ TEST_F(LoginShelfViewTest, ClickRestartButton) {
 }
 
 TEST_F(LoginShelfViewTest, ClickSignOutButton) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_EQ(session_manager::SessionState::ACTIVE,
             Shell::Get()->session_controller()->GetSessionState());
 
@@ -520,7 +520,7 @@ TEST_F(LoginShelfViewTest, ClickSignOutButton) {
 TEST_F(LoginShelfViewTest, ClickCancelButton) {
   auto client = std::make_unique<MockLoginScreenClient>();
   EXPECT_CALL(*client, CancelAddUser());
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOGIN_SECONDARY);
   Click(LoginShelfView::kCancel);
 }
@@ -544,7 +544,7 @@ TEST_F(LoginShelfViewTest, ClickEnterpriseEnrollmentButton) {
 }
 
 TEST_F(LoginShelfViewTest, TabGoesFromShelfToStatusAreaAndBackToShelf) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -584,7 +584,7 @@ TEST_F(LoginShelfViewTest, TabGoesFromShelfToStatusAreaAndBackToShelf) {
 }
 
 TEST_F(LoginShelfViewTest, LoginShelfButtonTooltipText) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -638,7 +638,7 @@ TEST_F(LoginShelfViewTest, LoginShelfButtonTooltipText) {
 }
 
 TEST_F(LoginShelfViewTest, LoginShelfButtonTooltipTextAccessibility) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -837,7 +837,7 @@ TEST_F(LoginShelfViewTest, ParentAccessButtonVisibility) {
 }
 
 TEST_F(LoginShelfViewTest, ParentAccessButtonVisibilityChangeOnLockScreen) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -949,7 +949,7 @@ TEST_F(LoginShelfViewTest, MouseWheelOnLoginShelf) {
     test_mouse_wheel_noop(location);
   }
 
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
 
   for (const auto& location : kLocations) {
@@ -1045,7 +1045,7 @@ TEST_F(LoginShelfViewTest, AccessiblePreviousAndNextFocus) {
 
   // Simulate the lock screen scenario to verify the previous focus is updated.
   Shell::Get()->login_screen_controller()->ShowLockScreen();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
 
   data = ui::AXNodeData();
@@ -1199,7 +1199,7 @@ class LoginShelfViewWithShutdownConfirmationTest : public LoginShelfViewTest {
 // shutdown button on the lockscreen
 TEST_F(LoginShelfViewWithShutdownConfirmationTest,
        ShouldShowAfterShutdownButtonLockSession) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -1242,7 +1242,7 @@ TEST_F(LoginShelfViewWithShutdownConfirmationTest,
 // cancel button on the shutdown confirmation bubble and could be shown again.
 TEST_F(LoginShelfViewWithShutdownConfirmationTest,
        ShouldCloseAfterCancelButton) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -1283,7 +1283,7 @@ TEST_F(LoginShelfViewWithShutdownConfirmationTest,
 // down.
 TEST_F(LoginShelfViewWithShutdownConfirmationTest,
        ShouldCloseAndShutdownAfterConfirmButton) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -1311,7 +1311,7 @@ TEST_F(LoginShelfViewWithShutdownConfirmationTest,
 
 // Checks that shutdown confirmation bubble disappears after inactive.
 TEST_F(LoginShelfViewWithShutdownConfirmationTest, ShouldCloseAfterInactive) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -1341,7 +1341,7 @@ TEST_F(LoginShelfViewWithShutdownConfirmationTest, ShouldCloseAfterInactive) {
 // Checks that shutdown confirmation was first cancelled, then confirmed
 TEST_F(LoginShelfViewWithShutdownConfirmationTest,
        ShouldCloseAndShutdownAfterCancelAndConfirmButton) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -1444,7 +1444,7 @@ TEST_F(LoginShelfViewWithShutdownConfirmationTest, DisplayOff) {
 }
 
 TEST_F(LoginShelfViewWithShutdownConfirmationTest, ClickRestartButton) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   EXPECT_TRUE(
       ShowsShelfButtons({LoginShelfView::kShutdown, LoginShelfView::kSignOut}));
@@ -1460,7 +1460,7 @@ TEST_F(LoginShelfViewWithShutdownConfirmationTest, ClickRestartButton) {
 
 TEST_F(LoginShelfViewWithShutdownConfirmationTest,
        ShelfShutdownConfirmationBubbleAccessibleProperties) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   NotifySessionStateChanged(SessionState::LOCKED);
   Click(LoginShelfView::kShutdown);
   auto* confirmation_bubble =

ash/shelf/shelf_widget_unittest.cc

@@ -401,7 +401,7 @@ TEST_F(ShelfWidgetTest, ShelfInitiallySizedAfterLogin) {
   ASSERT_TRUE(shelf_widget2);
 
   // Simulate login.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   const int total_width1 =
       screen_util::GetDisplayBoundsWithShelf(shelf_widget1->GetNativeWindow())
@@ -967,7 +967,7 @@ class ShelfWidgetAfterLoginTest : public AshTestBase {
                  ShelfVisibilityState expected_shelf_visibility_state,
                  ShelfAutoHideState expected_shelf_auto_hide_state) {
     // Simulate login.
-    CreateUserSessions(1);
+    SimulateUserLogin(kDefaultUserEmail);
 
     // Simulate shelf settings being applied from profile prefs.
     Shelf* shelf = GetPrimaryShelf();
@@ -1001,7 +1001,7 @@ TEST_F(ShelfWidgetAfterLoginTest, InitialValues) {
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->GetAutoHideState());
 
   // Simulate login.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // Ensure settings are correct after login.
   EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());

ash/shelf/shelf_window_watcher_unittest.cc

@@ -332,7 +332,7 @@ TEST_F(ShelfWindowWatcherSessionStartTest, PreExistingWindow) {
   EXPECT_EQ(0, model->item_count());
 
   // Start the test user session; ShelfWindowWatcher will find the open window.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_EQ(1, model->item_count());
 }
 

ash/shell.cc

@@ -994,6 +994,13 @@ Shell::~Shell() {
   // notification.
   focus_mode_controller_.reset();
 
+  // DetachableBaseNotificationController depends on DetachableBaseHandler, and
+  // has to be destructed before it.
+  detachable_base_notification_controller_.reset();
+  // DetachableBaseHandler depends on the PrefService and must be destructed
+  // before it.
+  detachable_base_handler_.reset();
+
   system_notification_controller_.reset();
   // Should be destroyed after Shelf and |system_notification_controller_|.
   system_tray_model_.reset();
@@ -1164,12 +1171,6 @@ Shell::~Shell() {
   // TouchDevicesController depends on the PrefService and must be destructed
   // before it.
   touch_devices_controller_ = nullptr;
-  // DetachableBaseNotificationController depends on DetachableBaseHandler, and
-  // has to be destructed before it.
-  detachable_base_notification_controller_.reset();
-  // DetachableBaseHandler depends on the PrefService and must be destructed
-  // before it.
-  detachable_base_handler_.reset();
 
   diagnostics_log_controller_.reset();
 
@@ -1276,11 +1277,6 @@ void Shell::Init(
   // These controllers call Shell::Get() in their constructors, so they cannot
   // be in the member initialization list.
   touch_devices_controller_ = std::make_unique<TouchDevicesController>();
-  detachable_base_handler_ =
-      std::make_unique<DetachableBaseHandler>(local_state_);
-  detachable_base_notification_controller_ =
-      std::make_unique<DetachableBaseNotificationController>(
-          detachable_base_handler_.get());
   display_speaker_controller_ = std::make_unique<DisplaySpeakerController>();
   policy_recommendation_restorer_ =
       std::make_unique<PolicyRecommendationRestorer>();
@@ -1725,6 +1721,13 @@ void Shell::Init(
   system_notification_controller_ =
       std::make_unique<SystemNotificationController>();
 
+  // They listen to session controller after notification controller.
+  detachable_base_handler_ =
+      std::make_unique<DetachableBaseHandler>(local_state_);
+  detachable_base_notification_controller_ =
+      std::make_unique<DetachableBaseNotificationController>(
+          detachable_base_handler_.get());
+
   // WmModeController should be created before initializing the window tree
   // hosts, since the latter will initialize the shelf on each display, which
   // hosts the WM mode tray button.

ash/shell.h

@@ -1063,9 +1063,6 @@ class ASH_EXPORT Shell : public SessionObserver,
   std::unique_ptr<DesksController> desks_controller_;
   std::unique_ptr<SavedDeskController> saved_desk_controller_;
   std::unique_ptr<SavedDeskDelegate> saved_desk_delegate_;
-  std::unique_ptr<DetachableBaseHandler> detachable_base_handler_;
-  std::unique_ptr<DetachableBaseNotificationController>
-      detachable_base_notification_controller_;
   std::unique_ptr<diagnostics::DiagnosticsLogController>
       diagnostics_log_controller_;
   std::unique_ptr<DisplayHighlightController> display_highlight_controller_;
@@ -1150,6 +1147,9 @@ class ASH_EXPORT Shell : public SessionObserver,
   std::unique_ptr<AcceleratorTracker> accelerator_tracker_;
   std::unique_ptr<ShutdownControllerImpl> shutdown_controller_;
   std::unique_ptr<SystemNotificationController> system_notification_controller_;
+  std::unique_ptr<DetachableBaseHandler> detachable_base_handler_;
+  std::unique_ptr<DetachableBaseNotificationController>
+      detachable_base_notification_controller_;
   std::unique_ptr<SystemNudgePauseManagerImpl> system_nudge_pause_manager_;
   std::unique_ptr<SystemTrayModel> system_tray_model_;
   std::unique_ptr<SystemTrayNotifier> system_tray_notifier_;

ash/system/accessibility/accessibility_feature_pod_controller_unittest.cc

@@ -95,7 +95,7 @@ TEST_F(AccessibilityFeaturePodControllerTest, ButtonVisibilityNotLoggedIn) {
 }
 
 TEST_F(AccessibilityFeaturePodControllerTest, ButtonVisibilityLoggedIn) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   GetPrimaryUnifiedSystemTray()->ShowBubble();
   auto* tile = views::AsViewClass<FeatureTile>(
       GetPrimaryUnifiedSystemTray()->bubble()->GetBubbleView()->GetViewByID(

ash/system/nearby_share/nearby_share_feature_pod_controller_unittest.cc

@@ -97,14 +97,14 @@ TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisibilityNotLoggedIn) {
 }
 
 TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisibilityLoggedIn) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpButton();
   // If logged in, it should be visible.
   EXPECT_TRUE(IsButtonVisible());
 }
 
 TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisibilityLocked) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   BlockUserSession(UserSessionBlockReason::BLOCKED_BY_LOCK_SCREEN);
 
   // Showing the lock screen closes the system tray bubble, so re-show it before
@@ -117,7 +117,7 @@ TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisibilityLocked) {
 }
 
 TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisibilityLoginScreen) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   BlockUserSession(UserSessionBlockReason::BLOCKED_BY_LOGIN_SCREEN);
   SetUpButton();
   // If the login screen is showing (e.g. multi-user signin), it should not be
@@ -126,7 +126,7 @@ TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisibilityLoginScreen) {
 }
 
 TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisiblilityHiddenByDelegate) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->set_is_pod_button_visible(false);
   SetUpButton();
   // If NearbyShareDelegate::IsPodButtonVisible() returns false, it should
@@ -136,7 +136,7 @@ TEST_F(NearbyShareFeaturePodControllerTest, ButtonVisiblilityHiddenByDelegate) {
 
 TEST_F(NearbyShareFeaturePodControllerTest,
        ButtonToggledByHighVisibilityEnabledEvent) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpButton();
   ASSERT_FALSE(IsButtonToggled());
   nearby_share_controller_->HighVisibilityEnabledChanged(true);
@@ -146,7 +146,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 }
 
 TEST_F(NearbyShareFeaturePodControllerTest, ButtonPressTogglesHighVisibility) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpButton();
   test_delegate_->method_calls().clear();
 
@@ -164,7 +164,7 @@ TEST_F(NearbyShareFeaturePodControllerTest, ButtonPressTogglesHighVisibility) {
 }
 
 TEST_F(NearbyShareFeaturePodControllerTest, IconUMATracking) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpButton();
 
   std::string histogram_prefix;
@@ -193,7 +193,7 @@ TEST_F(NearbyShareFeaturePodControllerTest, IconUMATracking) {
 }
 
 TEST_F(NearbyShareFeaturePodControllerTest, ButtonEnabledStateVisibility) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->set_is_enabled(false);
   SetUpButton();
   // If NearbyShareDelegate::IsEnabled() returns false, the button should
@@ -204,7 +204,7 @@ TEST_F(NearbyShareFeaturePodControllerTest, ButtonEnabledStateVisibility) {
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_ButtonToggledOnYourDevicesVisibility) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   // Default visibility is Your devices.
   SetUpButton();
   EXPECT_TRUE(IsButtonToggled());
@@ -213,7 +213,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_ButtonToggledOnContactsVisibility) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->set_visibility(
       ::nearby_share::mojom::Visibility::kAllContacts);
   SetUpButton();
@@ -223,7 +223,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_ButtonToggledOnSelectedContactsVisibility) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->set_visibility(
       ::nearby_share::mojom::Visibility::kSelectedContacts);
   SetUpButton();
@@ -233,7 +233,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_ButtonToggledOnHiddenVisibility) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->set_visibility(::nearby_share::mojom::Visibility::kNoOne);
   SetUpButton();
   EXPECT_TRUE(IsButtonToggled());
@@ -242,7 +242,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_ButtonToggledOn_HighVisibilityEnabled) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->set_is_high_visibility_on(true);
   SetUpButton();
   EXPECT_TRUE(IsButtonToggled());
@@ -251,7 +251,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_ButtonToggledOn_QuickShareEnabled) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->SetEnabled(true);
   SetUpButton();
   EXPECT_TRUE(IsButtonToggled());
@@ -260,7 +260,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_ButtonToggledOff_QuickShareDisabled) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->SetEnabled(false);
   SetUpButton();
   EXPECT_FALSE(IsButtonToggled());
@@ -269,7 +269,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_IconTogglesButtonOn_QuickShareOn_OnPress) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->SetEnabled(false);
   SetUpButton();
   EXPECT_FALSE(IsButtonToggled());
@@ -282,7 +282,7 @@ TEST_F(NearbyShareFeaturePodControllerTest,
 TEST_F(NearbyShareFeaturePodControllerTest,
        QuickShareV2_IconTogglesButtonOff_QuickShareOff_OnPress) {
   EnableQuickShareV2();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   test_delegate_->SetEnabled(true);
   SetUpButton();
   EXPECT_TRUE(IsButtonToggled());

ash/system/network/network_list_network_item_view_unittest.cc

@@ -243,7 +243,7 @@ TEST_F(NetworkListNetworkItemViewTest, HasCorrectCellularSublabel) {
                 IDS_ASH_STATUS_TRAY_NETWORK_STATUS_ACTIVATE_AFTER_DEVICE_SETUP),
             network_list_network_item_view()->sub_text_label()->GetText());
 
-  CreateUserSessions(/*session_count=*/1);
+  SimulateUserLogin(kDefaultUserEmail);
   base::RunLoop().RunUntilIdle();
 
   // Label for unactivated eSIM networks.
@@ -456,7 +456,7 @@ TEST_F(NetworkListNetworkItemViewTest, HasExpectedA11yText) {
           base::UTF8ToUTF16(kCellularName)),
       network_list_network_item_view()->GetViewAccessibility().GetCachedName());
 
-  CreateUserSessions(/*session_count=*/1);
+  SimulateUserLogin(kDefaultUserEmail);
   base::RunLoop().RunUntilIdle();
 
   // Contact carrier A11Y label is shown when a eSIM network is connected but
@@ -593,7 +593,7 @@ TEST_F(NetworkListNetworkItemViewTest, HasExpectedDescriptionForCellular) {
       l10n_util::GetStringUTF16(
           IDS_ASH_STATUS_TRAY_NETWORK_STATUS_ACTIVATE_AFTER_DEVICE_SETUP));
 
-  CreateUserSessions(/*session_count=*/1);
+  SimulateUserLogin(kDefaultUserEmail);
   base::RunLoop().RunUntilIdle();
 
   // Cellular is not activated and is an eSIM network.

ash/system/overview/overview_button_tray_unittest.cc

@@ -296,7 +296,7 @@ TEST_F(OverviewButtonTrayTest, VisibilityChangesForLoginStatus) {
   ClearLogin();
   Shell::Get()->UpdateAfterLoginStatusChange(LoginStatus::NOT_LOGGED_IN);
   EXPECT_FALSE(GetTray()->GetVisible());
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   Shell::Get()->UpdateAfterLoginStatusChange(LoginStatus::USER);
   EXPECT_TRUE(GetTray()->GetVisible());
   SetUserAddingScreenRunning(true);

ash/system/power/power_button_controller_unittest.cc

@@ -836,7 +836,7 @@ TEST_F(PowerButtonControllerTest, MenuItemsToLoginAndLockedStatus) {
   // Should have sign out, lock screen and feedback items if user is logged in
   // and screen is unlocked.
   ClearLogin();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   OpenPowerButtonMenu();
   EXPECT_FALSE(GetLockedState());
   EXPECT_TRUE(power_button_test_api_->MenuHasSignOutItem());
@@ -1034,7 +1034,7 @@ TEST_F(PowerButtonControllerTest, MenuNavigation) {
   TapToDismissPowerButtonMenu();
 
   ClearLogin();
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   OpenPowerButtonMenu();
   ASSERT_TRUE(power_button_test_api_->MenuHasSignOutItem());
   ASSERT_TRUE(power_button_test_api_->MenuHasLockScreenItem());

ash/system/power/power_button_test_base.cc

@@ -109,7 +109,7 @@ void PowerButtonTestBase::Initialize(
   if (status == LoginStatus::NOT_LOGGED_IN)
     ClearLogin();
   else
-    CreateUserSessions(1);
+    SimulateUserLogin(kDefaultUserEmail);
 
   if (status == LoginStatus::GUEST)
     SetCanLockScreen(false);

ash/system/session/logout_confirmation_controller_unittest.cc

@@ -221,7 +221,7 @@ TEST_F(LastWindowClosedTest, RegularSession) {
   EXPECT_FALSE(controller->dialog_for_testing());
 
   // Dialog is not visible after login.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_FALSE(controller->dialog_for_testing());
 
   // Creating and closing a window does not show the dialog because this is not

ash/system/session/session_limit_notification_controller_unittest.cc

@@ -183,7 +183,7 @@ TEST_F(SessionLimitNotificationControllerLoginTest,
   EXPECT_FALSE(GetNotification());
 
   // Notification is shown after login.
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_TRUE(GetNotification());
 
   RemoveNotification();
@@ -196,7 +196,7 @@ TEST_F(SessionLimitNotificationControllerLoginTest,
 
   // Notification should be absent.
   UpdateSessionLengthLimitInMin(kNotificationThresholdInMinutes + 10);
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   EXPECT_FALSE(GetNotification());
 
   RemoveNotification();

ash/system/unified/power_button_pixeltest.cc

@@ -65,7 +65,7 @@ TEST_F(PowerButtonPixelTest, DISABLED_NoSession) {
 
 // TODO(crbug.com/1451244): Re-enable this test.
 TEST_F(PowerButtonPixelTest, DISABLED_LoginSession) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   EXPECT_TRUE(GetPixelDiffer()->CompareUiComponentsOnPrimaryScreen(
       "check_button",
@@ -79,7 +79,7 @@ TEST_F(PowerButtonPixelTest, DISABLED_LoginSession) {
 
 // TODO(crbug.com/1451244): Re-enable this test.
 TEST_F(PowerButtonPixelTest, DISABLED_LockScreenSession) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   BlockUserSession(BLOCKED_BY_LOCK_SCREEN);
 
   EXPECT_TRUE(GetPixelDiffer()->CompareUiComponentsOnPrimaryScreen(

ash/system/unified/power_button_unittest.cc

@@ -148,7 +148,7 @@ class PowerButtonTest : public NoSessionAshTestBase {
 // `PowerButton` should be with the correct view id and have the UMA tracking
 // with the correct catalog name.
 TEST_F(PowerButtonTest, PowerButtonHasCorrectViewIdAndUma) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // No metrics logged before clicking on any buttons.
   histogram_tester_.ExpectTotalCount("Ash.QuickSettings.Button.Activated",
@@ -170,7 +170,9 @@ TEST_F(PowerButtonTest, PowerButtonHasCorrectViewIdAndUma) {
 }
 
 TEST_F(PowerButtonTest, LockMenuButtonRecordsUma) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
+  // TOOD(crbug.com/383442863): Move this to SimulateUserLogin.
+  GetSessionControllerClient()->SetCanLockScreen(true);
   SimulatePowerButtonPress();
 
   LeftClickOn(GetLockButton());
@@ -184,7 +186,7 @@ TEST_F(PowerButtonTest, LockMenuButtonRecordsUma) {
 }
 
 TEST_F(PowerButtonTest, SignOutMenuButtonRecordsUma) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SimulatePowerButtonPress();
 
   LeftClickOn(GetSignOutButton());
@@ -199,7 +201,7 @@ TEST_F(PowerButtonTest, SignOutMenuButtonRecordsUma) {
 }
 
 TEST_F(PowerButtonTest, RestartMenuButtonRecordsUma) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SimulatePowerButtonPress();
 
   LeftClickOn(GetRestartButton());
@@ -214,7 +216,7 @@ TEST_F(PowerButtonTest, RestartMenuButtonRecordsUma) {
 }
 
 TEST_F(PowerButtonTest, PowerOffMenuButtonRecordsUma) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SimulatePowerButtonPress();
 
   LeftClickOn(GetPowerOffButton());
@@ -228,7 +230,7 @@ TEST_F(PowerButtonTest, PowerOffMenuButtonRecordsUma) {
 }
 
 TEST_F(PowerButtonTest, EmailMenuButtonRecordsUma) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SimulatePowerButtonPress();
 
   LeftClickOn(GetEmailButton());
@@ -269,7 +271,9 @@ TEST_F(PowerButtonTest, ButtonStatesNotLoggedIn) {
 
 // All buttons are shown after login.
 TEST_F(PowerButtonTest, ButtonStatesLoggedIn) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
+  // TOOD(crbug.com/383442863): Move this to SimulateUserLogin.
+  GetSessionControllerClient()->SetCanLockScreen(true);
 
   EXPECT_TRUE(GetPowerButton()->GetVisible());
 
@@ -297,7 +301,7 @@ TEST_F(PowerButtonTest, ButtonStatesLoggedIn) {
 
 // The lock button are hidden at the lock screen.
 TEST_F(PowerButtonTest, ButtonStatesLockScreen) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   BlockUserSession(BLOCKED_BY_LOCK_SCREEN);
 
   // Changes in lock state close the system tray bubble, so re-show it.
@@ -331,7 +335,7 @@ TEST_F(PowerButtonTest, ButtonStatesLockScreen) {
 
 // The lock button is hidden when adding a second multiprofile user.
 TEST_F(PowerButtonTest, ButtonStatesAddingUser) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUserAddingScreenRunning(true);
 
   EXPECT_TRUE(GetPowerButton()->GetVisible());
@@ -450,7 +454,7 @@ TEST_F(PowerButtonTest, UserItemButtonTooltipText) {
 // Power button's rounded radii should change correctly when switching between
 // active/inactive.
 TEST_F(PowerButtonTest, ButtonRoundedRadii) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // Sets a LTR locale.
   base::i18n::SetICUDefaultLocale("en_US");
@@ -483,7 +487,7 @@ TEST_F(PowerButtonTest, ButtonRoundedRadii) {
 }
 
 TEST_F(PowerButtonTest, DeviceRebootOnShutdownPolicyHidesPowerOffButton) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   // Simulate DeviceRebootOnShutdownPolicy is enabled.
   Shell::Get()->shutdown_controller()->SetRebootOnShutdown(true);
 
@@ -494,7 +498,7 @@ TEST_F(PowerButtonTest, DeviceRebootOnShutdownPolicyHidesPowerOffButton) {
 }
 
 TEST_F(PowerButtonTest, ChevronFlipsWhenMenuIsShowing) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   EXPECT_TRUE(GetPowerButton()->GetVisible());
   EXPECT_FALSE(IsMenuShowing());

ash/system/unified/quick_settings_footer_unittest.cc

@@ -81,7 +81,9 @@ class QuickSettingsFooterTest : public NoSessionAshTestBase {
 // Tests that all buttons are with the correct view id, catalog name and UMA
 // tracking.
 TEST_F(QuickSettingsFooterTest, ButtonNamesAndUMA) {
-  CreateUserSessions(2);
+  auto primary = SimulateUserLogin(kDefaultUserEmail);
+  SimulateUserLogin(kDefaultUserEmail);
+  SwitchActiveUser(primary);
   SetUpView();
 
   // The number of view id should be the number of catalog name -1, since
@@ -141,7 +143,7 @@ TEST_F(QuickSettingsFooterTest, ButtonStatesNotLoggedIn) {
 
 // All buttons are shown after login.
 TEST_F(QuickSettingsFooterTest, ButtonStatesLoggedIn) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpView();
 
   EXPECT_FALSE(GetSignOutButton());
@@ -180,7 +182,7 @@ TEST_F(QuickSettingsFooterTest, ButtonStatesLockScreen) {
 // Settings button and lock button are hidden when adding a second
 // multiprofile user.
 TEST_F(QuickSettingsFooterTest, ButtonStatesAddingUser) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUserAddingScreenRunning(true);
   SetUpView();
 
@@ -233,7 +235,7 @@ TEST_F(QuickSettingsFooterTest, ButtonStatesPublicAccount) {
 
 TEST_F(QuickSettingsFooterTest, SignOutShowsWithMultipleAccounts) {
   GetSessionControllerClient()->set_existing_users_count(2);
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpView();
 
   ASSERT_TRUE(GetSignOutButton());
@@ -252,7 +254,7 @@ TEST_F(QuickSettingsFooterTest, SignOutButtonRecordsUmaAndSignsOut) {
   }
 
   GetSessionControllerClient()->set_existing_users_count(2);
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpView();
 
   base::HistogramTester histogram_tester;
@@ -285,7 +287,7 @@ TEST_F(QuickSettingsFooterTest, DisableSettingsIconPolicy) {
 
 // Tests different battery states.
 TEST_F(QuickSettingsFooterTest, BatteryButtonState) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpView();
 
   const bool use_smart_charging_ui =
@@ -313,7 +315,7 @@ TEST_F(QuickSettingsFooterTest, ButtonLayoutNotLoggedIn) {
 
 // Try to layout buttons after login.
 TEST_F(QuickSettingsFooterTest, ButtonLayoutLoggedIn) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpView();
   LayoutFooter();
 }
@@ -327,7 +329,7 @@ TEST_F(QuickSettingsFooterTest, ButtonLayoutLockScreen) {
 
 // Try to layout buttons when adding a second multiprofile user.
 TEST_F(QuickSettingsFooterTest, ButtonLayoutAddingUser) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUserAddingScreenRunning(true);
   SetUpView();
   LayoutFooter();

ash/system/unified/quiet_mode_feature_pod_controller_unittest.cc

@@ -78,14 +78,14 @@ TEST_F(QuietModeFeaturePodControllerTest, ButtonVisibilityNotLoggedIn) {
 }
 
 TEST_F(QuietModeFeaturePodControllerTest, ButtonVisibilityLoggedIn) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpButton();
   // If logged in, it should be visible.
   EXPECT_TRUE(IsButtonVisible());
 }
 
 TEST_F(QuietModeFeaturePodControllerTest, ButtonVisibilityLocked) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   BlockUserSession(UserSessionBlockReason::BLOCKED_BY_LOCK_SCREEN);
   SetUpButton();
   // If locked, it should not be visible.
@@ -93,7 +93,7 @@ TEST_F(QuietModeFeaturePodControllerTest, ButtonVisibilityLocked) {
 }
 
 TEST_F(QuietModeFeaturePodControllerTest, IconUMATracking) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
   SetUpButton();
   message_center::MessageCenter::Get()->SetQuietMode(false);
 
@@ -135,7 +135,7 @@ TEST_F(QuietModeFeaturePodControllerTest, IconUMATracking) {
 }
 
 TEST_F(QuietModeFeaturePodControllerTest, ToggledState) {
-  CreateUserSessions(1);
+  SimulateUserLogin(kDefaultUserEmail);
 
   // Do not disturb is initially off, button is not toggled.
   SetUpButton();

ash/test/ash_test_base.cc

@@ -427,13 +427,11 @@ AmbientAshTestHelper* AshTestBase::GetAmbientAshTestHelper() {
   return ash_test_helper_->ambient_ash_test_helper();
 }
 
-void AshTestBase::CreateUserSessions(int n) {
-  GetSessionControllerClient()->CreatePredefinedUserSessions(n);
-}
-
-void AshTestBase::SimulateUserLogin(const std::string& user_email,
-                                    user_manager::UserType user_type) {
-  SimulateUserLogin(AccountId::FromUserEmail(user_email), user_type);
+AccountId AshTestBase::SimulateUserLogin(const std::string& user_email,
+                                         user_manager::UserType user_type) {
+  auto account_id = AccountId::FromUserEmail(user_email);
+  SimulateUserLogin(account_id, user_type);
+  return account_id;
 }
 
 void AshTestBase::SimulateUserLogin(const AccountId& account_id,
@@ -441,10 +439,13 @@ void AshTestBase::SimulateUserLogin(const AccountId& account_id,
   ash_test_helper_->SimulateUserLogin(account_id, user_type);
 }
 
-void AshTestBase::SimulateNewUserFirstLogin(const std::string& user_email) {
-  ash_test_helper_->SimulateUserLogin(AccountId::FromUserEmail(user_email),
+AccountId AshTestBase::SimulateNewUserFirstLogin(
+    const std::string& user_email) {
+  auto account_id = AccountId::FromUserEmail(user_email);
+  ash_test_helper_->SimulateUserLogin(account_id,
                                       user_manager::UserType::kRegular,
                                       /*is_new_profile=*/true);
+  return account_id;
 }
 
 void AshTestBase::SimulateGuestLogin() {
@@ -460,6 +461,14 @@ void AshTestBase::SimulateKioskMode(user_manager::UserType user_type) {
   SimulateUserLogin(AccountId::FromUserEmail(kKioskUserEmail), user_type);
 }
 
+void AshTestBase::SwitchActiveUser(const AccountId& account_id) {
+  Shell::Get()->session_controller()->SwitchActiveUser(account_id);
+}
+
+bool AshTestBase::IsInSessionState(session_manager::SessionState state) const {
+  return Shell::Get()->session_controller()->GetSessionState() == state;
+}
+
 void AshTestBase::SetAccessibilityPanelHeight(int panel_height) {
   Shell::GetPrimaryRootWindowController()
       ->GetAccessibilityPanelLayoutManagerForTest()
@@ -488,7 +497,6 @@ void AshTestBase::SetUserAddingScreenRunning(bool user_adding_screen_running) {
 void AshTestBase::BlockUserSession(UserSessionBlockReason block_reason) {
   switch (block_reason) {
     case BLOCKED_BY_LOCK_SCREEN:
-      CreateUserSessions(1);
       GetSessionControllerClient()->LockScreen();
       break;
     case BLOCKED_BY_LOGIN_SCREEN:
@@ -503,7 +511,6 @@ void AshTestBase::BlockUserSession(UserSessionBlockReason block_reason) {
 }
 
 void AshTestBase::UnblockUserSession() {
-  CreateUserSessions(1);
   GetSessionControllerClient()->UnlockScreen();
 }
 

ash/test/ash_test_base.h

@@ -76,6 +76,8 @@ class TestSystemTrayClient;
 class UnifiedSystemTray;
 class WorkAreaInsets;
 
+inline constexpr std::string kDefaultUserEmail = "user0@tray";
+
 // Base class for most tests in //ash. Constructs ash::Shell and all its
 // dependencies. Provides a user login session (use NoSessionAshTestBase for
 // tests that start at the login screen or need unusual user types). Sets
@@ -310,18 +312,15 @@ class AshTestBase : public testing::Test {
 
   AmbientAshTestHelper* GetAmbientAshTestHelper();
 
-  // Emulates an ash session that have |session_count| user sessions running.
-  // Note that existing user sessions will be cleared.
-  void CreateUserSessions(int session_count);
-
-  // Simulates a user sign-in. It creates a new user session, adds it to
-  // existing user sessions and makes it the active user session.
+  // Simulates a user sign-in, and returns an AccountId used to sign in.  It
+  // creates a new user session, adds it to existing user sessions and makes it
+  // the active user session.
   //
   // For convenience |user_email| is used to create an |AccountId|. For testing
   // behavior where |AccountId|s are compared, prefer the method of the same
   // name that takes an |AccountId| created with a valid storage key instead.
   // See the documentation for|AccountId::GetUserEmail| for discussion.
-  void SimulateUserLogin(
+  AccountId SimulateUserLogin(
       const std::string& user_email,
       user_manager::UserType user_type = user_manager::UserType::kRegular);
 
@@ -332,7 +331,7 @@ class AshTestBase : public testing::Test {
       user_manager::UserType user_type = user_manager::UserType::kRegular);
 
   // Simular to SimulateUserLogin but for a newly created user first ever login.
-  void SimulateNewUserFirstLogin(const std::string& user_email);
+  AccountId SimulateNewUserFirstLogin(const std::string& user_email);
 
   // Similar to SimulateUserLogin but for a guest user.
   void SimulateGuestLogin();
@@ -340,6 +339,12 @@ class AshTestBase : public testing::Test {
   // Simulates kiosk mode. |user_type| must correlate to a kiosk type user.
   void SimulateKioskMode(user_manager::UserType user_type);
 
+  // Switches the active user to `account_id`;
+  void SwitchActiveUser(const AccountId& account_id);
+
+  // Returns true if the session is in `state`.
+  bool IsInSessionState(session_manager::SessionState state) const;
+
   // Simulates setting height of the accessibility panel.
   // Note: Accessibility panel widget needs to be setup first.
   void SetAccessibilityPanelHeight(int panel_height);
@@ -358,6 +363,7 @@ class AshTestBase : public testing::Test {
 
   // Methods to emulate blocking and unblocking user session with given
   // |block_reason|.
+  // TODO(crbug.com/383770001): Deprecate these methods.
   void BlockUserSession(UserSessionBlockReason block_reason);
   void UnblockUserSession();
 

ash/test/ash_test_helper.cc

@@ -398,9 +398,6 @@ void AshTestHelper::SetUp(InitParams init_params) {
   session_controller_client_ = std::make_unique<TestSessionControllerClient>(
       shell->session_controller(), prefs_provider_.get());
   session_controller_client_->InitializeAndSetClient();
-  if (init_params.start_session) {
-    session_controller_client_->CreatePredefinedUserSessions(1);
-  }
 
   // Requires the AppListController the Shell creates.
   app_list_test_helper_ = std::make_unique<AppListTestHelper>();
@@ -408,6 +405,21 @@ void AshTestHelper::SetUp(InitParams init_params) {
   Shell::GetPrimaryRootWindow()->Show();
   Shell::GetPrimaryRootWindow()->GetHost()->Show();
 
+  // Sign-in after UI is shown.
+  if (init_params.start_session) {
+    // TODO(crbug.com/383441831): Remove Reset();
+    session_controller_client_->Reset();
+
+    auto account_id = AccountId::FromUserEmail("user0@tray");
+    // TODO((crbug.com/383441831): Use SimulateUserLogin.
+    session_controller_client_->AddUserSession(
+        account_id, account_id.GetUserEmail(),
+        user_manager::UserType::kRegular);
+    session_controller_client_->SwitchActiveUser(account_id);
+    session_controller_client_->SetSessionState(
+        session_manager::SessionState::ACTIVE);
+  }
+
   // Don't change the display size due to host size resize.
   display::test::DisplayManagerTestApi(shell->display_manager())
       .DisableChangeDisplayUponHostResize();

chrome/browser/ash/mahi/mahi_manager_impl_unittest.cc

@@ -148,7 +148,7 @@ class MahiManagerImplTest : public NoSessionAshTestBase {
     mahi_manager_impl_ = std::make_unique<MahiManagerImpl>();
     mahi_manager_impl_->mahi_provider_ = CreateMahiProvider();
 
-    CreateUserSessions(1);
+    SimulateUserLogin(kDefaultUserEmail);
   }
 
   void TearDown() override {

chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl_unittest.cc

@@ -34,7 +34,9 @@
 class AssistantBrowserDelegateImplTest : public ChromeAshTestBase {
  public:
   AssistantBrowserDelegateImplTest()
-      : fake_user_manager_(std::make_unique<ash::FakeChromeUserManager>()) {}
+      : fake_user_manager_(std::make_unique<ash::FakeChromeUserManager>()) {
+    set_start_session(false);
+  }
   ~AssistantBrowserDelegateImplTest() override = default;
 
   void SetUp() override {
@@ -46,7 +48,6 @@ class AssistantBrowserDelegateImplTest : public ChromeAshTestBase {
     auto* user = fake_user_manager_->AddUser(account_id);
     fake_user_manager_->LoginUser(account_id);
 
-    CreateUserSessions(/*session_count=*/1);
     SimulateUserLogin(account_id);
 
     ash::ProfileHelper::Get()->SetUserToProfileMappingForTesting(

chrome/browser/ui/ash/quick_answers/test/chrome_quick_answers_test_base.cc

@@ -20,7 +20,9 @@
 #include "ui/views/controls/menu/menu_runner.h"
 #include "ui/views/widget/widget.h"
 
-ChromeQuickAnswersTestBase::ChromeQuickAnswersTestBase() = default;
+ChromeQuickAnswersTestBase::ChromeQuickAnswersTestBase() {
+  set_start_session(false);
+}
 
 ChromeQuickAnswersTestBase::~ChromeQuickAnswersTestBase() = default;
 
@@ -38,11 +40,11 @@ void ChromeQuickAnswersTestBase::SetUp() {
   GetFakeUserManager()->AddUser(account_id);
   GetFakeUserManager()->LoginUser(account_id);
 
+  SimulateUserLogin(account_id);
+
   SetUpInitialPrefValues();
   quick_answers_controller_ =
       CreateQuickAnswersControllerImpl(read_write_cards_ui_controller_);
-
-  CreateUserSessions(/*session_count=*/1);
 }
 
 void ChromeQuickAnswersTestBase::TearDown() {

components/exo/keyboard_unittest.cc

@@ -1183,7 +1183,9 @@ TEST_F(KeyboardTest, KeyRepeatSettingsUpdateAtRuntime) {
 
 TEST_F(KeyboardTest, KeyRepeatSettingsIgnoredForNonActiveUser) {
   // Simulate two users, with the first user as active.
-  CreateUserSessions(2);
+  auto active_account_id = SimulateUserLogin("user0@gmail.com");
+  auto inactive_account_id = SimulateUserLogin("user1@gmail.com");
+  SwitchActiveUser(active_account_id);
 
   // Key repeat settings should be sent exactly once, for the default values.
   auto delegate = std::make_unique<NiceMockKeyboardDelegate>();
@@ -1198,7 +1200,7 @@ TEST_F(KeyboardTest, KeyRepeatSettingsIgnoredForNonActiveUser) {
   EXPECT_CALL(*delegate_ptr,
               OnKeyRepeatSettingsChanged(testing::_, testing::_, testing::_))
       .Times(0);
-  const std::string email = "user1@tray";
+  const auto email = inactive_account_id.GetUserEmail();
   SetUserPref(email, ash::prefs::kXkbAutoRepeatEnabled, base::Value(true));
   SetUserPref(email, ash::prefs::kXkbAutoRepeatDelay, base::Value(1000));
   SetUserPref(email, ash::prefs::kXkbAutoRepeatInterval, base::Value(1000));
@@ -1207,10 +1209,12 @@ TEST_F(KeyboardTest, KeyRepeatSettingsIgnoredForNonActiveUser) {
 
 TEST_F(KeyboardTest, KeyRepeatSettingsUpdateOnProfileChange) {
   // Simulate two users, with the first user as active.
-  CreateUserSessions(2);
+  auto active_account_id = SimulateUserLogin("user0@gmail.com");
+  auto inactive_account_id = SimulateUserLogin("user1@gmail.com");
+  SwitchActiveUser(active_account_id);
 
   // Second user has different preferences.
-  std::string email = "user1@tray";
+  std::string email = inactive_account_id.GetUserEmail();
   SetUserPref(email, ash::prefs::kXkbAutoRepeatEnabled, base::Value(true));
   SetUserPref(email, ash::prefs::kXkbAutoRepeatDelay, base::Value(1000));
   SetUserPref(email, ash::prefs::kXkbAutoRepeatInterval, base::Value(1000));