Migrate //chromeos/ash/services/assistant to namespace ash [2/N]

This CL migrates public/cpp to namespace ash from chromeos. To avoid
conflicts with internal sources, this CL has temporary 'using'
declarations.

This CL is part of the Chrome OS source code directory migration:
https://docs.google.com/document/d/1g-98HpzA8XcoGBWUv1gQNr4rbnD5yfvbtYZyPDDbkaE.

Change-Id: I4e406d2a446c0bfe9f24fdfe9f3feab9e6026eff
Bug: 1164001
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3789017
Reviewed-by: Tao Wu <[email protected]>
Commit-Queue: Yeunjoo Choi <[email protected]>
Reviewed-by: Hidehiko Abe <[email protected]>
Owners-Override: Hidehiko Abe <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1030408}
diff --git a/ash/accelerators/accelerator_controller_impl.cc b/ash/accelerators/accelerator_controller_impl.cc
index 228a24c..66b3301 100644
--- a/ash/accelerators/accelerator_controller_impl.cc
+++ b/ash/accelerators/accelerator_controller_impl.cc
@@ -1002,7 +1002,7 @@
         base::UserMetricsAction("VoiceInteraction.Started.Assistant"));
   }
 
-  using chromeos::assistant::AssistantAllowedState;
+  using assistant::AssistantAllowedState;
   switch (AssistantState::Get()->allowed_state().value_or(
       AssistantAllowedState::ALLOWED)) {
     case AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER:
@@ -1057,8 +1057,8 @@
   }
 
   AssistantUiController::Get()->ToggleUi(
-      /*entry_point=*/chromeos::assistant::AssistantEntryPoint::kHotkey,
-      /*exit_point=*/chromeos::assistant::AssistantExitPoint::kHotkey);
+      /*entry_point=*/assistant::AssistantEntryPoint::kHotkey,
+      /*exit_point=*/assistant::AssistantExitPoint::kHotkey);
 }
 
 void HandleSuspend() {
diff --git a/ash/app_list/app_list_bubble_presenter.cc b/ash/app_list/app_list_bubble_presenter.cc
index 26a199f..e35288a 100644
--- a/ash/app_list/app_list_bubble_presenter.cc
+++ b/ash/app_list/app_list_bubble_presenter.cc
@@ -47,7 +47,7 @@
 namespace ash {
 namespace {
 
-using chromeos::assistant::AssistantExitPoint;
+using assistant::AssistantExitPoint;
 
 // Maximum amount of time to spend refreshing zero state search results before
 // opening the launcher.
diff --git a/ash/app_list/app_list_controller_impl.cc b/ash/app_list/app_list_controller_impl.cc
index 18f4ce0..e938dcd9 100644
--- a/ash/app_list/app_list_controller_impl.cc
+++ b/ash/app_list/app_list_controller_impl.cc
@@ -83,8 +83,8 @@
 
 namespace ash {
 
-using chromeos::assistant::AssistantEntryPoint;
-using chromeos::assistant::AssistantExitPoint;
+using assistant::AssistantEntryPoint;
+using assistant::AssistantExitPoint;
 
 namespace {
 
@@ -982,7 +982,7 @@
 }
 
 void AppListControllerImpl::OnAssistantStatusChanged(
-    chromeos::assistant::AssistantStatus status) {
+    assistant::AssistantStatus status) {
   UpdateAssistantVisibility();
 }
 
@@ -991,7 +991,7 @@
 }
 
 void AppListControllerImpl::OnAssistantFeatureAllowedChanged(
-    chromeos::assistant::AssistantAllowedState state) {
+    assistant::AssistantAllowedState state) {
   UpdateAssistantVisibility();
 }
 
@@ -1525,10 +1525,8 @@
 
   auto* state = AssistantState::Get();
   return state->settings_enabled().value_or(false) &&
-         state->allowed_state() ==
-             chromeos::assistant::AssistantAllowedState::ALLOWED &&
-         state->assistant_status() !=
-             chromeos::assistant::AssistantStatus::NOT_READY;
+         state->allowed_state() == assistant::AssistantAllowedState::ALLOWED &&
+         state->assistant_status() != assistant::AssistantStatus::NOT_READY;
 }
 
 bool AppListControllerImpl::ShouldShowSuggestedContentInfo() const {
diff --git a/ash/app_list/app_list_controller_impl.h b/ash/app_list/app_list_controller_impl.h
index 167380d..d494afb 100644
--- a/ash/app_list/app_list_controller_impl.h
+++ b/ash/app_list/app_list_controller_impl.h
@@ -250,11 +250,10 @@
   void OnWallpaperPreviewEnded() override;
 
   // AssistantStateObserver:
-  void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus status) override;
+  void OnAssistantStatusChanged(assistant::AssistantStatus status) override;
   void OnAssistantSettingsEnabled(bool enabled) override;
   void OnAssistantFeatureAllowedChanged(
-      chromeos::assistant::AssistantAllowedState state) override;
+      assistant::AssistantAllowedState state) override;
 
   // WindowTreeHostManager::Observer:
   void OnDisplayConfigurationChanged() override;
diff --git a/ash/app_list/app_list_controller_impl_unittest.cc b/ash/app_list/app_list_controller_impl_unittest.cc
index 80d1417..dbf2e64 100644
--- a/ash/app_list/app_list_controller_impl_unittest.cc
+++ b/ash/app_list/app_list_controller_impl_unittest.cc
@@ -1780,9 +1780,9 @@
 
     assistant_test_api_->SetAssistantEnabled(true);
     assistant_test_api_->GetAssistantState()->NotifyFeatureAllowed(
-        chromeos::assistant::AssistantAllowedState::ALLOWED);
+        assistant::AssistantAllowedState::ALLOWED);
     assistant_test_api_->GetAssistantState()->NotifyStatusChanged(
-        chromeos::assistant::AssistantStatus::READY);
+        assistant::AssistantStatus::READY);
     assistant_test_api_->WaitUntilIdle();
   }
 
diff --git a/ash/app_list/app_list_presenter_impl.cc b/ash/app_list/app_list_presenter_impl.cc
index 055a0b8d..f84aa1a 100644
--- a/ash/app_list/app_list_presenter_impl.cc
+++ b/ash/app_list/app_list_presenter_impl.cc
@@ -51,7 +51,7 @@
 namespace ash {
 namespace {
 
-using chromeos::assistant::AssistantExitPoint;
+using assistant::AssistantExitPoint;
 
 inline ui::Layer* GetLayer(views::Widget* widget) {
   return widget->GetNativeView()->layer();
diff --git a/ash/app_list/views/app_list_bubble_view_unittest.cc b/ash/app_list/views/app_list_bubble_view_unittest.cc
index 96337235..de1a671 100644
--- a/ash/app_list/views/app_list_bubble_view_unittest.cc
+++ b/ash/app_list/views/app_list_bubble_view_unittest.cc
@@ -505,7 +505,7 @@
   // Simulate the app list being closed by taking a screenshot with assistant.
   // This makes AppListControllerImpl::ShouldDismissImmediately() return true.
   AssistantUiController::Get()->ToggleUi(
-      absl::nullopt, chromeos::assistant::AssistantExitPoint::kScreenshot);
+      absl::nullopt, assistant::AssistantExitPoint::kScreenshot);
 
   // The bubble dismissed immediately so it is not animating.
   ui::Layer* bubble_layer = GetAppListTestHelper()->GetBubbleView()->layer();
diff --git a/ash/app_list/views/assistant/assistant_page_view_unittest.cc b/ash/app_list/views/assistant/assistant_page_view_unittest.cc
index 84dc1f5..c7b7450 100644
--- a/ash/app_list/views/assistant/assistant_page_view_unittest.cc
+++ b/ash/app_list/views/assistant/assistant_page_view_unittest.cc
@@ -244,7 +244,7 @@
 
 // Counts the number of Assistant interactions that are started.
 class AssistantInteractionCounter
-    : private chromeos::assistant::AssistantInteractionSubscriber {
+    : private assistant::AssistantInteractionSubscriber {
  public:
   explicit AssistantInteractionCounter(
       chromeos::assistant::Assistant* service) {
@@ -264,8 +264,7 @@
   }
 
   int interaction_count_ = 0;
-  chromeos::assistant::ScopedAssistantInteractionSubscriber
-      interaction_observer_{this};
+  assistant::ScopedAssistantInteractionSubscriber interaction_observer_{this};
 };
 
 TEST_F(AssistantPageNonBubbleTest, ShouldStartInPeekingState) {
diff --git a/ash/app_list/views/assistant/assistant_test_api_impl.cc b/ash/app_list/views/assistant/assistant_test_api_impl.cc
index f4d317f3..9d2bba4 100644
--- a/ash/app_list/views/assistant/assistant_test_api_impl.cc
+++ b/ash/app_list/views/assistant/assistant_test_api_impl.cc
@@ -143,15 +143,14 @@
 void AssistantTestApiImpl::EnableAssistantAndWait() {
   SetAssistantEnabled(true);
   GetAssistantState()->NotifyFeatureAllowed(
-      chromeos::assistant::AssistantAllowedState::ALLOWED);
-  GetAssistantState()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+      assistant::AssistantAllowedState::ALLOWED);
+  GetAssistantState()->NotifyStatusChanged(assistant::AssistantStatus::READY);
   WaitUntilIdle();
 }
 
 void AssistantTestApiImpl::SetAssistantEnabled(bool enabled) {
   Shell::Get()->session_controller()->GetPrimaryUserPrefService()->SetBoolean(
-      chromeos::assistant::prefs::kAssistantEnabled, enabled);
+      assistant::prefs::kAssistantEnabled, enabled);
 
   // Ensure the value has taken effect.
   ASSERT_EQ(GetAssistantState()->settings_enabled(), enabled)
@@ -162,7 +161,7 @@
 
 void AssistantTestApiImpl::SetScreenContextEnabled(bool enabled) {
   Shell::Get()->session_controller()->GetPrimaryUserPrefService()->SetBoolean(
-      chromeos::assistant::prefs::kAssistantContextEnabled, enabled);
+      assistant::prefs::kAssistantContextEnabled, enabled);
 
   // Ensure the value has taken effect.
   ASSERT_EQ(GetAssistantState()->context_enabled(), enabled)
@@ -181,9 +180,9 @@
 }
 
 void AssistantTestApiImpl::SetConsentStatus(
-    chromeos::assistant::prefs::ConsentStatus consent_status) {
+    assistant::prefs::ConsentStatus consent_status) {
   Shell::Get()->session_controller()->GetPrimaryUserPrefService()->SetInteger(
-      chromeos::assistant::prefs::kAssistantConsentStatus, consent_status);
+      assistant::prefs::kAssistantConsentStatus, consent_status);
 
   // Ensure the value has taken effect.
   ASSERT_EQ(GetAssistantState()->consent_status(), consent_status)
@@ -199,10 +198,10 @@
 }
 
 void AssistantTestApiImpl::SetOnboardingMode(
-    chromeos::assistant::prefs::AssistantOnboardingMode onboarding_mode) {
+    assistant::prefs::AssistantOnboardingMode onboarding_mode) {
   Shell::Get()->session_controller()->GetPrimaryUserPrefService()->SetString(
-      chromeos::assistant::prefs::kAssistantOnboardingMode,
-      chromeos::assistant::prefs::ToOnboardingModeString(onboarding_mode));
+      assistant::prefs::kAssistantOnboardingMode,
+      assistant::prefs::ToOnboardingModeString(onboarding_mode));
 
   // Ensure the value has taken effect.
   ASSERT_EQ(GetAssistantState()->onboarding_mode(), onboarding_mode)
@@ -213,7 +212,7 @@
 
 void AssistantTestApiImpl::SetPreferVoice(bool value) {
   Shell::Get()->session_controller()->GetPrimaryUserPrefService()->SetBoolean(
-      chromeos::assistant::prefs::kAssistantLaunchWithMicOpen, value);
+      assistant::prefs::kAssistantLaunchWithMicOpen, value);
 
   // Ensure the value has taken effect.
   ASSERT_EQ(GetAssistantState()->launch_with_mic_open(), value)
diff --git a/ash/app_list/views/assistant/assistant_test_api_impl.h b/ash/app_list/views/assistant/assistant_test_api_impl.h
index 7ab994b..406946a 100644
--- a/ash/app_list/views/assistant/assistant_test_api_impl.h
+++ b/ash/app_list/views/assistant/assistant_test_api_impl.h
@@ -36,10 +36,9 @@
   void SetAssistantEnabled(bool enable) override;
   void SetScreenContextEnabled(bool enabled) override;
   void SetTabletMode(bool enable) override;
-  void SetConsentStatus(chromeos::assistant::prefs::ConsentStatus) override;
+  void SetConsentStatus(assistant::prefs::ConsentStatus) override;
   void SetNumberOfSessionsWhereOnboardingShown(int number_of_sessions) override;
-  void SetOnboardingMode(
-      chromeos::assistant::prefs::AssistantOnboardingMode) override;
+  void SetOnboardingMode(assistant::prefs::AssistantOnboardingMode) override;
   void SetPreferVoice(bool value) override;
   void SetTimeOfLastInteraction(base::Time time) override;
   void StartOverview() override;
diff --git a/ash/ash_prefs.cc b/ash/ash_prefs.cc
index 9199866..2aa3f05 100644
--- a/ash/ash_prefs.cc
+++ b/ash/ash_prefs.cc
@@ -117,7 +117,7 @@
 
   // Provide prefs registered in the browser for ash_unittests.
   if (for_test) {
-    chromeos::assistant::prefs::RegisterProfilePrefs(registry);
+    assistant::prefs::RegisterProfilePrefs(registry);
     quick_answers::prefs::RegisterProfilePrefs(registry);
     registry->RegisterBooleanPref(prefs::kMouseReverseScroll, false);
     registry->RegisterBooleanPref(prefs::kSendFunctionKeys, false);
diff --git a/ash/assistant/assistant_alarm_timer_controller_impl.cc b/ash/assistant/assistant_alarm_timer_controller_impl.cc
index dbb70ff7..7af3daba 100644
--- a/ash/assistant/assistant_alarm_timer_controller_impl.cc
+++ b/ash/assistant/assistant_alarm_timer_controller_impl.cc
@@ -293,7 +293,7 @@
 }
 
 void AssistantAlarmTimerControllerImpl::SetAssistant(
-    chromeos::assistant::Assistant* assistant) {
+    assistant::Assistant* assistant) {
   assistant_ = assistant;
 }
 
@@ -361,10 +361,10 @@
 }
 
 void AssistantAlarmTimerControllerImpl::OnAssistantStatusChanged(
-    chromeos::assistant::AssistantStatus status) {
+    assistant::AssistantStatus status) {
   // If LibAssistant is no longer running we need to clear our cache to
   // accurately reflect LibAssistant alarm/timer state.
-  if (status == chromeos::assistant::AssistantStatus::NOT_READY)
+  if (status == assistant::AssistantStatus::NOT_READY)
     model_.RemoveAllTimers();
 }
 
diff --git a/ash/assistant/assistant_alarm_timer_controller_impl.h b/ash/assistant/assistant_alarm_timer_controller_impl.h
index 97a2ddc..90c0340 100644
--- a/ash/assistant/assistant_alarm_timer_controller_impl.h
+++ b/ash/assistant/assistant_alarm_timer_controller_impl.h
@@ -49,7 +49,7 @@
   ~AssistantAlarmTimerControllerImpl() override;
 
   // Provides a pointer to the |assistant| owned by AssistantService.
-  void SetAssistant(chromeos::assistant::Assistant* assistant);
+  void SetAssistant(assistant::Assistant* assistant);
 
   // AssistantAlarmTimerController:
   const AssistantAlarmTimerModel* GetModel() const override;
@@ -64,8 +64,7 @@
       const std::map<std::string, std::string>& params) override;
 
   // AssistantStateObserver:
-  void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus status) override;
+  void OnAssistantStatusChanged(assistant::AssistantStatus status) override;
 
   // AssistantAlarmTimerModelObserver:
   void OnTimerAdded(const chromeos::assistant::AssistantTimer& timer) override;
@@ -91,7 +90,7 @@
   std::map<std::string, base::OneShotTimer> tickers_;
 
   // Owned by AssistantService.
-  chromeos::assistant::Assistant* assistant_;
+  assistant::Assistant* assistant_;
 
   base::ScopedObservation<AssistantController, AssistantControllerObserver>
       assistant_controller_observation_{this};
diff --git a/ash/assistant/assistant_controller_impl.cc b/ash/assistant/assistant_controller_impl.cc
index b4160d0..7d6de45 100644
--- a/ash/assistant/assistant_controller_impl.cc
+++ b/ash/assistant/assistant_controller_impl.cc
@@ -66,8 +66,7 @@
   assistant_volume_control_receiver_.Bind(std::move(receiver));
 }
 
-void AssistantControllerImpl::SetAssistant(
-    chromeos::assistant::Assistant* assistant) {
+void AssistantControllerImpl::SetAssistant(assistant::Assistant* assistant) {
   assistant_ = assistant;
 
   // Provide reference to sub-controllers.
@@ -175,7 +174,7 @@
   if (IsAndroidIntent(url)) {
     android_helper->LaunchAndroidIntent(url.spec());
   } else {
-    chromeos::assistant::AssistantBrowserDelegate::Get()->OpenUrl(url);
+    assistant::AssistantBrowserDelegate::Get()->OpenUrl(url);
   }
   NotifyUrlOpened(url, from_server);
 }
@@ -211,13 +210,13 @@
 
       // Close the assistant UI so that the feedback page is visible.
       assistant_ui_controller_.CloseUi(
-          chromeos::assistant::AssistantExitPoint::kUnspecified);
+          assistant::AssistantExitPoint::kUnspecified);
       break;
     case DeepLinkType::kScreenshot:
       // We close the UI before taking the screenshot as it's probably not the
       // user's intention to include the Assistant in the picture.
       assistant_ui_controller_.CloseUi(
-          chromeos::assistant::AssistantExitPoint::kScreenshot);
+          assistant::AssistantExitPoint::kScreenshot);
       CaptureModeController::Get()->CaptureScreenshotsOfAllDisplays();
       break;
     case DeepLinkType::kTaskManager:
@@ -326,16 +325,16 @@
 }
 
 void AssistantControllerImpl::OnAssistantStatusChanged(
-    chromeos::assistant::AssistantStatus status) {
-  if (status == chromeos::assistant::AssistantStatus::NOT_READY)
+    assistant::AssistantStatus status) {
+  if (status == assistant::AssistantStatus::NOT_READY)
     assistant_ui_controller_.CloseUi(
-        chromeos::assistant::AssistantExitPoint::kUnspecified);
+        assistant::AssistantExitPoint::kUnspecified);
 }
 
 void AssistantControllerImpl::OnLockedFullScreenStateChanged(bool enabled) {
   if (enabled)
     assistant_ui_controller_.CloseUi(
-        chromeos::assistant::AssistantExitPoint::kUnspecified);
+        assistant::AssistantExitPoint::kUnspecified);
 }
 
 void AssistantControllerImpl::BindVolumeControl(
diff --git a/ash/assistant/assistant_controller_impl.h b/ash/assistant/assistant_controller_impl.h
index ff87c222..e724fa1 100644
--- a/ash/assistant/assistant_controller_impl.h
+++ b/ash/assistant/assistant_controller_impl.h
@@ -81,7 +81,7 @@
   void OpenAssistantSettings() override;
   void OpenUrl(const GURL& url, bool in_background, bool from_server) override;
   base::WeakPtr<ash::AssistantController> GetWeakPtr() override;
-  void SetAssistant(chromeos::assistant::Assistant* assistant) override;
+  void SetAssistant(assistant::Assistant* assistant) override;
   void StartSpeakerIdEnrollmentFlow() override;
   void SendAssistantFeedback(bool assistant_debug_info_allowed,
                              const std::string& feedback_description,
@@ -140,8 +140,7 @@
   void NotifyUrlOpened(const GURL& url, bool from_server);
 
   // AssistantStateObserver:
-  void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus status) override;
+  void OnAssistantStatusChanged(assistant::AssistantStatus status) override;
   void OnLockedFullScreenStateChanged(bool enabled) override;
 
   // AssistantInterfaceBinder implementation:
@@ -158,7 +157,7 @@
 
   // |assistant_| can be nullptr if libassistant creation is not yet completed,
   // i.e. it cannot take a request.
-  chromeos::assistant::Assistant* assistant_ = nullptr;
+  assistant::Assistant* assistant_ = nullptr;
 
   // Assistant sub-controllers.
   AssistantAlarmTimerControllerImpl assistant_alarm_timer_controller_{this};
diff --git a/ash/assistant/assistant_interaction_controller_impl.cc b/ash/assistant/assistant_interaction_controller_impl.cc
index 2ce8919..fb18275 100644
--- a/ash/assistant/assistant_interaction_controller_impl.cc
+++ b/ash/assistant/assistant_interaction_controller_impl.cc
@@ -44,7 +44,7 @@
 
 namespace {
 
-using chromeos::assistant::features::IsWaitSchedulingEnabled;
+using assistant::features::IsWaitSchedulingEnabled;
 
 // Android.
 constexpr char kAndroidIntentScheme[] = "intent://";
diff --git a/ash/assistant/assistant_interaction_controller_impl.h b/ash/assistant/assistant_interaction_controller_impl.h
index 6426fc0..cf1c833 100644
--- a/ash/assistant/assistant_interaction_controller_impl.h
+++ b/ash/assistant/assistant_interaction_controller_impl.h
@@ -34,7 +34,7 @@
 
 class AssistantInteractionControllerImpl
     : public AssistantInteractionController,
-      public chromeos::assistant::AssistantInteractionSubscriber,
+      public assistant::AssistantInteractionSubscriber,
       public AssistantControllerObserver,
       public AssistantInteractionModelObserver,
       public AssistantUiModelObserver,
@@ -45,7 +45,7 @@
   using AssistantInteractionMetadata =
       chromeos::assistant::AssistantInteractionMetadata;
   using AssistantInteractionResolution =
-      chromeos::assistant::AssistantInteractionResolution;
+      assistant::AssistantInteractionResolution;
   using AssistantInteractionType =
       chromeos::assistant::AssistantInteractionType;
   using AssistantQuerySource = chromeos::assistant::AssistantQuerySource;
@@ -65,7 +65,7 @@
   static void RegisterProfilePrefs(PrefRegistrySimple* registry);
 
   // Provides a pointer to the |assistant| owned by AssistantService.
-  void SetAssistant(chromeos::assistant::Assistant* assistant);
+  void SetAssistant(assistant::Assistant* assistant);
 
   // AssistantInteractionController:
   const AssistantInteractionModel* GetModel() const override;
@@ -98,7 +98,7 @@
   // HighlighterController::Observer:
   void OnHighlighterSelectionRecognized(const gfx::Rect& rect) override;
 
-  // chromeos::assistant::AssistantInteractionSubscriber:
+  // assistant::AssistantInteractionSubscriber:
   void OnInteractionStarted(
       const AssistantInteractionMetadata& metadata) override;
   void OnInteractionFinished(
@@ -150,7 +150,7 @@
   bool has_had_interaction_ = false;
 
   // Owned by AssistantService.
-  chromeos::assistant::Assistant* assistant_ = nullptr;
+  assistant::Assistant* assistant_ = nullptr;
 
   base::ScopedObservation<AssistantController, AssistantControllerObserver>
       assistant_controller_observation_{this};
diff --git a/ash/assistant/assistant_interaction_controller_impl_unittest.cc b/ash/assistant/assistant_interaction_controller_impl_unittest.cc
index 270f762..e988be84 100644
--- a/ash/assistant/assistant_interaction_controller_impl_unittest.cc
+++ b/ash/assistant/assistant_interaction_controller_impl_unittest.cc
@@ -36,16 +36,16 @@
 
 namespace {
 
+using assistant::AssistantInteractionSubscriber;
+using assistant::ScopedAssistantInteractionSubscriber;
 using chromeos::assistant::AndroidAppInfo;
 using chromeos::assistant::Assistant;
 using chromeos::assistant::AssistantInteractionMetadata;
-using chromeos::assistant::AssistantInteractionSubscriber;
 using chromeos::assistant::AssistantInteractionType;
 using chromeos::assistant::AssistantQuerySource;
 using chromeos::assistant::AssistantSuggestion;
 using chromeos::assistant::AssistantSuggestionType;
 using chromeos::assistant::MockAssistantInteractionSubscriber;
-using chromeos::assistant::ScopedAssistantInteractionSubscriber;
 
 using ::testing::Invoke;
 using ::testing::Mock;
@@ -55,7 +55,7 @@
 // Mocks -----------------------------------------------------------------------
 
 class AssistantInteractionSubscriberMock
-    : public chromeos::assistant::AssistantInteractionSubscriber {
+    : public AssistantInteractionSubscriber {
  public:
   explicit AssistantInteractionSubscriberMock(Assistant* service) {
     scoped_subscriber_.Observe(service);
@@ -69,8 +69,7 @@
               (override));
 
  private:
-  chromeos::assistant::ScopedAssistantInteractionSubscriber scoped_subscriber_{
-      this};
+  ScopedAssistantInteractionSubscriber scoped_subscriber_{this};
 };
 
 // AssistantInteractionControllerImplTest --------------------------------------
@@ -237,7 +236,7 @@
   base::RunLoop().RunUntilIdle();
 
   interaction_controller()->OnInteractionFinished(
-      chromeos::assistant::AssistantInteractionResolution::kError);
+      assistant::AssistantInteractionResolution::kError);
 
   base::RunLoop().RunUntilIdle();
 
diff --git a/ash/assistant/assistant_notification_controller_impl.cc b/ash/assistant/assistant_notification_controller_impl.cc
index 77f417b..f0bc333 100644
--- a/ash/assistant/assistant_notification_controller_impl.cc
+++ b/ash/assistant/assistant_notification_controller_impl.cc
@@ -98,7 +98,7 @@
 }
 
 void AssistantNotificationControllerImpl::SetAssistant(
-    chromeos::assistant::Assistant* assistant) {
+    assistant::Assistant* assistant) {
   receiver_.reset();
 
   assistant_ = assistant;
diff --git a/ash/assistant/assistant_notification_controller_impl.h b/ash/assistant/assistant_notification_controller_impl.h
index 002db1b..2cf57388 100644
--- a/ash/assistant/assistant_notification_controller_impl.h
+++ b/ash/assistant/assistant_notification_controller_impl.h
@@ -44,7 +44,7 @@
   const AssistantNotificationModel* model() const { return &model_; }
 
   // Provides a pointer to the |assistant| owned by AssistantController.
-  void SetAssistant(chromeos::assistant::Assistant* assistant);
+  void SetAssistant(assistant::Assistant* assistant);
 
   // AssistantNotificationController:
   void RemoveNotificationById(const std::string& id, bool from_server) override;
@@ -79,7 +79,7 @@
   AssistantNotificationExpiryMonitor expiry_monitor_;
 
   // Owned by AssistantService
-  chromeos::assistant::Assistant* assistant_ = nullptr;
+  assistant::Assistant* assistant_ = nullptr;
 
   const message_center::NotifierId notifier_id_;
 
diff --git a/ash/assistant/assistant_setup_controller.cc b/ash/assistant/assistant_setup_controller.cc
index 81b14b0..6085db9 100644
--- a/ash/assistant/assistant_setup_controller.cc
+++ b/ash/assistant/assistant_setup_controller.cc
@@ -51,7 +51,7 @@
 }
 
 void AssistantSetupController::OnOptInButtonPressed() {
-  using chromeos::assistant::prefs::ConsentStatus;
+  using assistant::prefs::ConsentStatus;
   if (AssistantState::Get()->consent_status().value_or(
           ConsentStatus::kUnknown) == ConsentStatus::kUnauthorized) {
     AssistantController::Get()->OpenUrl(assistant::util::CreateLocalizedGURL(
@@ -66,8 +66,7 @@
   if (!assistant_setup)
     return;
 
-  AssistantUiController::Get()->CloseUi(
-      chromeos::assistant::AssistantExitPoint::kSetup);
+  AssistantUiController::Get()->CloseUi(assistant::AssistantExitPoint::kSetup);
 
   assistant_setup->StartAssistantOptInFlow(
       type, base::BindOnce(&AssistantSetupController::OnOptInFlowFinished,
@@ -78,7 +77,7 @@
                                                    bool completed) {
   if (relaunch && completed) {
     AssistantUiController::Get()->ShowUi(
-        chromeos::assistant::AssistantEntryPoint::kSetup);
+        assistant::AssistantEntryPoint::kSetup);
   }
 }
 
diff --git a/ash/assistant/assistant_setup_controller_unittest.cc b/ash/assistant/assistant_setup_controller_unittest.cc
index 4af62f7..c0db5a03 100644
--- a/ash/assistant/assistant_setup_controller_unittest.cc
+++ b/ash/assistant/assistant_setup_controller_unittest.cc
@@ -28,7 +28,7 @@
   ShowAssistantUi(AssistantEntryPoint::kUnspecified);
   EXPECT_TRUE(IsVisible());
 
-  SetConsentStatus(chromeos::assistant::prefs::ConsentStatus::kUnknown);
+  SetConsentStatus(assistant::prefs::ConsentStatus::kUnknown);
   EXPECT_TRUE(opt_in_view()->GetVisible());
 
   ClickOnAndWait(opt_in_view());
@@ -43,7 +43,7 @@
   ShowAssistantUi(AssistantEntryPoint::kUnspecified);
   EXPECT_TRUE(IsVisible());
 
-  SetConsentStatus(chromeos::assistant::prefs::ConsentStatus::kUnknown);
+  SetConsentStatus(assistant::prefs::ConsentStatus::kUnknown);
   EXPECT_TRUE(opt_in_view()->GetVisible());
 
   ClickOnAndWait(opt_in_view());
@@ -56,7 +56,7 @@
   ShowAssistantUi(AssistantEntryPoint::kUnspecified);
   EXPECT_TRUE(IsVisible());
 
-  SetConsentStatus(chromeos::assistant::prefs::ConsentStatus::kUnknown);
+  SetConsentStatus(assistant::prefs::ConsentStatus::kUnknown);
   EXPECT_TRUE(opt_in_view()->GetVisible());
 
   ClickOnAndWait(opt_in_view());
@@ -73,7 +73,7 @@
   ShowAssistantUi(AssistantEntryPoint::kUnspecified);
   EXPECT_TRUE(IsVisible());
 
-  SetConsentStatus(chromeos::assistant::prefs::ConsentStatus::kUnknown);
+  SetConsentStatus(assistant::prefs::ConsentStatus::kUnknown);
   EXPECT_TRUE(opt_in_view()->GetVisible());
 
   ClickOnAndWait(opt_in_view());
diff --git a/ash/assistant/assistant_state_controller_unittest.cc b/ash/assistant/assistant_state_controller_unittest.cc
index 5d8744a3..74561fe4 100644
--- a/ash/assistant/assistant_state_controller_unittest.cc
+++ b/ash/assistant/assistant_state_controller_unittest.cc
@@ -18,18 +18,18 @@
 
 namespace {
 
-using chromeos::assistant::prefs::AssistantOnboardingMode;
-using chromeos::assistant::prefs::ConsentStatus;
-using chromeos::assistant::prefs::kAssistantConsentStatus;
-using chromeos::assistant::prefs::kAssistantContextEnabled;
-using chromeos::assistant::prefs::kAssistantEnabled;
-using chromeos::assistant::prefs::kAssistantHotwordAlwaysOn;
-using chromeos::assistant::prefs::kAssistantHotwordEnabled;
-using chromeos::assistant::prefs::kAssistantLaunchWithMicOpen;
-using chromeos::assistant::prefs::kAssistantNotificationEnabled;
-using chromeos::assistant::prefs::kAssistantOnboardingMode;
-using chromeos::assistant::prefs::kAssistantOnboardingModeDefault;
-using chromeos::assistant::prefs::kAssistantOnboardingModeEducation;
+using assistant::prefs::AssistantOnboardingMode;
+using assistant::prefs::ConsentStatus;
+using assistant::prefs::kAssistantConsentStatus;
+using assistant::prefs::kAssistantContextEnabled;
+using assistant::prefs::kAssistantEnabled;
+using assistant::prefs::kAssistantHotwordAlwaysOn;
+using assistant::prefs::kAssistantHotwordEnabled;
+using assistant::prefs::kAssistantLaunchWithMicOpen;
+using assistant::prefs::kAssistantNotificationEnabled;
+using assistant::prefs::kAssistantOnboardingMode;
+using assistant::prefs::kAssistantOnboardingModeDefault;
+using assistant::prefs::kAssistantOnboardingModeEducation;
 
 class TestAssistantStateObserver : public AssistantStateObserver {
  public:
diff --git a/ash/assistant/assistant_suggestions_controller_impl.cc b/ash/assistant/assistant_suggestions_controller_impl.cc
index a11c87e..7a6e0ff 100644
--- a/ash/assistant/assistant_suggestions_controller_impl.cc
+++ b/ash/assistant/assistant_suggestions_controller_impl.cc
@@ -29,9 +29,9 @@
 
 namespace {
 
+using assistant::prefs::AssistantOnboardingMode;
 using chromeos::assistant::AssistantSuggestion;
 using chromeos::assistant::AssistantSuggestionType;
-using chromeos::assistant::prefs::AssistantOnboardingMode;
 
 // Conversation starters -------------------------------------------------------
 
diff --git a/ash/assistant/assistant_suggestions_controller_impl.h b/ash/assistant/assistant_suggestions_controller_impl.h
index b54f9c0f..11e804f 100644
--- a/ash/assistant/assistant_suggestions_controller_impl.h
+++ b/ash/assistant/assistant_suggestions_controller_impl.h
@@ -49,8 +49,7 @@
   // AssistantStateObserver:
   void OnAssistantContextEnabled(bool enabled) override;
   void OnAssistantOnboardingModeChanged(
-      chromeos::assistant::prefs::AssistantOnboardingMode onboarding_mode)
-      override;
+      assistant::prefs::AssistantOnboardingMode onboarding_mode) override;
 
   void UpdateConversationStarters();
   void UpdateOnboardingSuggestions();
diff --git a/ash/assistant/assistant_suggestions_controller_impl_unittest.cc b/ash/assistant/assistant_suggestions_controller_impl_unittest.cc
index 41344c21..9bc0914 100644
--- a/ash/assistant/assistant_suggestions_controller_impl_unittest.cc
+++ b/ash/assistant/assistant_suggestions_controller_impl_unittest.cc
@@ -13,7 +13,7 @@
 
 namespace {
 
-using chromeos::assistant::prefs::AssistantOnboardingMode;
+using assistant::prefs::AssistantOnboardingMode;
 
 const AssistantSuggestionsModel* GetModel() {
   return AssistantSuggestionsController::Get()->GetModel();
diff --git a/ash/assistant/assistant_ui_controller_impl.cc b/ash/assistant/assistant_ui_controller_impl.cc
index ff3261c9..e99c7bc 100644
--- a/ash/assistant/assistant_ui_controller_impl.cc
+++ b/ash/assistant/assistant_ui_controller_impl.cc
@@ -81,8 +81,7 @@
       prefs::kAssistantNumSessionsWhereOnboardingShown, 0);
 }
 
-void AssistantUiControllerImpl::SetAssistant(
-    chromeos::assistant::Assistant* assistant) {
+void AssistantUiControllerImpl::SetAssistant(assistant::Assistant* assistant) {
   assistant_ = assistant;
 }
 
@@ -119,7 +118,7 @@
 
   // TODO(dmblack): Show a more helpful message to the user.
   if (assistant_state->assistant_status() ==
-      chromeos::assistant::AssistantStatus::NOT_READY) {
+      assistant::AssistantStatus::NOT_READY) {
     ShowUnboundErrorToast();
     return;
   }
@@ -144,7 +143,7 @@
   // provided the visibility change hasn't been invalidated.
   return base::ScopedClosureRunner(base::BindOnce(
       [](const base::WeakPtr<AssistantUiControllerImpl>& weak_ptr,
-         chromeos::assistant::AssistantExitPoint exit_point) {
+         assistant::AssistantExitPoint exit_point) {
         if (weak_ptr)
           weak_ptr->model_.SetClosed(exit_point);
       },
diff --git a/ash/assistant/assistant_ui_controller_impl.h b/ash/assistant/assistant_ui_controller_impl.h
index 517e65c7..674cee16 100644
--- a/ash/assistant/assistant_ui_controller_impl.h
+++ b/ash/assistant/assistant_ui_controller_impl.h
@@ -54,7 +54,7 @@
   static void RegisterProfilePrefs(PrefRegistrySimple* registry);
 
   // Provides a pointer to the |assistant| owned by AssistantService.
-  void SetAssistant(chromeos::assistant::Assistant* assistant);
+  void SetAssistant(assistant::Assistant* assistant);
 
   // AssistantUiController:
   const AssistantUiModel* GetModel() const override;
@@ -102,7 +102,7 @@
   bool has_shown_onboarding_ = false;
 
   // Owned by AssistantService.
-  chromeos::assistant::Assistant* assistant_ = nullptr;
+  assistant::Assistant* assistant_ = nullptr;
 
   base::ScopedObservation<AssistantController, AssistantControllerObserver>
       assistant_controller_observation_{this};
diff --git a/ash/assistant/assistant_view_delegate_impl.cc b/ash/assistant/assistant_view_delegate_impl.cc
index 0d7cf5dd..a551635 100644
--- a/ash/assistant/assistant_view_delegate_impl.cc
+++ b/ash/assistant/assistant_view_delegate_impl.cc
@@ -120,7 +120,7 @@
 bool AssistantViewDelegateImpl::ShouldShowOnboarding() const {
   // UI developers need to be able to force the onboarding flow.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          chromeos::assistant::switches::kForceAssistantOnboarding)) {
+          assistant::switches::kForceAssistantOnboarding)) {
     return true;
   }
 
diff --git a/ash/assistant/model/assistant_ui_model.h b/ash/assistant/model/assistant_ui_model.h
index 4483d64..78b28f2 100644
--- a/ash/assistant/model/assistant_ui_model.h
+++ b/ash/assistant/model/assistant_ui_model.h
@@ -45,8 +45,8 @@
 // Models the Assistant UI.
 class COMPONENT_EXPORT(ASSISTANT_MODEL) AssistantUiModel {
  public:
-  using AssistantEntryPoint = chromeos::assistant::AssistantEntryPoint;
-  using AssistantExitPoint = chromeos::assistant::AssistantExitPoint;
+  using AssistantEntryPoint = assistant::AssistantEntryPoint;
+  using AssistantExitPoint = assistant::AssistantExitPoint;
 
   AssistantUiModel();
 
diff --git a/ash/assistant/model/assistant_ui_model_observer.h b/ash/assistant/model/assistant_ui_model_observer.h
index 8131cb7..42a2f6a 100644
--- a/ash/assistant/model/assistant_ui_model_observer.h
+++ b/ash/assistant/model/assistant_ui_model_observer.h
@@ -10,14 +10,12 @@
 #include "third_party/abseil-cpp/absl/types/optional.h"
 #include "ui/gfx/geometry/rect.h"
 
-namespace chromeos {
+namespace ash {
+
 namespace assistant {
 enum class AssistantEntryPoint;
 enum class AssistantExitPoint;
 }  // namespace assistant
-}  // namespace chromeos
-
-namespace ash {
 
 enum class AssistantVisibility;
 
@@ -26,8 +24,8 @@
 class COMPONENT_EXPORT(ASSISTANT_MODEL) AssistantUiModelObserver
     : public base::CheckedObserver {
  public:
-  using AssistantEntryPoint = chromeos::assistant::AssistantEntryPoint;
-  using AssistantExitPoint = chromeos::assistant::AssistantExitPoint;
+  using AssistantEntryPoint = assistant::AssistantEntryPoint;
+  using AssistantExitPoint = assistant::AssistantExitPoint;
 
   AssistantUiModelObserver(const AssistantUiModelObserver&) = delete;
   AssistantUiModelObserver& operator=(const AssistantUiModelObserver&) = delete;
diff --git a/ash/assistant/test/assistant_ash_test_base.cc b/ash/assistant/test/assistant_ash_test_base.cc
index 04b9044..f2d3776 100644
--- a/ash/assistant/test/assistant_ash_test_base.cc
+++ b/ash/assistant/test/assistant_ash_test_base.cc
@@ -368,7 +368,7 @@
 
   // Set AssistantAllowedState to ALLOWED.
   test_api_->GetAssistantState()->NotifyFeatureAllowed(
-      chromeos::assistant::AssistantAllowedState::ALLOWED);
+      assistant::AssistantAllowedState::ALLOWED);
 
   // Set user consent so the suggestion chips are displayed.
   SetConsentStatus(ConsentStatus::kActivityControlAccepted);
@@ -376,7 +376,7 @@
   // At this point our Assistant service is ready for use.
   // Indicate this by changing status from NOT_READY to READY.
   test_api_->GetAssistantState()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+      assistant::AssistantStatus::READY);
 }
 
 }  // namespace ash
diff --git a/ash/assistant/test/assistant_ash_test_base.h b/ash/assistant/test/assistant_ash_test_base.h
index daee313e..a110bf2 100644
--- a/ash/assistant/test/assistant_ash_test_base.h
+++ b/ash/assistant/test/assistant_ash_test_base.h
@@ -43,11 +43,10 @@
 // Helper class to make testing the Assistant Ash UI easier.
 class AssistantAshTestBase : public AshTestBase {
  public:
-  using AssistantEntryPoint = chromeos::assistant::AssistantEntryPoint;
-  using AssistantExitPoint = chromeos::assistant::AssistantExitPoint;
-  using AssistantOnboardingMode =
-      chromeos::assistant::prefs::AssistantOnboardingMode;
-  using ConsentStatus = chromeos::assistant::prefs::ConsentStatus;
+  using AssistantEntryPoint = assistant::AssistantEntryPoint;
+  using AssistantExitPoint = assistant::AssistantExitPoint;
+  using AssistantOnboardingMode = assistant::prefs::AssistantOnboardingMode;
+  using ConsentStatus = assistant::prefs::ConsentStatus;
 
   AssistantAshTestBase();
   explicit AssistantAshTestBase(base::test::TaskEnvironment::TimeSource time);
diff --git a/ash/assistant/test/test_assistant_service.cc b/ash/assistant/test/test_assistant_service.cc
index cc5c97f..ab1ccdcb 100644
--- a/ash/assistant/test/test_assistant_service.cc
+++ b/ash/assistant/test/test_assistant_service.cc
@@ -17,9 +17,9 @@
 
 namespace ash {
 
+using assistant::AssistantInteractionResolution;
+using assistant::AssistantInteractionSubscriber;
 using chromeos::assistant::AssistantInteractionMetadata;
-using chromeos::assistant::AssistantInteractionResolution;
-using chromeos::assistant::AssistantInteractionSubscriber;
 using chromeos::assistant::AssistantInteractionType;
 using chromeos::assistant::AssistantSuggestion;
 
@@ -131,8 +131,7 @@
   Response() = default;
   virtual ~Response() = default;
 
-  virtual void SendTo(
-      chromeos::assistant::AssistantInteractionSubscriber* receiver) = 0;
+  virtual void SendTo(AssistantInteractionSubscriber* receiver) = 0;
 };
 
 class TextResponse : public InteractionResponse::Response {
@@ -144,8 +143,7 @@
 
   ~TextResponse() override = default;
 
-  void SendTo(
-      chromeos::assistant::AssistantInteractionSubscriber* receiver) override {
+  void SendTo(AssistantInteractionSubscriber* receiver) override {
     receiver->OnTextResponse(text_);
   }
 
@@ -160,8 +158,7 @@
   SuggestionsResponse& operator=(const SuggestionsResponse&) = delete;
   ~SuggestionsResponse() override = default;
 
-  void SendTo(
-      chromeos::assistant::AssistantInteractionSubscriber* receiver) override {
+  void SendTo(AssistantInteractionSubscriber* receiver) override {
     std::vector<AssistantSuggestion> suggestions;
     suggestions.emplace_back();
     auto& suggestion = suggestions.back();
@@ -186,8 +183,7 @@
 
   ~ResolutionResponse() override = default;
 
-  void SendTo(
-      chromeos::assistant::AssistantInteractionSubscriber* receiver) override {
+  void SendTo(AssistantInteractionSubscriber* receiver) override {
     receiver->OnInteractionFinished(resolution_);
   }
 
@@ -350,8 +346,7 @@
   responses_.push_back(std::move(response));
 }
 
-void InteractionResponse::SendTo(
-    chromeos::assistant::AssistantInteractionSubscriber* receiver) {
+void InteractionResponse::SendTo(AssistantInteractionSubscriber* receiver) {
   for (auto& response : responses_)
     response->SendTo(receiver);
 }
diff --git a/ash/assistant/test/test_assistant_service.h b/ash/assistant/test/test_assistant_service.h
index 3e220c8..f40a05b 100644
--- a/ash/assistant/test/test_assistant_service.h
+++ b/ash/assistant/test/test_assistant_service.h
@@ -34,7 +34,7 @@
 //     assistant_service()->SetInteractionResponse(std::move(response));
 class InteractionResponse {
  public:
-  using Resolution = chromeos::assistant::AssistantInteractionResolution;
+  using Resolution = assistant::AssistantInteractionResolution;
   class Response;
 
   InteractionResponse();
@@ -52,7 +52,7 @@
   // |resolution| to |AssistantInteractionSubscriber::OnInteractionFinished|.
   InteractionResponse* AddResolution(Resolution resolution);
 
-  void SendTo(chromeos::assistant::AssistantInteractionSubscriber* receiver);
+  void SendTo(assistant::AssistantInteractionSubscriber* receiver);
 
  private:
   void AddResponse(std::unique_ptr<Response> responses);
@@ -71,7 +71,7 @@
 //    - Finish a conversation before starting a new one.
 //    - Not send any responses (text, card, ...) before starting or after
 //      finishing an interaction.
-class TestAssistantService : public chromeos::assistant::Assistant {
+class TestAssistantService : public assistant::Assistant {
  public:
   TestAssistantService();
 
@@ -97,11 +97,11 @@
   void StartVoiceInteraction() override;
   void StopActiveInteraction(bool cancel_conversation) override;
   void AddAssistantInteractionSubscriber(
-      chromeos::assistant::AssistantInteractionSubscriber* subscriber) override;
+      assistant::AssistantInteractionSubscriber* subscriber) override;
   void RemoveAssistantInteractionSubscriber(
-      chromeos::assistant::AssistantInteractionSubscriber* subscriber) override;
+      assistant::AssistantInteractionSubscriber* subscriber) override;
   void AddRemoteConversationObserver(
-      chromeos::assistant::ConversationObserver* observer) override {}
+      assistant::ConversationObserver* observer) override {}
   mojo::PendingReceiver<chromeos::libassistant::mojom::NotificationDelegate>
   GetPendingNotificationDelegate() override;
   void RetrieveNotification(
@@ -137,7 +137,7 @@
 
   absl::optional<bool> dark_mode_enabled_;
 
-  base::ObserverList<chromeos::assistant::AssistantInteractionSubscriber>
+  base::ObserverList<assistant::AssistantInteractionSubscriber>
       interaction_subscribers_;
   bool running_active_interaction_ = false;
 
diff --git a/ash/assistant/ui/main_stage/assistant_footer_view.cc b/ash/assistant/ui/main_stage/assistant_footer_view.cc
index 51936a8..16377b8 100644
--- a/ash/assistant/ui/main_stage/assistant_footer_view.cc
+++ b/ash/assistant/ui/main_stage/assistant_footer_view.cc
@@ -74,8 +74,8 @@
   // Initial view state is based on user consent state.
   const bool consent_given =
       AssistantState::Get()->consent_status().value_or(
-          chromeos::assistant::prefs::ConsentStatus::kUnknown) ==
-      chromeos::assistant::prefs::ConsentStatus::kActivityControlAccepted;
+          assistant::prefs::ConsentStatus::kUnknown) ==
+      assistant::prefs::ConsentStatus::kActivityControlAccepted;
 
   // Suggestion container.
   suggestion_container_ =
@@ -106,7 +106,7 @@
 
   const bool consent_given =
       consent_status ==
-      chromeos::assistant::prefs::ConsentStatus::kActivityControlAccepted;
+      assistant::prefs::ConsentStatus::kActivityControlAccepted;
 
   // When the consent state changes, we need to hide/show the appropriate views.
   views::View* hide_view =
@@ -159,8 +159,8 @@
     const ui::CallbackLayerAnimationObserver& observer) {
   const bool consent_given =
       AssistantState::Get()->consent_status().value_or(
-          chromeos::assistant::prefs::ConsentStatus::kUnknown) ==
-      chromeos::assistant::prefs::ConsentStatus::kActivityControlAccepted;
+          assistant::prefs::ConsentStatus::kUnknown) ==
+      assistant::prefs::ConsentStatus::kActivityControlAccepted;
 
   // Only the view relevant to our consent state should process events.
   suggestion_container_->SetCanProcessEventsWithinSubtree(consent_given);
diff --git a/ash/assistant/ui/main_stage/assistant_onboarding_view_unittest.cc b/ash/assistant/ui/main_stage/assistant_onboarding_view_unittest.cc
index d7ec3b1..9a51f12 100644
--- a/ash/assistant/ui/main_stage/assistant_onboarding_view_unittest.cc
+++ b/ash/assistant/ui/main_stage/assistant_onboarding_view_unittest.cc
@@ -83,8 +83,7 @@
 // Mocks -----------------------------------------------------------------------
 
 class MockAssistantInteractionSubscriber
-    : public testing::NiceMock<
-          chromeos::assistant::AssistantInteractionSubscriber> {
+    : public testing::NiceMock<assistant::AssistantInteractionSubscriber> {
  public:
   explicit MockAssistantInteractionSubscriber(Assistant* service) {
     scoped_subscriber_.Observe(service);
@@ -98,8 +97,7 @@
               (override));
 
  private:
-  chromeos::assistant::ScopedAssistantInteractionSubscriber scoped_subscriber_{
-      this};
+  assistant::ScopedAssistantInteractionSubscriber scoped_subscriber_{this};
 };
 
 // ScopedShowUi ----------------------------------------------------------------
@@ -110,7 +108,7 @@
       : original_visibility_(
             AssistantUiController::Get()->GetModel()->visibility()) {
     AssistantUiController::Get()->ShowUi(
-        chromeos::assistant::AssistantEntryPoint::kUnspecified);
+        assistant::AssistantEntryPoint::kUnspecified);
   }
 
   ScopedShowUi(const ScopedShowUi&) = delete;
@@ -120,7 +118,7 @@
     switch (original_visibility_) {
       case AssistantVisibility::kClosed:
         AssistantUiController::Get()->CloseUi(
-            chromeos::assistant::AssistantExitPoint::kUnspecified);
+            assistant::AssistantExitPoint::kUnspecified);
         return;
       case AssistantVisibility::kVisible:
         // No action necessary.
diff --git a/ash/assistant/ui/main_stage/assistant_opt_in_view.cc b/ash/assistant/ui/main_stage/assistant_opt_in_view.cc
index 35f97dd..af36b80 100644
--- a/ash/assistant/ui/main_stage/assistant_opt_in_view.cc
+++ b/ash/assistant/ui/main_stage/assistant_opt_in_view.cc
@@ -40,8 +40,7 @@
 }
 
 std::u16string GetAction(int consent_status) {
-  return consent_status ==
-                 chromeos::assistant::prefs::ConsentStatus::kUnauthorized
+  return consent_status == assistant::prefs::ConsentStatus::kUnauthorized
              ? l10n_util::GetStringUTF16(
                    IDS_ASH_ASSISTANT_OPT_IN_ASK_ADMINISTRATOR)
              : l10n_util::GetStringUTF16(IDS_ASH_ASSISTANT_OPT_IN_GET_STARTED);
@@ -146,7 +145,7 @@
   label_->SetHorizontalAlignment(gfx::HorizontalAlignment::ALIGN_CENTER);
 
   UpdateLabel(AssistantState::Get()->consent_status().value_or(
-      chromeos::assistant::prefs::ConsentStatus::kUnknown));
+      assistant::prefs::ConsentStatus::kUnknown));
 }
 
 void AssistantOptInView::UpdateLabel(int consent_status) {
diff --git a/ash/assistant/util/assistant_util.cc b/ash/assistant/util/assistant_util.cc
index a4ee8301..3f7c5ec6 100644
--- a/ash/assistant/util/assistant_util.cc
+++ b/ash/assistant/util/assistant_util.cc
@@ -20,8 +20,6 @@
 namespace assistant {
 namespace util {
 
-using chromeos::assistant::AssistantEntryPoint;
-
 bool IsStartingSession(AssistantVisibility new_visibility,
                        AssistantVisibility old_visibility) {
   return old_visibility == AssistantVisibility::kClosed &&
diff --git a/ash/assistant/util/assistant_util.h b/ash/assistant/util/assistant_util.h
index e29b09f..96ac324 100644
--- a/ash/assistant/util/assistant_util.h
+++ b/ash/assistant/util/assistant_util.h
@@ -7,13 +7,11 @@
 
 #include "base/component_export.h"
 
-namespace chromeos {
+namespace ash {
+
 namespace assistant {
 enum class AssistantEntryPoint;
-}  // namespace assistant
-}  // namespace chromeos
-
-namespace ash {
+}
 
 enum class AssistantVisibility;
 
@@ -34,8 +32,7 @@
 // |prefer_voice| is true if user prefers voice input modality or if the device
 // is in tablet mode.
 COMPONENT_EXPORT(ASSISTANT_UTIL)
-bool IsVoiceEntryPoint(chromeos::assistant::AssistantEntryPoint entry_point,
-                       bool prefer_voice);
+bool IsVoiceEntryPoint(AssistantEntryPoint entry_point, bool prefer_voice);
 
 COMPONENT_EXPORT(ASSISTANT_UTIL)
 bool IsGoogleDevice();
diff --git a/ash/assistant/util/deep_link_util.cc b/ash/assistant/util/deep_link_util.cc
index aa6ce57..f7339f8 100644
--- a/ash/assistant/util/deep_link_util.cc
+++ b/ash/assistant/util/deep_link_util.cc
@@ -22,7 +22,6 @@
 
 namespace {
 
-using chromeos::assistant::AssistantEntryPoint;
 using chromeos::assistant::AssistantQuerySource;
 
 // Supported deep link param keys. These values must be kept in sync with the
diff --git a/ash/assistant/util/deep_link_util.h b/ash/assistant/util/deep_link_util.h
index 6aeb7d2..c5dbe1c 100644
--- a/ash/assistant/util/deep_link_util.h
+++ b/ash/assistant/util/deep_link_util.h
@@ -14,15 +14,15 @@
 
 class GURL;
 
-namespace chromeos {
-namespace assistant {
-enum class AssistantEntryPoint;
+namespace chromeos::assistant {
 enum class AssistantQuerySource;
-}  // namespace assistant
-}  // namespace chromeos
+}
 
 namespace ash {
 namespace assistant {
+
+enum class AssistantEntryPoint;
+
 namespace util {
 
 // Enumeration of deep link types.
@@ -79,9 +79,8 @@
 // Returns a new deep link, having appended or replaced the entry point param
 // from the original |deep_link| with |entry_point|.
 COMPONENT_EXPORT(ASSISTANT_UTIL)
-GURL AppendOrReplaceEntryPointParam(
-    const GURL& deep_link,
-    chromeos::assistant::AssistantEntryPoint entry_point);
+GURL AppendOrReplaceEntryPointParam(const GURL& deep_link,
+                                    AssistantEntryPoint entry_point);
 
 // Returns a new deep link, having appended or replaced the query source param
 // from the original |deep_link| with |query_source|.
@@ -135,9 +134,9 @@
 // desired parameter is not found or is not mappable to an Assistant entry
 // point, an empty value is returned.
 COMPONENT_EXPORT(ASSISTANT_UTIL)
-absl::optional<chromeos::assistant::AssistantEntryPoint>
-GetDeepLinkParamAsEntryPoint(const std::map<std::string, std::string>& params,
-                             DeepLinkParam param);
+absl::optional<AssistantEntryPoint> GetDeepLinkParamAsEntryPoint(
+    const std::map<std::string, std::string>& params,
+    DeepLinkParam param);
 
 // Returns a specific GURL |param| from the given parameters. If the desired
 // parameter is not found, an absent value is returned.
diff --git a/ash/assistant/util/deep_link_util_unittest.cc b/ash/assistant/util/deep_link_util_unittest.cc
index 8e9c568..581ebf1 100644
--- a/ash/assistant/util/deep_link_util_unittest.cc
+++ b/ash/assistant/util/deep_link_util_unittest.cc
@@ -20,7 +20,6 @@
 namespace assistant {
 namespace util {
 
-using chromeos::assistant::AssistantEntryPoint;
 using chromeos::assistant::AssistantQuerySource;
 
 using DeepLinkUtilTest = AshTestBase;
diff --git a/ash/assistant/util/histogram_util.cc b/ash/assistant/util/histogram_util.cc
index a5ec4c69..011606a2 100644
--- a/ash/assistant/util/histogram_util.cc
+++ b/ash/assistant/util/histogram_util.cc
@@ -13,17 +13,15 @@
 namespace util {
 
 void IncrementAssistantQueryCountForEntryPoint(
-    chromeos::assistant::AssistantEntryPoint entry_point) {
+    AssistantEntryPoint entry_point) {
   UMA_HISTOGRAM_ENUMERATION("Assistant.QueryCountPerEntryPoint", entry_point);
 }
 
-void RecordAssistantEntryPoint(
-    chromeos::assistant::AssistantEntryPoint entry_point) {
+void RecordAssistantEntryPoint(AssistantEntryPoint entry_point) {
   UMA_HISTOGRAM_ENUMERATION("Assistant.EntryPoint", entry_point);
 }
 
-void RecordAssistantExitPoint(
-    chromeos::assistant::AssistantExitPoint exit_point) {
+void RecordAssistantExitPoint(AssistantExitPoint exit_point) {
   UMA_HISTOGRAM_ENUMERATION("Assistant.ExitPoint", exit_point);
 }
 
diff --git a/ash/assistant/util/histogram_util.h b/ash/assistant/util/histogram_util.h
index d7e9a634..44334135 100644
--- a/ash/assistant/util/histogram_util.h
+++ b/ash/assistant/util/histogram_util.h
@@ -17,18 +17,15 @@
 
 // Increment number of queries fired for each entry point.
 COMPONENT_EXPORT(ASSISTANT_UTIL)
-void IncrementAssistantQueryCountForEntryPoint(
-    chromeos::assistant::AssistantEntryPoint entry_point);
+void IncrementAssistantQueryCountForEntryPoint(AssistantEntryPoint entry_point);
 
 // Record the entry point where Assistant UI becomes visible.
 COMPONENT_EXPORT(ASSISTANT_UTIL)
-void RecordAssistantEntryPoint(
-    chromeos::assistant::AssistantEntryPoint entry_point);
+void RecordAssistantEntryPoint(AssistantEntryPoint entry_point);
 
 // Record the exit point where Assistant UI becomes invisible.
 COMPONENT_EXPORT(ASSISTANT_UTIL)
-void RecordAssistantExitPoint(
-    chromeos::assistant::AssistantExitPoint exit_point);
+void RecordAssistantExitPoint(AssistantExitPoint exit_point);
 
 // Count the number of times buttons are clicked on Assistant UI.
 COMPONENT_EXPORT(ASSISTANT_UTIL)
diff --git a/ash/clipboard/clipboard_nudge.cc b/ash/clipboard/clipboard_nudge.cc
index 037acff..1908b7ac 100644
--- a/ash/clipboard/clipboard_nudge.cc
+++ b/ash/clipboard/clipboard_nudge.cc
@@ -51,8 +51,7 @@
 
 bool IsAssistantAvailable() {
   AssistantStateBase* state = AssistantState::Get();
-  return state->allowed_state() ==
-             chromeos::assistant::AssistantAllowedState::ALLOWED &&
+  return state->allowed_state() == assistant::AssistantAllowedState::ALLOWED &&
          state->settings_enabled().value_or(false);
 }
 
diff --git a/ash/public/cpp/assistant/assistant_state.cc b/ash/public/cpp/assistant/assistant_state.cc
index 468e50e..3d328f8 100644
--- a/ash/public/cpp/assistant/assistant_state.cc
+++ b/ash/public/cpp/assistant/assistant_state.cc
@@ -35,8 +35,7 @@
   g_assistant_state = nullptr;
 }
 
-void AssistantState::NotifyStatusChanged(
-    chromeos::assistant::AssistantStatus status) {
+void AssistantState::NotifyStatusChanged(assistant::AssistantStatus status) {
   if (assistant_status_ == status)
     return;
 
@@ -44,7 +43,7 @@
 }
 
 void AssistantState::NotifyFeatureAllowed(
-    chromeos::assistant::AssistantAllowedState state) {
+    assistant::AssistantAllowedState state) {
   if (allowed_state_ == state)
     return;
 
diff --git a/ash/public/cpp/assistant/assistant_state.h b/ash/public/cpp/assistant/assistant_state.h
index e6cd429..3d8ede5 100644
--- a/ash/public/cpp/assistant/assistant_state.h
+++ b/ash/public/cpp/assistant/assistant_state.h
@@ -28,8 +28,8 @@
 
   ~AssistantState() override;
 
-  void NotifyStatusChanged(chromeos::assistant::AssistantStatus status);
-  void NotifyFeatureAllowed(chromeos::assistant::AssistantAllowedState state);
+  void NotifyStatusChanged(assistant::AssistantStatus status);
+  void NotifyFeatureAllowed(assistant::AssistantAllowedState state);
   void NotifyLocaleChanged(const std::string& locale);
   void NotifyArcPlayStoreEnabledChanged(bool enabled);
   void NotifyLockedFullScreenStateChanged(bool enabled);
diff --git a/ash/public/cpp/assistant/assistant_state_base.cc b/ash/public/cpp/assistant/assistant_state_base.cc
index b9ac426d..f9c0c37 100644
--- a/ash/public/cpp/assistant/assistant_state_base.cc
+++ b/ash/public/cpp/assistant/assistant_state_base.cc
@@ -19,7 +19,7 @@
 
 namespace {
 
-using chromeos::assistant::prefs::AssistantOnboardingMode;
+using assistant::prefs::AssistantOnboardingMode;
 
 #define PRINT_VALUE(value) PrintValue(&result, #value, value())
 
@@ -87,35 +87,35 @@
   pref_change_registrar_ = std::make_unique<PrefChangeRegistrar>();
   pref_change_registrar_->Init(pref_service);
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantConsentStatus,
+      assistant::prefs::kAssistantConsentStatus,
       base::BindRepeating(&AssistantStateBase::UpdateConsentStatus,
                           base::Unretained(this)));
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantContextEnabled,
+      assistant::prefs::kAssistantContextEnabled,
       base::BindRepeating(&AssistantStateBase::UpdateContextEnabled,
                           base::Unretained(this)));
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantEnabled,
+      assistant::prefs::kAssistantEnabled,
       base::BindRepeating(&AssistantStateBase::UpdateSettingsEnabled,
                           base::Unretained(this)));
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantHotwordAlwaysOn,
+      assistant::prefs::kAssistantHotwordAlwaysOn,
       base::BindRepeating(&AssistantStateBase::UpdateHotwordAlwaysOn,
                           base::Unretained(this)));
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantHotwordEnabled,
+      assistant::prefs::kAssistantHotwordEnabled,
       base::BindRepeating(&AssistantStateBase::UpdateHotwordEnabled,
                           base::Unretained(this)));
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantLaunchWithMicOpen,
+      assistant::prefs::kAssistantLaunchWithMicOpen,
       base::BindRepeating(&AssistantStateBase::UpdateLaunchWithMicOpen,
                           base::Unretained(this)));
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantNotificationEnabled,
+      assistant::prefs::kAssistantNotificationEnabled,
       base::BindRepeating(&AssistantStateBase::UpdateNotificationEnabled,
                           base::Unretained(this)));
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantOnboardingMode,
+      assistant::prefs::kAssistantOnboardingMode,
       base::BindRepeating(&AssistantStateBase::UpdateOnboardingMode,
                           base::Unretained(this)));
 
@@ -130,8 +130,7 @@
 }
 
 bool AssistantStateBase::IsScreenContextAllowed() const {
-  return allowed_state() ==
-             chromeos::assistant::AssistantAllowedState::ALLOWED &&
+  return allowed_state() == assistant::AssistantAllowedState::ALLOWED &&
          settings_enabled().value_or(false) &&
          context_enabled().value_or(false);
 }
@@ -175,7 +174,7 @@
 
 void AssistantStateBase::UpdateConsentStatus() {
   auto consent_status = pref_change_registrar_->prefs()->GetInteger(
-      chromeos::assistant::prefs::kAssistantConsentStatus);
+      assistant::prefs::kAssistantConsentStatus);
   if (consent_status_.has_value() &&
       consent_status_.value() == consent_status) {
     return;
@@ -187,7 +186,7 @@
 
 void AssistantStateBase::UpdateContextEnabled() {
   auto context_enabled = pref_change_registrar_->prefs()->GetBoolean(
-      chromeos::assistant::prefs::kAssistantContextEnabled);
+      assistant::prefs::kAssistantContextEnabled);
   if (context_enabled_.has_value() &&
       context_enabled_.value() == context_enabled) {
     return;
@@ -199,7 +198,7 @@
 
 void AssistantStateBase::UpdateSettingsEnabled() {
   auto settings_enabled = pref_change_registrar_->prefs()->GetBoolean(
-      chromeos::assistant::prefs::kAssistantEnabled);
+      assistant::prefs::kAssistantEnabled);
   if (settings_enabled_.has_value() &&
       settings_enabled_.value() == settings_enabled) {
     return;
@@ -211,7 +210,7 @@
 
 void AssistantStateBase::UpdateHotwordAlwaysOn() {
   auto hotword_always_on = pref_change_registrar_->prefs()->GetBoolean(
-      chromeos::assistant::prefs::kAssistantHotwordAlwaysOn);
+      assistant::prefs::kAssistantHotwordAlwaysOn);
   if (hotword_always_on_.has_value() &&
       hotword_always_on_.value() == hotword_always_on) {
     return;
@@ -223,7 +222,7 @@
 
 void AssistantStateBase::UpdateHotwordEnabled() {
   auto hotword_enabled = pref_change_registrar_->prefs()->GetBoolean(
-      chromeos::assistant::prefs::kAssistantHotwordEnabled);
+      assistant::prefs::kAssistantHotwordEnabled);
   if (hotword_enabled_.has_value() &&
       hotword_enabled_.value() == hotword_enabled) {
     return;
@@ -235,7 +234,7 @@
 
 void AssistantStateBase::UpdateLaunchWithMicOpen() {
   auto launch_with_mic_open = pref_change_registrar_->prefs()->GetBoolean(
-      chromeos::assistant::prefs::kAssistantLaunchWithMicOpen);
+      assistant::prefs::kAssistantLaunchWithMicOpen);
   if (launch_with_mic_open_.has_value() &&
       launch_with_mic_open_.value() == launch_with_mic_open) {
     return;
@@ -247,7 +246,7 @@
 
 void AssistantStateBase::UpdateNotificationEnabled() {
   auto notification_enabled = pref_change_registrar_->prefs()->GetBoolean(
-      chromeos::assistant::prefs::kAssistantNotificationEnabled);
+      assistant::prefs::kAssistantNotificationEnabled);
   if (notification_enabled_.has_value() &&
       notification_enabled_.value() == notification_enabled) {
     return;
@@ -258,10 +257,9 @@
 }
 
 void AssistantStateBase::UpdateOnboardingMode() {
-  AssistantOnboardingMode onboarding_mode =
-      chromeos::assistant::prefs::ToOnboardingMode(
-          pref_change_registrar_->prefs()->GetString(
-              chromeos::assistant::prefs::kAssistantOnboardingMode));
+  AssistantOnboardingMode onboarding_mode = assistant::prefs::ToOnboardingMode(
+      pref_change_registrar_->prefs()->GetString(
+          assistant::prefs::kAssistantOnboardingMode));
 
   if (onboarding_mode_ == onboarding_mode)
     return;
@@ -272,14 +270,14 @@
 }
 
 void AssistantStateBase::UpdateAssistantStatus(
-    chromeos::assistant::AssistantStatus status) {
+    assistant::AssistantStatus status) {
   assistant_status_ = status;
   for (auto& observer : observers_)
     observer.OnAssistantStatusChanged(assistant_status_);
 }
 
 void AssistantStateBase::UpdateFeatureAllowedState(
-    chromeos::assistant::AssistantAllowedState state) {
+    assistant::AssistantAllowedState state) {
   allowed_state_ = state;
   for (auto& observer : observers_)
     observer.OnAssistantFeatureAllowedChanged(allowed_state_.value());
diff --git a/ash/public/cpp/assistant/assistant_state_base.h b/ash/public/cpp/assistant/assistant_state_base.h
index fa60383..8e26638 100644
--- a/ash/public/cpp/assistant/assistant_state_base.h
+++ b/ash/public/cpp/assistant/assistant_state_base.h
@@ -38,12 +38,11 @@
   virtual void OnAssistantLaunchWithMicOpen(bool launch_with_mic_open) {}
   virtual void OnAssistantNotificationEnabled(bool notification_enabled) {}
   virtual void OnAssistantOnboardingModeChanged(
-      chromeos::assistant::prefs::AssistantOnboardingMode onboarding_mode) {}
+      assistant::prefs::AssistantOnboardingMode onboarding_mode) {}
   virtual void OnAssistantStateDestroyed() {}
-  virtual void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus status) {}
+  virtual void OnAssistantStatusChanged(assistant::AssistantStatus status) {}
   virtual void OnAssistantFeatureAllowedChanged(
-      chromeos::assistant::AssistantAllowedState state) {}
+      assistant::AssistantAllowedState state) {}
   virtual void OnArcPlayStoreEnabledChanged(bool enabled) {}
   virtual void OnLocaleChanged(const std::string& locale) {}
   virtual void OnLockedFullScreenStateChanged(bool enabled) {}
@@ -63,7 +62,7 @@
 
   virtual ~AssistantStateBase();
 
-  chromeos::assistant::AssistantStatus assistant_status() const {
+  assistant::AssistantStatus assistant_status() const {
     return assistant_status_;
   }
 
@@ -93,13 +92,13 @@
     return notification_enabled_;
   }
 
-  const absl::optional<chromeos::assistant::prefs::AssistantOnboardingMode>&
+  const absl::optional<assistant::prefs::AssistantOnboardingMode>&
   onboarding_mode() const {
     return onboarding_mode_;
   }
 
-  const absl::optional<chromeos::assistant::AssistantAllowedState>&
-  allowed_state() const {
+  const absl::optional<assistant::AssistantAllowedState>& allowed_state()
+      const {
     return allowed_state_;
   }
 
@@ -138,15 +137,14 @@
   void UpdateOnboardingMode();
 
   // Called when new values of the listened states are received.
-  void UpdateAssistantStatus(chromeos::assistant::AssistantStatus status);
-  void UpdateFeatureAllowedState(
-      chromeos::assistant::AssistantAllowedState state);
+  void UpdateAssistantStatus(assistant::AssistantStatus status);
+  void UpdateFeatureAllowedState(assistant::AssistantAllowedState state);
   void UpdateLocale(const std::string& locale);
   void UpdateArcPlayStoreEnabled(bool enabled);
   void UpdateLockedFullScreenState(bool enabled);
 
-  chromeos::assistant::AssistantStatus assistant_status_ =
-      chromeos::assistant::AssistantStatus::NOT_READY;
+  assistant::AssistantStatus assistant_status_ =
+      assistant::AssistantStatus::NOT_READY;
 
   // TODO(b/138679823): Maybe remove Optional for preference values.
   // Whether the Assistant is enabled in system settings. nullopt if the
@@ -174,12 +172,11 @@
   absl::optional<bool> notification_enabled_;
 
   // The mode for the Assistant onboarding experience.
-  absl::optional<chromeos::assistant::prefs::AssistantOnboardingMode>
-      onboarding_mode_;
+  absl::optional<assistant::prefs::AssistantOnboardingMode> onboarding_mode_;
 
   // Whether the Assistant feature is allowed or disallowed for what reason.
   // nullopt if the data is not available yet.
-  absl::optional<chromeos::assistant::AssistantAllowedState> allowed_state_;
+  absl::optional<assistant::AssistantAllowedState> allowed_state_;
 
   absl::optional<std::string> locale_;
 
diff --git a/ash/public/cpp/assistant/controller/assistant_controller.h b/ash/public/cpp/assistant/controller/assistant_controller.h
index 9c611a76..a396bcb 100644
--- a/ash/public/cpp/assistant/controller/assistant_controller.h
+++ b/ash/public/cpp/assistant/controller/assistant_controller.h
@@ -40,7 +40,7 @@
   virtual base::WeakPtr<AssistantController> GetWeakPtr() = 0;
 
   // Provides a reference to the underlying |assistant| service.
-  virtual void SetAssistant(chromeos::assistant::Assistant* assistant) = 0;
+  virtual void SetAssistant(assistant::Assistant* assistant) = 0;
 
   // Methods below may only be called after |SetAssistant| is called.
   // Show speaker id enrollment flow.
diff --git a/ash/public/cpp/assistant/controller/assistant_ui_controller.h b/ash/public/cpp/assistant/controller/assistant_ui_controller.h
index 1100a5a..c62a622 100644
--- a/ash/public/cpp/assistant/controller/assistant_ui_controller.h
+++ b/ash/public/cpp/assistant/controller/assistant_ui_controller.h
@@ -9,14 +9,12 @@
 #include "base/callback_helpers.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
 
-namespace chromeos {
+namespace ash {
+
 namespace assistant {
 enum class AssistantEntryPoint;
 enum class AssistantExitPoint;
 }  // namespace assistant
-}  // namespace chromeos
-
-namespace ash {
 
 class AssistantUiModel;
 
@@ -40,16 +38,15 @@
   virtual void SetKeyboardTraversalMode(bool) = 0;
 
   // Invoke to show/toggle Assistant UI.
-  virtual void ShowUi(chromeos::assistant::AssistantEntryPoint) = 0;
-  virtual void ToggleUi(
-      absl::optional<chromeos::assistant::AssistantEntryPoint>,
-      absl::optional<chromeos::assistant::AssistantExitPoint>) = 0;
+  virtual void ShowUi(assistant::AssistantEntryPoint) = 0;
+  virtual void ToggleUi(absl::optional<assistant::AssistantEntryPoint>,
+                        absl::optional<assistant::AssistantExitPoint>) = 0;
 
   // Returns a closure to close Assistant UI. If the return value is ignored,
   // the Assistant UI is closed instantly; otherwise, the UI is in closing
   // state until the closure is run.
   virtual absl::optional<base::ScopedClosureRunner> CloseUi(
-      chromeos::assistant::AssistantExitPoint) = 0;
+      assistant::AssistantExitPoint) = 0;
 
   // Sets current AppListBubbleWidth. AssistantCardElement needs to know the
   // width of AppListBubbleWidth to render its html content.
diff --git a/ash/public/cpp/assistant/test_support/mock_assistant_state.cc b/ash/public/cpp/assistant/test_support/mock_assistant_state.cc
index 682dabb..42044e9 100644
--- a/ash/public/cpp/assistant/test_support/mock_assistant_state.cc
+++ b/ash/public/cpp/assistant/test_support/mock_assistant_state.cc
@@ -7,14 +7,14 @@
 namespace ash {
 
 MockAssistantState::MockAssistantState() {
-  allowed_state_ = chromeos::assistant::AssistantAllowedState::ALLOWED;
+  allowed_state_ = assistant::AssistantAllowedState::ALLOWED;
   settings_enabled_ = true;
 }
 
 MockAssistantState::~MockAssistantState() = default;
 
 void MockAssistantState::SetAllowedState(
-    chromeos::assistant::AssistantAllowedState allowed_state) {
+    assistant::AssistantAllowedState allowed_state) {
   if (allowed_state_ != allowed_state) {
     allowed_state_ = allowed_state;
     for (auto& observer : observers_)
diff --git a/ash/public/cpp/assistant/test_support/mock_assistant_state.h b/ash/public/cpp/assistant/test_support/mock_assistant_state.h
index 1bd1477..22585770 100644
--- a/ash/public/cpp/assistant/test_support/mock_assistant_state.h
+++ b/ash/public/cpp/assistant/test_support/mock_assistant_state.h
@@ -16,8 +16,7 @@
   MockAssistantState& operator=(const MockAssistantState&) = delete;
   ~MockAssistantState() override;
 
-  void SetAllowedState(
-      chromeos::assistant::AssistantAllowedState allowed_state);
+  void SetAllowedState(assistant::AssistantAllowedState allowed_state);
 
   void SetSettingsEnabled(bool enabled);
 };
diff --git a/ash/public/cpp/test/assistant_test_api.h b/ash/public/cpp/test/assistant_test_api.h
index 9c2cccd..2feaedf 100644
--- a/ash/public/cpp/test/assistant_test_api.h
+++ b/ash/public/cpp/test/assistant_test_api.h
@@ -63,7 +63,7 @@
   virtual void SetTabletMode(bool enable) = 0;
 
   // Changes the user preference controlling the status of user consent.
-  virtual void SetConsentStatus(chromeos::assistant::prefs::ConsentStatus) = 0;
+  virtual void SetConsentStatus(assistant::prefs::ConsentStatus) = 0;
 
   // Sets the number of user sessions where Assistant onboarding was shown.
   virtual void SetNumberOfSessionsWhereOnboardingShown(
@@ -71,7 +71,7 @@
 
   // Changes the user preference controlling the mode of the onboarding UX.
   virtual void SetOnboardingMode(
-      chromeos::assistant::prefs::AssistantOnboardingMode onboarding_mode) = 0;
+      assistant::prefs::AssistantOnboardingMode onboarding_mode) = 0;
 
   // Changes the user setting controlling whether the user prefers voice or
   // keyboard (internally called |kAssistantLaunchWithMicOpen|).
diff --git a/ash/shelf/assistant_overlay_unittest.cc b/ash/shelf/assistant_overlay_unittest.cc
index cf05234..987ce11d 100644
--- a/ash/shelf/assistant_overlay_unittest.cc
+++ b/ash/shelf/assistant_overlay_unittest.cc
@@ -65,12 +65,11 @@
 
     // Enable Assistant
     Shell::Get()->session_controller()->GetPrimaryUserPrefService()->SetBoolean(
-        chromeos::assistant::prefs::kAssistantEnabled, true);
+        assistant::prefs::kAssistantEnabled, true);
     AssistantState* assistant_state = AssistantState::Get();
     assistant_state->NotifyFeatureAllowed(
-        chromeos::assistant::AssistantAllowedState::ALLOWED);
-    assistant_state->NotifyStatusChanged(
-        chromeos::assistant::AssistantStatus::READY);
+        assistant::AssistantAllowedState::ALLOWED);
+    assistant_state->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
     const TestVariant test_variant = GetParam();
     switch (test_variant) {
diff --git a/ash/shelf/home_button_controller.cc b/ash/shelf/home_button_controller.cc
index 17294c2..b9271a6 100644
--- a/ash/shelf/home_button_controller.cc
+++ b/ash/shelf/home_button_controller.cc
@@ -130,8 +130,7 @@
 
 bool HomeButtonController::IsAssistantAvailable() {
   AssistantStateBase* state = AssistantState::Get();
-  return state->allowed_state() ==
-             chromeos::assistant::AssistantAllowedState::ALLOWED &&
+  return state->allowed_state() == assistant::AssistantAllowedState::ALLOWED &&
          state->settings_enabled().value_or(false);
 }
 
@@ -156,7 +155,7 @@
 }
 
 void HomeButtonController::OnAssistantFeatureAllowedChanged(
-    chromeos::assistant::AssistantAllowedState state) {
+    assistant::AssistantAllowedState state) {
   button_->OnAssistantAvailabilityChanged();
 }
 
diff --git a/ash/shelf/home_button_controller.h b/ash/shelf/home_button_controller.h
index 6db20207..025f354 100644
--- a/ash/shelf/home_button_controller.h
+++ b/ash/shelf/home_button_controller.h
@@ -56,7 +56,7 @@
 
   // AssistantStateObserver:
   void OnAssistantFeatureAllowedChanged(
-      chromeos::assistant::AssistantAllowedState) override;
+      assistant::AssistantAllowedState) override;
   void OnAssistantSettingsEnabled(bool enabled) override;
 
   // AssistantUiModelObserver:
diff --git a/ash/shelf/home_button_unittest.cc b/ash/shelf/home_button_unittest.cc
index f8d615db..7c45e0f 100644
--- a/ash/shelf/home_button_unittest.cc
+++ b/ash/shelf/home_button_unittest.cc
@@ -596,11 +596,10 @@
   CreateUserSessions(2);
 
   // Enable the Assistant in system settings.
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
   assistant_state()->NotifyFeatureAllowed(
-      chromeos::assistant::AssistantAllowedState::ALLOWED);
-  assistant_state()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+      assistant::AssistantAllowedState::ALLOWED);
+  assistant_state()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   ShelfNavigationWidget::TestApi test_api(
       GetPrimaryShelf()->navigation_widget());
@@ -615,7 +614,7 @@
             AssistantUiController::Get()->GetModel()->visibility());
 
   AssistantUiController::Get()->CloseUi(
-      chromeos::assistant::AssistantExitPoint::kUnspecified);
+      assistant::AssistantExitPoint::kUnspecified);
   // Test long press gesture on secondary display.
   SendGestureEventToSecondaryDisplay(&long_press);
   GetAppListTestHelper()->WaitUntilIdle();
@@ -628,11 +627,10 @@
   CreateUserSessions(2);
 
   // Enable the Assistant in system settings.
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
   assistant_state()->NotifyFeatureAllowed(
-      chromeos::assistant::AssistantAllowedState::ALLOWED);
-  assistant_state()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+      assistant::AssistantAllowedState::ALLOWED);
+  assistant_state()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   Shell::Get()->tablet_mode_controller()->SetEnabledForTest(true);
 
@@ -671,17 +669,16 @@
             AssistantUiController::Get()->GetModel()->visibility());
 
   AssistantUiController::Get()->CloseUi(
-      chromeos::assistant::AssistantExitPoint::kUnspecified);
+      assistant::AssistantExitPoint::kUnspecified);
 }
 
 TEST_P(HomeButtonTest, LongPressGestureWithSecondaryUser) {
   // Disallowed by secondary user.
   assistant_state()->NotifyFeatureAllowed(
-      chromeos::assistant::AssistantAllowedState::
-          DISALLOWED_BY_NONPRIMARY_USER);
+      assistant::AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER);
 
   // Enable the Assistant in system settings.
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
 
   ShelfNavigationWidget::TestApi test_api(
       GetPrimaryShelf()->navigation_widget());
@@ -707,9 +704,9 @@
 
   // Simulate a user who has already completed setup flow, but disabled the
   // Assistant in settings.
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, false);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, false);
   assistant_state()->NotifyFeatureAllowed(
-      chromeos::assistant::AssistantAllowedState::ALLOWED);
+      assistant::AssistantAllowedState::ALLOWED);
 
   ShelfNavigationWidget::TestApi test_api(
       GetPrimaryShelf()->navigation_widget());
diff --git a/ash/shelf/hotseat_widget_unittest.cc b/ash/shelf/hotseat_widget_unittest.cc
index d3b53de..8f0612a 100644
--- a/ash/shelf/hotseat_widget_unittest.cc
+++ b/ash/shelf/hotseat_widget_unittest.cc
@@ -105,9 +105,9 @@
     if (is_assistant_enabled_) {
       assistant_test_api_->SetAssistantEnabled(true);
       assistant_test_api_->GetAssistantState()->NotifyFeatureAllowed(
-          chromeos::assistant::AssistantAllowedState::ALLOWED);
+          assistant::AssistantAllowedState::ALLOWED);
       assistant_test_api_->GetAssistantState()->NotifyStatusChanged(
-          chromeos::assistant::AssistantStatus::READY);
+          assistant::AssistantStatus::READY);
 
       assistant_test_api_->WaitUntilIdle();
     }
@@ -138,7 +138,7 @@
     if (!navigation_buttons_shown_in_tablet_mode_ &&
         Shell::Get()->tablet_mode_controller()->InTabletMode()) {
       AssistantUiController::Get()->ShowUi(
-          chromeos::assistant::AssistantEntryPoint::kLongPressLauncher);
+          assistant::AssistantEntryPoint::kLongPressLauncher);
       return;
     }
 
diff --git a/ash/system/palette/palette_tray_unittest.cc b/ash/system/palette/palette_tray_unittest.cc
index 593326c..07bea882 100644
--- a/ash/system/palette/palette_tray_unittest.cc
+++ b/ash/system/palette/palette_tray_unittest.cc
@@ -395,12 +395,10 @@
   ui::ScopedAnimationDurationScaleMode animation_duration_mode(
       ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
   assistant_state()->NotifyFeatureAllowed(
-      chromeos::assistant::AssistantAllowedState::ALLOWED);
-  assistant_state()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, true);
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      true);
+      assistant::AssistantAllowedState::ALLOWED);
+  assistant_state()->NotifyStatusChanged(assistant::AssistantStatus::READY);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, true);
 
   ui::test::EventGenerator* generator = GetEventGenerator();
   generator->EnterPenPointerMode();
@@ -462,8 +460,7 @@
   // Disabling metalayer support in the delegate should disable the palette
   // tool.
   test_api_->palette_tool_manager()->ActivateTool(PaletteToolId::METALAYER);
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      false);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, false);
   EXPECT_FALSE(metalayer_enabled());
 
   // With the metalayer disabled again, press/drag does not activate the
@@ -476,11 +473,9 @@
 TEST_F(PaletteTrayTestWithAssistant, StylusBarrelButtonActivatesHighlighter) {
   ui::ScopedAnimationDurationScaleMode animation_duration_mode(
       ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
-  assistant_state()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::NOT_READY);
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, false);
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      false);
+  assistant_state()->NotifyStatusChanged(assistant::AssistantStatus::NOT_READY);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, false);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, false);
 
   ui::test::EventGenerator* generator = GetEventGenerator();
   generator->EnterPenPointerMode();
@@ -500,21 +495,19 @@
                              false /* no highlighter on press */);
 
   // Enable one of the two user prefs, should not be sufficient.
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, true);
   WaitDragAndAssertMetalayer("one pref enabled", origin,
                              ui::EF_LEFT_MOUSE_BUTTON, false /* no metalayer */,
                              false /* no highlighter on press */);
 
   // Enable the other user pref, still not sufficient.
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
   WaitDragAndAssertMetalayer("two prefs enabled", origin,
                              ui::EF_LEFT_MOUSE_BUTTON, false /* no metalayer */,
                              false /* no highlighter on press */);
 
   // Once the service is ready, the button should start working.
-  assistant_state()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  assistant_state()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   // Press and drag with no button, still no highlighter.
   WaitDragAndAssertMetalayer("all enabled, no button ", origin, ui::EF_NONE,
@@ -578,8 +571,7 @@
 
   // Disable the metalayer support.
   // This should deactivate both the palette tool and the highlighter.
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      false);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, false);
   EXPECT_FALSE(test_api_->palette_tool_manager()->IsToolActive(
       PaletteToolId::METALAYER));
 
diff --git a/ash/system/palette/tools/metalayer_mode.cc b/ash/system/palette/tools/metalayer_mode.cc
index e0bddd7..48a4dad 100644
--- a/ash/system/palette/tools/metalayer_mode.cc
+++ b/ash/system/palette/tools/metalayer_mode.cc
@@ -163,11 +163,11 @@
     // time.
     toast_event = kDeprecatedToastNotShown;
     if (!GetPrefs()->GetBoolean(
-            chromeos::assistant::prefs::kAssistantDeprecateStylusToast)) {
+            assistant::prefs::kAssistantDeprecateStylusToast)) {
       // Set the deprecate stylus toast assistant pref so that the toast doesn't
       // repeatedly show.
-      GetPrefs()->SetBoolean(
-          chromeos::assistant::prefs::kAssistantDeprecateStylusToast, true);
+      GetPrefs()->SetBoolean(assistant::prefs::kAssistantDeprecateStylusToast,
+                             true);
       Shell::Get()->toast_manager()->Show(
           ToastData(kDeprecateAssistantStylusToastId,
                     ToastCatalogName::kDeprecateAssistantStylus,
@@ -221,7 +221,7 @@
 }
 
 void MetalayerMode::OnAssistantStatusChanged(
-    chromeos::assistant::AssistantStatus status) {
+    assistant::AssistantStatus status) {
   assistant_status_ = status;
   UpdateState();
 }
@@ -237,7 +237,7 @@
 }
 
 void MetalayerMode::OnAssistantFeatureAllowedChanged(
-    chromeos::assistant::AssistantAllowedState state) {
+    assistant::AssistantAllowedState state) {
   assistant_allowed_state_ = state;
   UpdateState();
 }
diff --git a/ash/system/palette/tools/metalayer_mode.h b/ash/system/palette/tools/metalayer_mode.h
index ae01a04..9e1d627 100644
--- a/ash/system/palette/tools/metalayer_mode.h
+++ b/ash/system/palette/tools/metalayer_mode.h
@@ -57,20 +57,20 @@
   bool feature_enabled() const {
     return assistant_enabled_ && assistant_context_enabled_ &&
            assistant_allowed_state_ ==
-               chromeos::assistant::AssistantAllowedState::ALLOWED;
+               assistant::AssistantAllowedState::ALLOWED;
   }
 
   // Whether the tool is in "loading" state.
   bool loading() const {
     return feature_enabled() &&
-           assistant_status_ == chromeos::assistant::AssistantStatus::NOT_READY;
+           assistant_status_ == assistant::AssistantStatus::NOT_READY;
   }
 
   // Whether the tool can be selected from the menu (only true when enabled
   // by the user and fully loaded).
   bool selectable() const {
     return feature_enabled() &&
-           assistant_status_ != chromeos::assistant::AssistantStatus::NOT_READY;
+           assistant_status_ != assistant::AssistantStatus::NOT_READY;
   }
 
   // PaletteTool:
@@ -89,12 +89,11 @@
   void OnGestureEvent(ui::GestureEvent* event) override;
 
   // AssistantStateObserver:
-  void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus status) override;
+  void OnAssistantStatusChanged(assistant::AssistantStatus status) override;
   void OnAssistantSettingsEnabled(bool enabled) override;
   void OnAssistantContextEnabled(bool enabled) override;
   void OnAssistantFeatureAllowedChanged(
-      chromeos::assistant::AssistantAllowedState state) override;
+      assistant::AssistantAllowedState state) override;
 
   // HighlighterController::Observer:
   void OnHighlighterEnabledChanged(HighlighterEnabledState state) override;
@@ -108,15 +107,15 @@
   // Called when the metalayer session is complete.
   void OnMetalayerSessionComplete();
 
-  chromeos::assistant::AssistantStatus assistant_status_ =
-      chromeos::assistant::AssistantStatus::NOT_READY;
+  assistant::AssistantStatus assistant_status_ =
+      assistant::AssistantStatus::NOT_READY;
 
   bool assistant_enabled_ = false;
 
   bool assistant_context_enabled_ = false;
 
-  chromeos::assistant::AssistantAllowedState assistant_allowed_state_ =
-      chromeos::assistant::AssistantAllowedState::ALLOWED;
+  assistant::AssistantAllowedState assistant_allowed_state_ =
+      assistant::AssistantAllowedState::ALLOWED;
 
   base::TimeTicks previous_stroke_end_;
 
diff --git a/ash/system/palette/tools/metalayer_unittest.cc b/ash/system/palette/tools/metalayer_unittest.cc
index 5cb37e1..8a7c0ed 100644
--- a/ash/system/palette/tools/metalayer_unittest.cc
+++ b/ash/system/palette/tools/metalayer_unittest.cc
@@ -70,37 +70,32 @@
 // The metalayer tool is always visible, but only enabled when the user
 // has enabled the metalayer AND the Assistant framework is ready.
 TEST_F(MetalayerToolTest, PaletteMenuState) {
-  const chromeos::assistant::AssistantStatus kStates[] = {
-      chromeos::assistant::AssistantStatus::NOT_READY,
-      chromeos::assistant::AssistantStatus::READY};
-  const chromeos::assistant::AssistantAllowedState kAllowedStates[] = {
-      chromeos::assistant::AssistantAllowedState::ALLOWED,
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_POLICY,
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_LOCALE,
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER,
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_INCOGNITO,
+  const assistant::AssistantStatus kStates[] = {
+      assistant::AssistantStatus::NOT_READY, assistant::AssistantStatus::READY};
+  const assistant::AssistantAllowedState kAllowedStates[] = {
+      assistant::AssistantAllowedState::ALLOWED,
+      assistant::AssistantAllowedState::DISALLOWED_BY_POLICY,
+      assistant::AssistantAllowedState::DISALLOWED_BY_LOCALE,
+      assistant::AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER,
+      assistant::AssistantAllowedState::DISALLOWED_BY_INCOGNITO,
   };
   const std::u16string kLoading(u"loading");
 
   // Iterate over every possible combination of states.
-  for (chromeos::assistant::AssistantStatus state : kStates) {
-    for (chromeos::assistant::AssistantAllowedState allowed_state :
-         kAllowedStates) {
+  for (assistant::AssistantStatus state : kStates) {
+    for (assistant::AssistantAllowedState allowed_state : kAllowedStates) {
       for (int enabled = 0; enabled <= 1; enabled++) {
         for (int context = 0; context <= 1; context++) {
           const bool allowed =
-              allowed_state ==
-              chromeos::assistant::AssistantAllowedState::ALLOWED;
-          const bool ready =
-              state != chromeos::assistant::AssistantStatus::NOT_READY;
+              allowed_state == assistant::AssistantAllowedState::ALLOWED;
+          const bool ready = state != assistant::AssistantStatus::NOT_READY;
           const bool selectable = allowed && enabled && context && ready;
 
           assistant_state()->NotifyStatusChanged(state);
-          prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled,
-                              enabled);
+          prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, enabled);
           assistant_state()->NotifyFeatureAllowed(allowed_state);
-          prefs()->SetBoolean(
-              chromeos::assistant::prefs::kAssistantContextEnabled, context);
+          prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled,
+                              context);
 
           std::unique_ptr<views::View> view =
               base::WrapUnique(tool_->CreateView());
@@ -146,26 +141,23 @@
 
 // Verifies that disabling the metalayer support disables the tool.
 TEST_F(MetalayerToolTest, MetalayerUnsupportedDisablesPaletteTool) {
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, true);
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, true);
 
   // Disabling the user prefs individually should disable the tool.
   tool_->OnEnable();
   EXPECT_CALL(*palette_tool_delegate_.get(),
               DisableTool(PaletteToolId::METALAYER));
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, false);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, false);
   testing::Mock::VerifyAndClearExpectations(palette_tool_delegate_.get());
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantEnabled, true);
 
   tool_->OnEnable();
   EXPECT_CALL(*palette_tool_delegate_.get(),
               DisableTool(PaletteToolId::METALAYER));
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      false);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, false);
   testing::Mock::VerifyAndClearExpectations(palette_tool_delegate_.get());
-  prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                      true);
+  prefs()->SetBoolean(assistant::prefs::kAssistantContextEnabled, true);
 
   // Test AssistantState changes.
   tool_->OnEnable();
@@ -175,16 +167,14 @@
   EXPECT_CALL(*palette_tool_delegate_.get(),
               DisableTool(PaletteToolId::METALAYER))
       .Times(0);
-  assistant_state()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  assistant_state()->NotifyStatusChanged(assistant::AssistantStatus::READY);
   testing::Mock::VerifyAndClearExpectations(palette_tool_delegate_.get());
 
   // Changing the state to NOT_READY should disable the tool.
   EXPECT_CALL(*palette_tool_delegate_.get(),
               DisableTool(PaletteToolId::METALAYER))
       .Times(testing::AtLeast(1));
-  assistant_state()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::NOT_READY);
+  assistant_state()->NotifyStatusChanged(assistant::AssistantStatus::NOT_READY);
   testing::Mock::VerifyAndClearExpectations(palette_tool_delegate_.get());
 }
 
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index c56248f..71407db 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -6197,7 +6197,7 @@
 #if BUILDFLAG(IS_CHROMEOS_ASH)
     {"enable-assistant-dsp", flag_descriptions::kEnableGoogleAssistantDspName,
      flag_descriptions::kEnableGoogleAssistantDspDescription, kOsCrOS,
-     FEATURE_VALUE_TYPE(chromeos::assistant::features::kEnableDspHotword)},
+     FEATURE_VALUE_TYPE(ash::assistant::features::kEnableDspHotword)},
 
     {"deprecate-assistant-stylus-features",
      flag_descriptions::kDeprecateAssistantStylusFeaturesName,
@@ -6274,8 +6274,7 @@
     {"enable-assistant-stereo-input",
      flag_descriptions::kEnableGoogleAssistantStereoInputName,
      flag_descriptions::kEnableGoogleAssistantStereoInputDescription, kOsCrOS,
-     FEATURE_VALUE_TYPE(
-         chromeos::assistant::features::kEnableStereoAudioInput)},
+     FEATURE_VALUE_TYPE(ash::assistant::features::kEnableStereoAudioInput)},
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
     {"enable-gpu-service-logging",
@@ -6657,7 +6656,7 @@
     {"enable-assistant-routines",
      flag_descriptions::kEnableAssistantRoutinesName,
      flag_descriptions::kEnableAssistantRoutinesDescription, kOsCrOS,
-     FEATURE_VALUE_TYPE(chromeos::assistant::features::kAssistantRoutines)},
+     FEATURE_VALUE_TYPE(ash::assistant::features::kAssistantRoutines)},
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
 #if BUILDFLAG(IS_CHROMEOS_ASH)
@@ -6833,7 +6832,7 @@
      FEATURE_VALUE_TYPE(ash::features::kDeviceForceScheduledReboot)},
     {"enable-assistant-aec", flag_descriptions::kEnableGoogleAssistantAecName,
      flag_descriptions::kEnableGoogleAssistantAecDescription, kOsCrOS,
-     FEATURE_VALUE_TYPE(chromeos::assistant::features::kAssistantAudioEraser)},
+     FEATURE_VALUE_TYPE(ash::assistant::features::kAssistantAudioEraser)},
 #endif
 
 #if BUILDFLAG(IS_WIN)
diff --git a/chrome/browser/ash/assistant/assistant_util.cc b/chrome/browser/ash/assistant/assistant_util.cc
index 62de06f..3070ccb2 100644
--- a/chrome/browser/ash/assistant/assistant_util.cc
+++ b/chrome/browser/ash/assistant/assistant_util.cc
@@ -23,7 +23,7 @@
 
 namespace {
 
-using chromeos::assistant::AssistantAllowedState;
+using ::ash::assistant::AssistantAllowedState;
 
 bool g_override_is_google_device = false;
 
@@ -111,7 +111,7 @@
 
 bool IsAssistantDisabledByPolicy(const Profile* profile) {
   return profile->GetPrefs()->GetBoolean(
-      chromeos::assistant::prefs::kAssistantDisabledByPolicy);
+      ash::assistant::prefs::kAssistantDisabledByPolicy);
 }
 
 bool IsEmailDomainSupported(const Profile* profile) {
diff --git a/chrome/browser/ash/assistant/assistant_util.h b/chrome/browser/ash/assistant/assistant_util.h
index b9fd99b..b63cd90a 100644
--- a/chrome/browser/ash/assistant/assistant_util.h
+++ b/chrome/browser/ash/assistant/assistant_util.h
@@ -12,7 +12,7 @@
 namespace assistant {
 
 // Returns whether Google Assistant feature is allowed for given |profile|.
-chromeos::assistant::AssistantAllowedState IsAssistantAllowedForProfile(
+ash::assistant::AssistantAllowedState IsAssistantAllowedForProfile(
     const Profile* profile);
 
 void OverrideIsGoogleDeviceForTesting(bool is_google_device);
diff --git a/chrome/browser/ash/assistant/assistant_util_unittest.cc b/chrome/browser/ash/assistant/assistant_util_unittest.cc
index 42ca7349..18cf0b8 100644
--- a/chrome/browser/ash/assistant/assistant_util_unittest.cc
+++ b/chrome/browser/ash/assistant/assistant_util_unittest.cc
@@ -270,7 +270,7 @@
   ScopedLogIn login(GetFakeUserManager(), identity_test_env(),
                     GetGaiaUserAccountId(profile()));
 
-  EXPECT_EQ(chromeos::assistant::AssistantAllowedState::ALLOWED,
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::ALLOWED,
             IsAssistantAllowedForProfile(profile()));
 }
 
@@ -282,7 +282,7 @@
                                  GetGaiaUserAccountId(profile()));
 
   EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER,
+      ash::assistant::AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER,
       IsAssistantAllowedForProfile(profile()));
 }
 
@@ -291,7 +291,7 @@
                     GetGaiaUserAccountId(profile()),
                     user_manager::USER_TYPE_CHILD);
 
-  EXPECT_EQ(chromeos::assistant::AssistantAllowedState::ALLOWED,
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::ALLOWED,
             IsAssistantAllowedForProfile(profile()));
 }
 
@@ -300,7 +300,7 @@
                     GetGuestAccountId(), user_manager::USER_TYPE_GUEST);
 
   EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER,
+      ash::assistant::AssistantAllowedState::DISALLOWED_BY_NONPRIMARY_USER,
       IsAssistantAllowedForProfile(profile()));
 }
 
@@ -313,7 +313,7 @@
   ScopedLogIn login(GetFakeUserManager(), identity_test_env(),
                     GetGaiaUserAccountId(profile()));
 
-  EXPECT_EQ(chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_LOCALE,
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_LOCALE,
             IsAssistantAllowedForProfile(profile()));
   icu::Locale::setDefault(old_locale, error_code);
 }
@@ -324,7 +324,7 @@
   ScopedLogIn login(GetFakeUserManager(), identity_test_env(),
                     GetNonGaiaUserAccountId(profile()),
                     user_manager::USER_TYPE_PUBLIC_ACCOUNT);
-  EXPECT_EQ(chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_DEMO_MODE,
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_DEMO_MODE,
             IsAssistantAllowedForProfile(profile()));
 
   ash::DemoSession::SetDemoConfigForTesting(
@@ -335,9 +335,8 @@
   ScopedLogIn login(GetFakeUserManager(), identity_test_env(),
                     GetNonGaiaUserAccountId(profile()),
                     user_manager::USER_TYPE_PUBLIC_ACCOUNT);
-  EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_PUBLIC_SESSION,
-      IsAssistantAllowedForProfile(profile()));
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_PUBLIC_SESSION,
+            IsAssistantAllowedForProfile(profile()));
 }
 
 TEST_F(ChromeAssistantUtilTest, IsAssistantAllowedForProfile_NonGmail) {
@@ -345,16 +344,15 @@
       GetFakeUserManager(), identity_test_env(),
       GetGaiaUserAccountId("[email protected]", "0123456789"));
 
-  EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_ACCOUNT_TYPE,
-      IsAssistantAllowedForProfile(profile()));
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_ACCOUNT_TYPE,
+            IsAssistantAllowedForProfile(profile()));
 }
 
 TEST_F(ChromeAssistantUtilTest, IsAssistantAllowedForProfile_GoogleMail) {
   ScopedLogIn login(GetFakeUserManager(), identity_test_env(),
                     GetGaiaUserAccountId("[email protected]", "0123456789"));
 
-  EXPECT_EQ(chromeos::assistant::AssistantAllowedState::ALLOWED,
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::ALLOWED,
             IsAssistantAllowedForProfile(profile()));
 }
 
@@ -365,7 +363,7 @@
       GetGaiaUserAccountId("[email protected]", "0123456789"));
 
   ScopedSpoofGoogleBrandedDevice make_google_branded_device;
-  EXPECT_EQ(chromeos::assistant::AssistantAllowedState::ALLOWED,
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::ALLOWED,
             IsAssistantAllowedForProfile(profile()));
 }
 
@@ -375,9 +373,8 @@
                     GetActiveDirectoryUserAccountId(profile()),
                     user_manager::USER_TYPE_ACTIVE_DIRECTORY);
 
-  EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_ACCOUNT_TYPE,
-      IsAssistantAllowedForProfile(profile()));
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_ACCOUNT_TYPE,
+            IsAssistantAllowedForProfile(profile()));
 }
 
 TEST_F(ChromeAssistantUtilTest, IsAssistantAllowedForKiosk_KioskApp) {
@@ -385,9 +382,8 @@
                     GetNonGaiaUserAccountId(profile()),
                     user_manager::USER_TYPE_KIOSK_APP);
 
-  EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_KIOSK_MODE,
-      IsAssistantAllowedForProfile(profile()));
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_KIOSK_MODE,
+            IsAssistantAllowedForProfile(profile()));
 }
 
 TEST_F(ChromeAssistantUtilTest, IsAssistantAllowedForKiosk_ArcKioskApp) {
@@ -395,9 +391,8 @@
                     GetNonGaiaUserAccountId(profile()),
                     user_manager::USER_TYPE_ARC_KIOSK_APP);
 
-  EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_KIOSK_MODE,
-      IsAssistantAllowedForProfile(profile()));
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_KIOSK_MODE,
+            IsAssistantAllowedForProfile(profile()));
 }
 
 TEST_F(ChromeAssistantUtilTest, IsAssistantAllowedForKiosk_WebKioskApp) {
@@ -405,9 +400,8 @@
                     GetNonGaiaUserAccountId(profile()),
                     user_manager::USER_TYPE_WEB_KIOSK_APP);
 
-  EXPECT_EQ(
-      chromeos::assistant::AssistantAllowedState::DISALLOWED_BY_KIOSK_MODE,
-      IsAssistantAllowedForProfile(profile()));
+  EXPECT_EQ(ash::assistant::AssistantAllowedState::DISALLOWED_BY_KIOSK_MODE,
+            IsAssistantAllowedForProfile(profile()));
 }
 
 }  // namespace assistant
diff --git a/chrome/browser/ash/login/screens/assistant_optin_flow_screen.cc b/chrome/browser/ash/login/screens/assistant_optin_flow_screen.cc
index 454890a..da2df576 100644
--- a/chrome/browser/ash/login/screens/assistant_optin_flow_screen.cc
+++ b/chrome/browser/ash/login/screens/assistant_optin_flow_screen.cc
@@ -62,7 +62,7 @@
 
   if (::assistant::IsAssistantAllowedForProfile(
           ProfileManager::GetActiveUserProfile()) ==
-      chromeos::assistant::AssistantAllowedState::ALLOWED) {
+      assistant::AssistantAllowedState::ALLOWED) {
     return false;
   }
 
diff --git a/chrome/browser/ash/login/screens/assistant_optin_flow_screen_browsertest.cc b/chrome/browser/ash/login/screens/assistant_optin_flow_screen_browsertest.cc
index 3323a4b..1ae1039 100644
--- a/chrome/browser/ash/login/screens/assistant_optin_flow_screen_browsertest.cc
+++ b/chrome/browser/ash/login/screens/assistant_optin_flow_screen_browsertest.cc
@@ -49,9 +49,6 @@
 
 namespace ash {
 
-// TODO(https://crbug.com/1164001): remove when migrated to ash::
-namespace assistant = ::chromeos::assistant;
-
 namespace {
 
 using ::net::test_server::BasicHttpResponse;
@@ -109,7 +106,7 @@
 constexpr char kAssistantOptInScreenStepCompletionTime[] =
     "OOBE.StepCompletionTime.Assistant-optin-flow";
 
-class ScopedAssistantSettings : public chromeos::assistant::AssistantSettings {
+class ScopedAssistantSettings : public assistant::AssistantSettings {
  public:
   // Flags to configure GetSettings response.
   static constexpr int CONSENT_UI_FLAGS_NONE = 0;
@@ -191,7 +188,7 @@
     speaker_id_enrollment_state_ = SpeakerIdEnrollmentState::IDLE;
   }
 
-  // chromeos::assistant::AssistantSettings:
+  // assistant::AssistantSettings:
   void GetSettings(const std::string& selector,
                    GetSettingsCallback callback) override {}
 
@@ -201,7 +198,7 @@
     ASSERT_TRUE(selector_proto.ParseFromString(selector));
     EXPECT_FALSE(selector_proto.about_me_settings());
     EXPECT_TRUE(selector_proto.has_consent_flow_ui_selector());
-    EXPECT_EQ(assistant::ActivityControlSettingsUiSelector::
+    EXPECT_EQ(chromeos::assistant::ActivityControlSettingsUiSelector::
                   ASSISTANT_SUW_ONBOARDING_ON_CHROME_OS,
               selector_proto.consent_flow_ui_selector().flow_id());
 
@@ -276,12 +273,12 @@
                 update_proto.consent_flow_ui_update().consent_token());
       EXPECT_FALSE(
           update_proto.consent_flow_ui_update().saw_third_party_disclosure());
-      EXPECT_EQ(assistant::ActivityControlSettingsUiSelector::
+      EXPECT_EQ(chromeos::assistant::ActivityControlSettingsUiSelector::
                     ASSISTANT_SUW_ONBOARDING_ON_CHROME_OS,
                 update_proto.consent_flow_ui_update().flow_id());
       collected_optins_.insert(OptIn::ACTIVITY_CONTROL);
       update_result.mutable_consent_flow_update_result()->set_update_status(
-          assistant::ConsentFlowUiUpdateResult::SUCCESS);
+          chromeos::assistant::ConsentFlowUiUpdateResult::SUCCESS);
     }
     std::string message;
     EXPECT_TRUE(update_result.SerializeToString(&message));
@@ -290,8 +287,7 @@
 
   void StartSpeakerIdEnrollment(
       bool skip_cloud_enrollment,
-      base::WeakPtr<chromeos::assistant::SpeakerIdEnrollmentClient> client)
-      override {
+      base::WeakPtr<assistant::SpeakerIdEnrollmentClient> client) override {
     if (speaker_id_enrollment_mode_ == SpeakerIdEnrollmentMode::IMMEDIATE) {
       client->OnSpeakerIdEnrollmentDone();
       return;
@@ -474,8 +470,7 @@
 IN_PROC_BROWSER_TEST_F(AssistantOptInFlowTest, Basic) {
   auto force_lib_assistant_enabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(true);
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
@@ -514,8 +509,7 @@
 IN_PROC_BROWSER_TEST_F(AssistantOptInFlowTest, DisableScreenContext) {
   auto force_lib_assistant_enabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(true);
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
@@ -555,8 +549,7 @@
   OobeScreenWaiter screen_waiter(AssistantOptInFlowScreenView::kScreenId);
   screen_waiter.Wait();
 
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   test::OobeJS().CreateVisibilityWaiter(true, kAssistantValueProp)->Wait();
   TapWhenEnabled(kValuePropNextButton);
@@ -589,8 +582,7 @@
 
   ShowAssistantOptInFlowScreen();
 
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   OobeScreenWaiter screen_waiter(AssistantOptInFlowScreenView::kScreenId);
   screen_waiter.Wait();
@@ -627,8 +619,7 @@
   auto force_lib_assistant_enabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(true);
   SetUpAssistantScreensForTest();
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   ShowAssistantOptInFlowScreen();
 
@@ -659,8 +650,7 @@
       ScopedAssistantSettings::CONSENT_UI_FLAG_SKIP_ACTIVITY_CONTROL);
 
   SetUpAssistantScreensForTest();
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   ShowAssistantOptInFlowScreen();
 
@@ -696,8 +686,7 @@
       ScopedAssistantSettings::SpeakerIdEnrollmentMode::STEP_BY_STEP);
 
   SetUpAssistantScreensForTest();
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   ShowAssistantOptInFlowScreen();
 
@@ -766,8 +755,7 @@
       ScopedAssistantSettings::SpeakerIdEnrollmentMode::STEP_BY_STEP);
 
   SetUpAssistantScreensForTest();
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   ShowAssistantOptInFlowScreen();
 
@@ -814,8 +802,7 @@
       ScopedAssistantSettings::SpeakerIdEnrollmentMode::STEP_BY_STEP);
 
   SetUpAssistantScreensForTest();
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   ShowAssistantOptInFlowScreen();
 
@@ -867,8 +854,7 @@
   assistant_settings_->set_consent_ui_flags(
       ScopedAssistantSettings::CONSENT_UI_FLAG_WAA_DISABLED_BY_POLICY);
 
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
 
@@ -891,8 +877,7 @@
   assistant_settings_->set_consent_ui_flags(
       ScopedAssistantSettings::CONSENT_UI_FLAG_ASSISTANT_DISABLED_BY_POLICY);
 
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
 
@@ -913,8 +898,7 @@
 IN_PROC_BROWSER_TEST_F(AssistantOptInFlowTest, AssistantSkippedNoLib) {
   auto force_lib_assistant_disabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(false);
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
 
@@ -943,8 +927,7 @@
   auto force_lib_assistant_enabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(true);
   assistant_settings_->set_setting_zippy_size(2);
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
@@ -989,8 +972,7 @@
   auto force_lib_assistant_enabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(true);
   assistant_settings_->set_setting_zippy_size(2);
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
@@ -1021,8 +1003,7 @@
   auto force_lib_assistant_enabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(true);
   assistant_settings_->set_setting_zippy_size(2);
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
@@ -1059,8 +1040,7 @@
   auto force_lib_assistant_enabled =
       AssistantOptInFlowScreen::ForceLibAssistantEnabledForTesting(true);
   assistant_settings_->set_setting_zippy_size(2);
-  AssistantState::Get()->NotifyStatusChanged(
-      chromeos::assistant::AssistantStatus::READY);
+  AssistantState::Get()->NotifyStatusChanged(assistant::AssistantStatus::READY);
 
   SetUpAssistantScreensForTest();
   ShowAssistantOptInFlowScreen();
diff --git a/chrome/browser/ash/web_applications/help_app/help_app_untrusted_ui_config.cc b/chrome/browser/ash/web_applications/help_app/help_app_untrusted_ui_config.cc
index 0f8c89a..2508b42e 100644
--- a/chrome/browser/ash/web_applications/help_app/help_app_untrusted_ui_config.cc
+++ b/chrome/browser/ash/web_applications/help_app/help_app_untrusted_ui_config.cc
@@ -118,11 +118,11 @@
       !ui::DeviceDataManager::GetInstance()->GetTouchscreenDevices().empty());
   // Checks if the Google Assistant is allowed on this device by going through
   // policies.
-  chromeos::assistant::AssistantAllowedState assistant_allowed_state =
-      assistant::IsAssistantAllowedForProfile(profile);
-  source->AddBoolean("assistantAllowed",
-                     assistant_allowed_state ==
-                         chromeos::assistant::AssistantAllowedState::ALLOWED);
+  assistant::AssistantAllowedState assistant_allowed_state =
+      ::assistant::IsAssistantAllowedForProfile(profile);
+  source->AddBoolean(
+      "assistantAllowed",
+      assistant_allowed_state == assistant::AssistantAllowedState::ALLOWED);
   source->AddBoolean("assistantEnabled",
                      AssistantState::Get()->settings_enabled().value_or(false));
   source->AddBoolean("playStoreEnabled",
diff --git a/chrome/browser/extensions/api/settings_private/prefs_util.cc b/chrome/browser/extensions/api/settings_private/prefs_util.cc
index 75975b4..4e2acc7 100644
--- a/chrome/browser/extensions/api/settings_private/prefs_util.cc
+++ b/chrome/browser/extensions/api/settings_private/prefs_util.cc
@@ -587,24 +587,23 @@
       settings_api::PrefType::PREF_TYPE_NUMBER;
 
   // Google Assistant.
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantConsentStatus] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantConsentStatus] =
       settings_api::PrefType::PREF_TYPE_NUMBER;
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantDisabledByPolicy] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantDisabledByPolicy] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantEnabled] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantEnabled] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantContextEnabled] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantContextEnabled] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantHotwordAlwaysOn] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantHotwordAlwaysOn] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantHotwordEnabled] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantHotwordEnabled] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
-  (*s_allowlist)
-      [chromeos::assistant::prefs::kAssistantVoiceMatchEnabledDuringOobe] =
-          settings_api::PrefType::PREF_TYPE_BOOLEAN;
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantLaunchWithMicOpen] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantVoiceMatchEnabledDuringOobe] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
-  (*s_allowlist)[chromeos::assistant::prefs::kAssistantNotificationEnabled] =
+  (*s_allowlist)[ash::assistant::prefs::kAssistantLaunchWithMicOpen] =
+      settings_api::PrefType::PREF_TYPE_BOOLEAN;
+  (*s_allowlist)[ash::assistant::prefs::kAssistantNotificationEnabled] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
 
   // Quick Answers.
@@ -1256,7 +1255,7 @@
 
 bool PrefsUtil::IsHotwordDisabledForChildUser(const std::string& pref_name) {
   const std::string& hotwordEnabledPref =
-      chromeos::assistant::prefs::kAssistantHotwordEnabled;
+      ash::assistant::prefs::kAssistantHotwordEnabled;
   if (!profile_->IsChild() || pref_name != hotwordEnabledPref)
     return false;
 
diff --git a/chrome/browser/metrics/assistant_service_metrics_provider.cc b/chrome/browser/metrics/assistant_service_metrics_provider.cc
index aa896949..633a4b8 100644
--- a/chrome/browser/metrics/assistant_service_metrics_provider.cc
+++ b/chrome/browser/metrics/assistant_service_metrics_provider.cc
@@ -17,17 +17,17 @@
     metrics::ChromeUserMetricsExtension* uma_proto_unused) {
   if (assistant::IsAssistantAllowedForProfile(
           ProfileManager::GetActiveUserProfile()) !=
-      chromeos::assistant::AssistantAllowedState::ALLOWED) {
+      ash::assistant::AssistantAllowedState::ALLOWED) {
     return;
   }
 
   UMA_HISTOGRAM_BOOLEAN(
       "Assistant.ServiceEnabledUserCount",
       ProfileManager::GetActiveUserProfile()->GetPrefs()->GetBoolean(
-          chromeos::assistant::prefs::kAssistantEnabled));
+          ash::assistant::prefs::kAssistantEnabled));
 
   UMA_HISTOGRAM_BOOLEAN(
       "Assistant.ContextEnabledUserCount",
       ProfileManager::GetActiveUserProfile()->GetPrefs()->GetBoolean(
-          chromeos::assistant::prefs::kAssistantContextEnabled));
+          ash::assistant::prefs::kAssistantContextEnabled));
 }
diff --git a/chrome/browser/policy/configuration_policy_handler_list_factory.cc b/chrome/browser/policy/configuration_policy_handler_list_factory.cc
index 12e43f47..55fa452 100644
--- a/chrome/browser/policy/configuration_policy_handler_list_factory.cc
+++ b/chrome/browser/policy/configuration_policy_handler_list_factory.cc
@@ -1118,16 +1118,16 @@
     plugin_vm::prefs::kPluginVmRequiredFreeDiskSpaceGB,
     base::Value::Type::INTEGER },
   { key::kAssistantOnboardingMode,
-    chromeos::assistant::prefs::kAssistantOnboardingMode,
+    ash::assistant::prefs::kAssistantOnboardingMode,
     base::Value::Type::STRING },
   { key::kAssistantVoiceMatchEnabledDuringOobe,
-    chromeos::assistant::prefs::kAssistantVoiceMatchEnabledDuringOobe,
+    ash::assistant::prefs::kAssistantVoiceMatchEnabledDuringOobe,
     base::Value::Type::BOOLEAN },
   { key::kVoiceInteractionContextEnabled,
-    chromeos::assistant::prefs::kAssistantContextEnabled,
+    ash::assistant::prefs::kAssistantContextEnabled,
     base::Value::Type::BOOLEAN },
   { key::kVoiceInteractionHotwordEnabled,
-    chromeos::assistant::prefs::kAssistantHotwordEnabled,
+    ash::assistant::prefs::kAssistantHotwordEnabled,
     base::Value::Type::BOOLEAN },
   { key::kDevicePowerPeakShiftEnabled,
     ash::prefs::kPowerPeakShiftEnabled,
diff --git a/chrome/browser/policy/test/assistant_policy_browsertest.cc b/chrome/browser/policy/test/assistant_policy_browsertest.cc
index 295ee564..2325855 100644
--- a/chrome/browser/policy/test/assistant_policy_browsertest.cc
+++ b/chrome/browser/policy/test/assistant_policy_browsertest.cc
@@ -18,12 +18,12 @@
 IN_PROC_BROWSER_TEST_F(AssistantPolicyTest, AssistantContextEnabled) {
   PrefService* prefs = browser()->profile()->GetPrefs();
   EXPECT_FALSE(prefs->IsManagedPreference(
-      chromeos::assistant::prefs::kAssistantContextEnabled));
+      ash::assistant::prefs::kAssistantContextEnabled));
   EXPECT_FALSE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled));
-  prefs->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled, true);
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantContextEnabled));
+  prefs->SetBoolean(ash::assistant::prefs::kAssistantContextEnabled, true);
   EXPECT_TRUE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled));
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantContextEnabled));
 
   // Verifies that the Assistant context can be forced to always disabled.
   PolicyMap policies;
@@ -32,12 +32,12 @@
                nullptr);
   UpdateProviderPolicy(policies);
   EXPECT_TRUE(prefs->IsManagedPreference(
-      chromeos::assistant::prefs::kAssistantContextEnabled));
+      ash::assistant::prefs::kAssistantContextEnabled));
   EXPECT_FALSE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled));
-  prefs->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled, true);
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantContextEnabled));
+  prefs->SetBoolean(ash::assistant::prefs::kAssistantContextEnabled, true);
   EXPECT_FALSE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled));
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantContextEnabled));
 
   // Verifies that the Assistant context can be forced to always enabled.
   policies.Set(key::kVoiceInteractionContextEnabled, POLICY_LEVEL_MANDATORY,
@@ -45,24 +45,23 @@
                nullptr);
   UpdateProviderPolicy(policies);
   EXPECT_TRUE(prefs->IsManagedPreference(
-      chromeos::assistant::prefs::kAssistantContextEnabled));
+      ash::assistant::prefs::kAssistantContextEnabled));
   EXPECT_TRUE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled));
-  prefs->SetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled,
-                    false);
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantContextEnabled));
+  prefs->SetBoolean(ash::assistant::prefs::kAssistantContextEnabled, false);
   EXPECT_TRUE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantContextEnabled));
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantContextEnabled));
 }
 
 IN_PROC_BROWSER_TEST_F(AssistantPolicyTest, AssistantHotwordEnabled) {
   PrefService* prefs = browser()->profile()->GetPrefs();
   EXPECT_FALSE(prefs->IsManagedPreference(
-      chromeos::assistant::prefs::kAssistantHotwordEnabled));
+      ash::assistant::prefs::kAssistantHotwordEnabled));
   EXPECT_FALSE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled));
-  prefs->SetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled, true);
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled));
+  prefs->SetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled, true);
   EXPECT_TRUE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled));
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled));
 
   // Verifies that the Assistant hotword can be forced to always disabled.
   PolicyMap policies;
@@ -71,12 +70,12 @@
                nullptr);
   UpdateProviderPolicy(policies);
   EXPECT_TRUE(prefs->IsManagedPreference(
-      chromeos::assistant::prefs::kAssistantHotwordEnabled));
+      ash::assistant::prefs::kAssistantHotwordEnabled));
   EXPECT_FALSE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled));
-  prefs->SetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled, true);
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled));
+  prefs->SetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled, true);
   EXPECT_FALSE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled));
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled));
 
   // Verifies that the Assistant hotword can be forced to always enabled.
   policies.Set(key::kVoiceInteractionHotwordEnabled, POLICY_LEVEL_MANDATORY,
@@ -84,13 +83,12 @@
                nullptr);
   UpdateProviderPolicy(policies);
   EXPECT_TRUE(prefs->IsManagedPreference(
-      chromeos::assistant::prefs::kAssistantHotwordEnabled));
+      ash::assistant::prefs::kAssistantHotwordEnabled));
   EXPECT_TRUE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled));
-  prefs->SetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled,
-                    false);
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled));
+  prefs->SetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled, false);
   EXPECT_TRUE(
-      prefs->GetBoolean(chromeos::assistant::prefs::kAssistantHotwordEnabled));
+      prefs->GetBoolean(ash::assistant::prefs::kAssistantHotwordEnabled));
 }
 
 }  // namespace policy
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index b290799..5fe15ec 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -1511,7 +1511,7 @@
   ash::ApkWebAppService::RegisterProfilePrefs(registry);
   ash::app_time::AppActivityRegistry::RegisterProfilePrefs(registry);
   ash::app_time::AppTimeController::RegisterProfilePrefs(registry);
-  chromeos::assistant::prefs::RegisterProfilePrefs(registry);
+  ash::assistant::prefs::RegisterProfilePrefs(registry);
   ash::bluetooth::DebugLogsManager::RegisterPrefs(registry);
   chromeos::bluetooth_config::BluetoothPowerControllerImpl::
       RegisterProfilePrefs(registry);
diff --git a/chrome/browser/ui/app_list/search/assistant_text_search_provider.cc b/chrome/browser/ui/app_list/search/assistant_text_search_provider.cc
index 90f78a25..4a118cc 100644
--- a/chrome/browser/ui/app_list/search/assistant_text_search_provider.cc
+++ b/chrome/browser/ui/app_list/search/assistant_text_search_provider.cc
@@ -27,7 +27,7 @@
 
 namespace {
 
-using chromeos::assistant::AssistantAllowedState;
+using ::ash::assistant::AssistantAllowedState;
 
 constexpr char kIdPrefix[] = "googleassistant_text://";
 
@@ -113,7 +113,7 @@
 }
 
 void AssistantTextSearchProvider::OnAssistantFeatureAllowedChanged(
-    chromeos::assistant::AssistantAllowedState allowed_state) {
+    AssistantAllowedState allowed_state) {
   UpdateResults();
 }
 
diff --git a/chrome/browser/ui/app_list/search/assistant_text_search_provider.h b/chrome/browser/ui/app_list/search/assistant_text_search_provider.h
index f5a0033..cfb3ff90 100644
--- a/chrome/browser/ui/app_list/search/assistant_text_search_provider.h
+++ b/chrome/browser/ui/app_list/search/assistant_text_search_provider.h
@@ -40,7 +40,7 @@
 
   // ash::AssistantStateObserver:
   void OnAssistantFeatureAllowedChanged(
-      chromeos::assistant::AssistantAllowedState allowed_state) override;
+      ash::assistant::AssistantAllowedState allowed_state) override;
   void OnAssistantSettingsEnabled(bool enabled) override;
 
   // Invoke to update results based on current state.
diff --git a/chrome/browser/ui/app_list/search/assistant_text_search_provider_unittest.cc b/chrome/browser/ui/app_list/search/assistant_text_search_provider_unittest.cc
index 441523a..e9c81da 100644
--- a/chrome/browser/ui/app_list/search/assistant_text_search_provider_unittest.cc
+++ b/chrome/browser/ui/app_list/search/assistant_text_search_provider_unittest.cc
@@ -21,7 +21,7 @@
 namespace app_list {
 namespace {
 
-using chromeos::assistant::AssistantAllowedState;
+using ::ash::assistant::AssistantAllowedState;
 
 // Parameterized by feature ProductivityLauncher.
 class AssistantTextSearchProviderTest
diff --git a/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.cc b/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.cc
index e38c5d49..7892a10 100644
--- a/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.cc
+++ b/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.cc
@@ -59,7 +59,7 @@
 
 void AssistantBrowserDelegateImpl::MaybeInit(Profile* profile) {
   if (assistant::IsAssistantAllowedForProfile(profile) !=
-      chromeos::assistant::AssistantAllowedState::ALLOWED) {
+      ash::assistant::AssistantAllowedState::ALLOWED) {
     return;
   }
 
@@ -98,11 +98,11 @@
   if (!initialized_)
     return;
 
-  chromeos::assistant::AssistantService::Get()->Shutdown();
+  ash::assistant::AssistantService::Get()->Shutdown();
 }
 
 void AssistantBrowserDelegateImpl::OnAssistantStatusChanged(
-    chromeos::assistant::AssistantStatus new_status) {
+    ash::assistant::AssistantStatus new_status) {
   ash::AssistantState::Get()->NotifyStatusChanged(new_status);
 }
 
@@ -214,7 +214,7 @@
 }
 
 void AssistantBrowserDelegateImpl::OnAssistantFeatureAllowedChanged(
-    chromeos::assistant::AssistantAllowedState allowed_state) {
+    ash::assistant::AssistantAllowedState allowed_state) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
 
   MaybeInit(profile);
diff --git a/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.h b/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.h
index 305117f..31158bc5 100644
--- a/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.h
+++ b/chrome/browser/ui/ash/assistant/assistant_browser_delegate_impl.h
@@ -26,7 +26,7 @@
 
 // Class to handle all Assistant in-browser-process functionalities.
 class AssistantBrowserDelegateImpl
-    : public chromeos::assistant::AssistantBrowserDelegate,
+    : public ash::assistant::AssistantBrowserDelegate,
       public signin::IdentityManager::Observer,
       public session_manager::SessionManagerObserver,
       public ash::AssistantStateObserver {
@@ -42,7 +42,7 @@
 
   // chromeos::assistant::AssisantClient overrides:
   void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus new_status) override;
+      ash::assistant::AssistantStatus new_status) override;
   void RequestAssistantVolumeControl(
       mojo::PendingReceiver<ash::mojom::AssistantVolumeControl> receiver)
       override;
@@ -87,7 +87,7 @@
 
   // ash::AssistantStateObserver:
   void OnAssistantFeatureAllowedChanged(
-      chromeos::assistant::AssistantAllowedState allowed_state) override;
+      ash::assistant::AssistantAllowedState allowed_state) override;
 
   // Called when the application is terminating
   void OnAppTerminating();
diff --git a/chrome/browser/ui/ash/assistant/assistant_browsertest.cc b/chrome/browser/ui/ash/assistant/assistant_browsertest.cc
index f7b7462d..134d585 100644
--- a/chrome/browser/ui/ash/assistant/assistant_browsertest.cc
+++ b/chrome/browser/ui/ash/assistant/assistant_browsertest.cc
@@ -58,7 +58,7 @@
   AssistantBrowserTest() {
     // TODO(b/190633242): enable sandbox in browser tests.
     feature_list_.InitAndDisableFeature(
-        chromeos::assistant::features::kEnableLibAssistantSandbox);
+        ash::assistant::features::kEnableLibAssistantSandbox);
 
     // Do not log to file in test. Otherwise multiple tests may create/delete
     // the log file at the same time. See http://crbug.com/1307868.
diff --git a/chrome/browser/ui/ash/assistant/assistant_setup.cc b/chrome/browser/ui/ash/assistant/assistant_setup.cc
index 12e17bb..3b291a9 100644
--- a/chrome/browser/ui/ash/assistant/assistant_setup.cc
+++ b/chrome/browser/ui/ash/assistant/assistant_setup.cc
@@ -37,7 +37,7 @@
 AssistantSetup::AssistantSetup() {
   DCHECK(assistant::IsAssistantAllowedForProfile(
              ProfileManager::GetActiveUserProfile()) ==
-         chromeos::assistant::AssistantAllowedState::ALLOWED);
+         ash::assistant::AssistantAllowedState::ALLOWED);
   ash::AssistantState::Get()->AddObserver(this);
 
   search_and_assistant_enabled_checker_ =
@@ -64,7 +64,7 @@
 void AssistantSetup::MaybeStartAssistantOptInFlow() {
   DCHECK(Prefs());
   if (!Prefs()->GetUserPrefValue(
-          chromeos::assistant::prefs::kAssistantConsentStatus)) {
+          ash::assistant::prefs::kAssistantConsentStatus)) {
     base::SequencedTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::BindOnce(&AssistantSetup::StartAssistantOptInFlow,
@@ -77,24 +77,24 @@
   // When there is an error, default the pref to false if the pref is not set
   // yet. The pref value will be synced the next time.
   if (!Prefs()->GetUserPrefValue(
-          chromeos::assistant::prefs::kAssistantDisabledByPolicy)) {
-    Prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantDisabledByPolicy,
+          ash::assistant::prefs::kAssistantDisabledByPolicy)) {
+    Prefs()->SetBoolean(ash::assistant::prefs::kAssistantDisabledByPolicy,
                         false);
   }
 }
 
 void AssistantSetup::OnSearchAndAssistantStateReceived(bool is_disabled) {
-  Prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantDisabledByPolicy,
+  Prefs()->SetBoolean(ash::assistant::prefs::kAssistantDisabledByPolicy,
                       is_disabled);
   if (is_disabled) {
     DVLOG(1) << "Assistant is disabled by domain policy.";
-    Prefs()->SetBoolean(chromeos::assistant::prefs::kAssistantEnabled, false);
+    Prefs()->SetBoolean(ash::assistant::prefs::kAssistantEnabled, false);
   }
 }
 
 void AssistantSetup::OnAssistantStatusChanged(
-    chromeos::assistant::AssistantStatus status) {
-  if (status == chromeos::assistant::AssistantStatus::NOT_READY)
+    ash::assistant::AssistantStatus status) {
+  if (status == ash::assistant::AssistantStatus::NOT_READY)
     return;
 
   SyncSettingsState();
@@ -107,7 +107,7 @@
   consent_flow_ui->set_flow_id(
       chromeos::assistant::ActivityControlSettingsUiSelector::
           ASSISTANT_SUW_ONBOARDING_ON_CHROME_OS);
-  chromeos::assistant::AssistantSettings::Get()->GetSettings(
+  ash::assistant::AssistantSettings::Get()->GetSettings(
       selector.SerializeAsString(),
       base::BindOnce(&AssistantSetup::OnGetSettingsResponse,
                      base::Unretained(this)));
@@ -129,29 +129,27 @@
     case ConsentFlowUi::ASK_FOR_CONSENT:
       if (consent_ui.has_activity_control_ui() &&
           consent_ui.activity_control_ui().setting_zippy().size()) {
-        Prefs()->SetInteger(
-            chromeos::assistant::prefs::kAssistantConsentStatus,
-            chromeos::assistant::prefs::ConsentStatus::kNotFound);
+        Prefs()->SetInteger(ash::assistant::prefs::kAssistantConsentStatus,
+                            ash::assistant::prefs::ConsentStatus::kNotFound);
       } else {
-        Prefs()->SetInteger(chromeos::assistant::prefs::kAssistantConsentStatus,
-                            chromeos::assistant::prefs::ConsentStatus::
-                                kActivityControlAccepted);
+        Prefs()->SetInteger(
+            ash::assistant::prefs::kAssistantConsentStatus,
+            ash::assistant::prefs::ConsentStatus::kActivityControlAccepted);
       }
       break;
     case ConsentFlowUi::ERROR_ACCOUNT:
-      Prefs()->SetInteger(
-          chromeos::assistant::prefs::kAssistantConsentStatus,
-          chromeos::assistant::prefs::ConsentStatus::kUnauthorized);
+      Prefs()->SetInteger(ash::assistant::prefs::kAssistantConsentStatus,
+                          ash::assistant::prefs::ConsentStatus::kUnauthorized);
       break;
     case ConsentFlowUi::ALREADY_CONSENTED:
       Prefs()->SetInteger(
-          chromeos::assistant::prefs::kAssistantConsentStatus,
-          chromeos::assistant::prefs::ConsentStatus::kActivityControlAccepted);
+          ash::assistant::prefs::kAssistantConsentStatus,
+          ash::assistant::prefs::ConsentStatus::kActivityControlAccepted);
       break;
     case ConsentFlowUi::UNSPECIFIED:
     case ConsentFlowUi::ERROR:
-      Prefs()->SetInteger(chromeos::assistant::prefs::kAssistantConsentStatus,
-                          chromeos::assistant::prefs::ConsentStatus::kUnknown);
+      Prefs()->SetInteger(ash::assistant::prefs::kAssistantConsentStatus,
+                          ash::assistant::prefs::ConsentStatus::kUnknown);
       LOG(ERROR) << "Invalid activity control consent status.";
   }
 }
diff --git a/chrome/browser/ui/ash/assistant/assistant_setup.h b/chrome/browser/ui/ash/assistant/assistant_setup.h
index 2165ee36..f7962c6 100644
--- a/chrome/browser/ui/ash/assistant/assistant_setup.h
+++ b/chrome/browser/ui/ash/assistant/assistant_setup.h
@@ -44,7 +44,7 @@
  private:
   // ash::AssistantStateObserver:
   void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus status) override;
+      ash::assistant::AssistantStatus status) override;
 
   void SyncSettingsState();
   void OnGetSettingsResponse(const std::string& settings);
diff --git a/chrome/browser/ui/ash/assistant/assistant_state_client.cc b/chrome/browser/ui/ash/assistant/assistant_state_client.cc
index cb84392..fbb3e02 100644
--- a/chrome/browser/ui/ash/assistant/assistant_state_client.cc
+++ b/chrome/browser/ui/ash/assistant/assistant_state_client.cc
@@ -32,7 +32,7 @@
 
 void AssistantStateClient::NotifyFeatureAllowed() {
   DCHECK(profile_);
-  chromeos::assistant::AssistantAllowedState state =
+  ash::assistant::AssistantAllowedState state =
       assistant::IsAssistantAllowedForProfile(profile_);
   ash::AssistantState::Get()->NotifyFeatureAllowed(state);
 }
@@ -88,7 +88,7 @@
                           base::Unretained(this)));
 
   pref_change_registrar_->Add(
-      chromeos::assistant::prefs::kAssistantDisabledByPolicy,
+      ash::assistant::prefs::kAssistantDisabledByPolicy,
       base::BindRepeating(&AssistantStateClient::NotifyFeatureAllowed,
                           base::Unretained(this)));
 
diff --git a/chrome/browser/ui/ash/assistant/assistant_test_mixin.cc b/chrome/browser/ui/ash/assistant/assistant_test_mixin.cc
index 3f81e02..080e02e 100644
--- a/chrome/browser/ui/ash/assistant/assistant_test_mixin.cc
+++ b/chrome/browser/ui/ash/assistant/assistant_test_mixin.cc
@@ -51,7 +51,7 @@
 class AssistantStatusWaiter : private ash::AssistantStateObserver {
  public:
   AssistantStatusWaiter(ash::AssistantState* state,
-                        chromeos::assistant::AssistantStatus expected_status)
+                        ash::assistant::AssistantStatus expected_status)
       : state_(state), expected_status_(expected_status) {
     state_->AddObserver(this);
   }
@@ -74,13 +74,13 @@
 
  private:
   void OnAssistantStatusChanged(
-      chromeos::assistant::AssistantStatus status) override {
+      ash::assistant::AssistantStatus status) override {
     if (status == expected_status_ && quit_loop_)
       std::move(quit_loop_).Run();
   }
 
   ash::AssistantState* const state_;
-  chromeos::assistant::AssistantStatus const expected_status_;
+  ash::assistant::AssistantStatus const expected_status_;
 
   base::OnceClosure quit_loop_;
 };
@@ -420,7 +420,7 @@
   SetPreferVoice(false);
 
   AssistantStatusWaiter waiter(test_api_->GetAssistantState(),
-                               chromeos::assistant::AssistantStatus::READY);
+                               ash::assistant::AssistantStatus::READY);
   waiter.RunUntilExpectedStatus();
 }
 
@@ -591,7 +591,7 @@
 
   // Then wait for the Service to shutdown.
   AssistantStatusWaiter waiter(test_api_->GetAssistantState(),
-                               chromeos::assistant::AssistantStatus::NOT_READY);
+                               ash::assistant::AssistantStatus::NOT_READY);
   waiter.RunUntilExpectedStatus();
 }
 
diff --git a/chrome/browser/ui/ash/assistant/assistant_timers_browsertest.cc b/chrome/browser/ui/ash/assistant/assistant_timers_browsertest.cc
index fda4c65..51c9abb 100644
--- a/chrome/browser/ui/ash/assistant/assistant_timers_browsertest.cc
+++ b/chrome/browser/ui/ash/assistant/assistant_timers_browsertest.cc
@@ -195,7 +195,7 @@
   AssistantTimersBrowserTest() {
     // TODO(b/190633242): enable sandbox in browser tests.
     feature_list_.InitAndDisableFeature(
-        chromeos::assistant::features::kEnableLibAssistantSandbox);
+        ash::assistant::features::kEnableLibAssistantSandbox);
 
     // Do not log to file in test. Otherwise multiple tests may create/delete
     // the log file at the same time. See http://crbug.com/1307868.
diff --git a/chrome/browser/ui/ash/assistant/device_actions.cc b/chrome/browser/ui/ash/assistant/device_actions.cc
index c8ae9b4..582e785 100644
--- a/chrome/browser/ui/ash/assistant/device_actions.cc
+++ b/chrome/browser/ui/ash/assistant/device_actions.cc
@@ -101,8 +101,7 @@
 }
 
 void NotifyAndroidAppListRefreshed(
-    base::ObserverList<chromeos::assistant::AppListEventSubscriber>*
-        subscribers) {
+    base::ObserverList<ash::assistant::AppListEventSubscriber>* subscribers) {
   std::vector<AndroidAppInfo> android_apps_info = GetAppsInfo();
   for (auto& subscriber : *subscribers)
     subscriber.OnAndroidAppListRefreshed(android_apps_info);
@@ -232,7 +231,7 @@
 }
 
 void DeviceActions::AddAndFireAppListEventSubscriber(
-    chromeos::assistant::AppListEventSubscriber* subscriber) {
+    ash::assistant::AppListEventSubscriber* subscriber) {
   auto* prefs = ArcAppListPrefs::Get(ProfileManager::GetActiveUserProfile());
   if (prefs && prefs->package_list_initial_refreshed()) {
     std::vector<AndroidAppInfo> android_apps_info = GetAppsInfo();
@@ -246,7 +245,7 @@
 }
 
 void DeviceActions::RemoveAppListEventSubscriber(
-    chromeos::assistant::AppListEventSubscriber* subscriber) {
+    ash::assistant::AppListEventSubscriber* subscriber) {
   app_list_subscribers_.RemoveObserver(subscriber);
 }
 
diff --git a/chrome/browser/ui/ash/assistant/device_actions.h b/chrome/browser/ui/ash/assistant/device_actions.h
index c79ef5ae..2019fb0 100644
--- a/chrome/browser/ui/ash/assistant/device_actions.h
+++ b/chrome/browser/ui/ash/assistant/device_actions.h
@@ -21,7 +21,7 @@
 #include "mojo/public/cpp/bindings/remote_set.h"
 
 class DeviceActions : public ash::AndroidIntentHelper,
-                      public chromeos::assistant::DeviceActions,
+                      public ash::assistant::DeviceActions,
                       public ArcAppListPrefs::Observer {
  public:
   explicit DeviceActions(std::unique_ptr<DeviceActionsDelegate> delegate);
@@ -31,7 +31,7 @@
 
   ~DeviceActions() override;
 
-  // chromeos::assistant::DeviceActions overrides:
+  // ash::assistant::DeviceActions overrides:
   void SetWifiEnabled(bool enabled) override;
   void SetBluetoothEnabled(bool enabled) override;
   void GetScreenBrightnessLevel(
@@ -45,9 +45,9 @@
       const chromeos::assistant::AndroidAppInfo& app_info) override;
   void LaunchAndroidIntent(const std::string& intent) override;
   void AddAndFireAppListEventSubscriber(
-      chromeos::assistant::AppListEventSubscriber* subscriber) override;
+      ash::assistant::AppListEventSubscriber* subscriber) override;
   void RemoveAppListEventSubscriber(
-      chromeos::assistant::AppListEventSubscriber* subscriber) override;
+      ash::assistant::AppListEventSubscriber* subscriber) override;
 
   // ash::AndroidIntentHelper overrides:
   absl::optional<std::string> GetAndroidAppLaunchIntent(
@@ -64,7 +64,7 @@
 
   base::ScopedMultiSourceObservation<ArcAppListPrefs, ArcAppListPrefs::Observer>
       scoped_prefs_observations_{this};
-  base::ObserverList<chromeos::assistant::AppListEventSubscriber>
+  base::ObserverList<ash::assistant::AppListEventSubscriber>
       app_list_subscribers_;
 
   mojo::Remote<chromeos::bluetooth_config::mojom::CrosBluetoothConfig>
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate.cc b/chrome/browser/ui/ash/chrome_shell_delegate.cc
index 5ae33e5..b70e755f 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate.cc
@@ -258,7 +258,7 @@
   }
 
   if (assistant::IsAssistantAllowedForProfile(profile) ==
-      chromeos::assistant::AssistantAllowedState::ALLOWED) {
+      ash::assistant::AssistantAllowedState::ALLOWED) {
     ash::AssistantState::Get()->NotifyLockedFullScreenStateChanged(locked);
   }
 }
diff --git a/chromeos/ash/services/assistant/device_settings_host.h b/chromeos/ash/services/assistant/device_settings_host.h
index 999e769..ef46bbd 100644
--- a/chromeos/ash/services/assistant/device_settings_host.h
+++ b/chromeos/ash/services/assistant/device_settings_host.h
@@ -6,6 +6,8 @@
 #define CHROMEOS_ASH_SERVICES_ASSISTANT_DEVICE_SETTINGS_HOST_H_
 
 #include "base/component_export.h"
+// TODO(https://crbug.com/1164001): move to forward declaration
+#include "chromeos/ash/services/assistant/public/cpp/device_actions.h"
 #include "chromeos/services/libassistant/public/mojom/device_settings_delegate.mojom.h"
 #include "mojo/public/cpp/bindings/pending_receiver.h"
 #include "mojo/public/cpp/bindings/receiver.h"
@@ -17,7 +19,6 @@
 namespace chromeos {
 namespace assistant {
 
-class DeviceActions;
 class ServiceContext;
 
 class COMPONENT_EXPORT(ASSISTANT_SERVICE) DeviceSettingsHost
diff --git a/chromeos/ash/services/assistant/media_host.h b/chromeos/ash/services/assistant/media_host.h
index 5fd4aca..2f89472 100644
--- a/chromeos/ash/services/assistant/media_host.h
+++ b/chromeos/ash/services/assistant/media_host.h
@@ -8,6 +8,10 @@
 #include "base/component_export.h"
 #include "base/observer_list.h"
 #include "base/unguessable_token.h"
+// TODO(https://crbug.com/1164001): move to forward declaration
+#include "chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.h"
+// TODO(https://crbug.com/1164001): move to forward declaration
+#include "chromeos/ash/services/assistant/public/cpp/assistant_service.h"
 #include "chromeos/services/libassistant/public/mojom/media_controller.mojom-forward.h"
 #include "mojo/public/cpp/bindings/receiver.h"
 #include "mojo/public/cpp/bindings/remote.h"
@@ -17,8 +21,6 @@
 namespace chromeos {
 namespace assistant {
 
-class AssistantBrowserDelegate;
-class AssistantInteractionSubscriber;
 class AssistantManagerServiceImpl;
 class AssistantMediaSession;
 
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.cc b/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.cc
index 3c288a4..5501de8 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.cc
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.cc
@@ -4,8 +4,7 @@
 
 #include "chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 namespace {
 
@@ -29,5 +28,4 @@
   g_instance = nullptr;
 }
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.h b/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.h
index 5a106aa..36735f73 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.h
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_browser_delegate.h
@@ -24,8 +24,7 @@
 #include "chromeos/services/libassistant/public/mojom/service.mojom-forward.h"
 #endif  // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 // Main interface implemented in browser to provide dependencies to
 // |chromeos::assistant::Service|.
@@ -94,7 +93,11 @@
 #endif  // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
 };
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+using ::ash::assistant::AssistantBrowserDelegate;
+}
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_ASSISTANT_BROWSER_DELEGATE_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_enums.h b/chromeos/ash/services/assistant/public/cpp/assistant_enums.h
index 30560f5..b53f834 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_enums.h
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_enums.h
@@ -5,8 +5,7 @@
 #ifndef CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_ASSISTANT_ENUMS_H_
 #define CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_ASSISTANT_ENUMS_H_
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 // The initial state is NOT_READY, after Assistant service started it becomes
 // READY. When Assistant UI shows up the state becomes VISIBLE.
 enum AssistantStatus {
@@ -133,7 +132,15 @@
   kMaxValue = kLoaded,
 };
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+using ::ash::assistant::AssistantAllowedState;
+using ::ash::assistant::AssistantInteractionResolution;
+using ::ash::assistant::AssistantStatus;
+using ::ash::assistant::LibassistantDlcInstallResult;
+using ::ash::assistant::LibassistantDlcLoadStatus;
+}  // namespace chromeos::assistant
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_ASSISTANT_ENUMS_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_prefs.cc b/chromeos/ash/services/assistant/public/cpp/assistant_prefs.cc
index 99eb184..0a85872 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_prefs.cc
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_prefs.cc
@@ -7,9 +7,7 @@
 #include "base/notreached.h"
 #include "components/prefs/pref_registry_simple.h"
 
-namespace chromeos {
-namespace assistant {
-namespace prefs {
+namespace ash::assistant::prefs {
 
 // NOTE: These values are persisted in preferences and cannot be changed.
 const char kAssistantOnboardingModeDefault[] = "Default";
@@ -100,6 +98,4 @@
   return std::string();
 }
 
-}  // namespace prefs
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant::prefs
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_prefs.h b/chromeos/ash/services/assistant/public/cpp/assistant_prefs.h
index eeaaaca..beeac92 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_prefs.h
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_prefs.h
@@ -11,9 +11,7 @@
 
 class PrefRegistrySimple;
 
-namespace chromeos {
-namespace assistant {
-namespace prefs {
+namespace ash::assistant::prefs {
 
 // The status of the user's consent. The enum values cannot be changed because
 // they are persisted on disk.
@@ -80,8 +78,11 @@
 COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC)
 std::string ToOnboardingModeString(AssistantOnboardingMode onboarding_mode);
 
-}  // namespace prefs
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant::prefs
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+namespace prefs = ::ash::assistant::prefs;
+}
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_ASSISTANT_PREFS_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_service.cc b/chromeos/ash/services/assistant/public/cpp/assistant_service.cc
index 412af1c9..8301217 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_service.cc
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_service.cc
@@ -4,8 +4,7 @@
 
 #include "chromeos/ash/services/assistant/public/cpp/assistant_service.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 namespace {
 
@@ -28,5 +27,4 @@
   g_instance = nullptr;
 }
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_service.h b/chromeos/ash/services/assistant/public/cpp/assistant_service.h
index cff50fe..6a5a3e2 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_service.h
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_service.h
@@ -14,6 +14,8 @@
 #include "chromeos/ash/services/assistant/public/cpp/assistant_enums.h"
 #include "chromeos/ash/services/assistant/public/cpp/conversation_observer.h"
 #include "chromeos/services/libassistant/public/cpp/android_app_info.h"
+// TODO(https://crbug.com/1164001): move to forward declaration
+#include "chromeos/services/libassistant/public/cpp/assistant_feedback.h"
 #include "chromeos/services/libassistant/public/cpp/assistant_interaction_metadata.h"
 #include "chromeos/services/libassistant/public/cpp/assistant_notification.h"
 #include "chromeos/services/libassistant/public/mojom/notification_delegate.mojom-forward.h"
@@ -22,10 +24,7 @@
 #include "mojo/public/cpp/bindings/pending_remote.h"
 #include "ui/accessibility/mojom/ax_assistant_structure.mojom.h"
 
-namespace chromeos {
-namespace assistant {
-
-struct AssistantFeedback;
+namespace ash::assistant {
 
 // Subscribes to Assistant's interaction event. These events are server driven
 // in response to the user's direct interaction with the assistant. Responses
@@ -182,7 +181,13 @@
   virtual Assistant* GetAssistant() = 0;
 };
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+using ::ash::assistant::Assistant;
+using ::ash::assistant::AssistantInteractionSubscriber;
+using ::ash::assistant::AssistantService;
+}  // namespace chromeos::assistant
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_ASSISTANT_SERVICE_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_settings.cc b/chromeos/ash/services/assistant/public/cpp/assistant_settings.cc
index eb8ceb8..1121cd3 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_settings.cc
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_settings.cc
@@ -4,8 +4,7 @@
 
 #include "chromeos/ash/services/assistant/public/cpp/assistant_settings.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 namespace {
 
@@ -40,5 +39,4 @@
   g_instance = nullptr;
 }
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
diff --git a/chromeos/ash/services/assistant/public/cpp/assistant_settings.h b/chromeos/ash/services/assistant/public/cpp/assistant_settings.h
index ee329a1..942b0b8f 100644
--- a/chromeos/ash/services/assistant/public/cpp/assistant_settings.h
+++ b/chromeos/ash/services/assistant/public/cpp/assistant_settings.h
@@ -13,8 +13,7 @@
 #include "chromeos/services/libassistant/public/mojom/speaker_id_enrollment_controller.mojom.h"
 #include "mojo/public/cpp/bindings/receiver.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 class COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC) SpeakerIdEnrollmentClient
     : public chromeos::libassistant::mojom::SpeakerIdEnrollmentClient {
@@ -78,7 +77,12 @@
   virtual void SyncSpeakerIdEnrollmentStatus() = 0;
 };
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+using ::ash::assistant::AssistantSettings;
+using ::ash::assistant::SpeakerIdEnrollmentClient;
+}  // namespace chromeos::assistant
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_ASSISTANT_SETTINGS_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/conversation_observer.cc b/chromeos/ash/services/assistant/public/cpp/conversation_observer.cc
index f18971f..8ac2254 100644
--- a/chromeos/ash/services/assistant/public/cpp/conversation_observer.cc
+++ b/chromeos/ash/services/assistant/public/cpp/conversation_observer.cc
@@ -4,8 +4,7 @@
 
 #include "chromeos/ash/services/assistant/public/cpp/conversation_observer.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 ConversationObserver::ConversationObserver() = default;
 ConversationObserver::~ConversationObserver() = default;
@@ -17,5 +16,4 @@
   return remote_observer_.BindNewPipeAndPassRemote();
 }
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
diff --git a/chromeos/ash/services/assistant/public/cpp/conversation_observer.h b/chromeos/ash/services/assistant/public/cpp/conversation_observer.h
index 96cc8137..bb5f5f0 100644
--- a/chromeos/ash/services/assistant/public/cpp/conversation_observer.h
+++ b/chromeos/ash/services/assistant/public/cpp/conversation_observer.h
@@ -11,8 +11,7 @@
 #include "chromeos/services/libassistant/public/mojom/conversation_observer.mojom.h"
 #include "mojo/public/cpp/bindings/receiver.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 // Default implementation of |mojom::ConversationObserver|, which allow child
 // child classes to only implement handlers they are interested in.
@@ -47,7 +46,11 @@
       remote_observer_{this};
 };
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+using ::ash::assistant::ConversationObserver;
+}
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_CONVERSATION_OBSERVER_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/device_actions.cc b/chromeos/ash/services/assistant/public/cpp/device_actions.cc
index eff2d063..1eb79f6f 100644
--- a/chromeos/ash/services/assistant/public/cpp/device_actions.cc
+++ b/chromeos/ash/services/assistant/public/cpp/device_actions.cc
@@ -4,8 +4,7 @@
 
 #include "chromeos/ash/services/assistant/public/cpp/device_actions.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 namespace {
 
@@ -29,5 +28,4 @@
   g_instance = nullptr;
 }
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
diff --git a/chromeos/ash/services/assistant/public/cpp/device_actions.h b/chromeos/ash/services/assistant/public/cpp/device_actions.h
index 6230f27e..ee4bc28 100644
--- a/chromeos/ash/services/assistant/public/cpp/device_actions.h
+++ b/chromeos/ash/services/assistant/public/cpp/device_actions.h
@@ -13,8 +13,7 @@
 #include "base/observer_list_types.h"
 #include "chromeos/ash/services/assistant/public/cpp/assistant_service.h"
 
-namespace chromeos {
-namespace assistant {
+namespace ash::assistant {
 
 // Subscribes to App list events.
 class COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC) AppListEventSubscriber
@@ -78,7 +77,12 @@
       AppListEventSubscriber* subscriber) = 0;
 };
 
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+using ::ash::assistant::AppListEventSubscriber;
+using ::ash::assistant::DeviceActions;
+}  // namespace chromeos::assistant
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_DEVICE_ACTIONS_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/features.cc b/chromeos/ash/services/assistant/public/cpp/features.cc
index 63d37ea1..60006a9 100644
--- a/chromeos/ash/services/assistant/public/cpp/features.cc
+++ b/chromeos/ash/services/assistant/public/cpp/features.cc
@@ -7,9 +7,7 @@
 #include "ash/constants/ash_features.h"
 #include "base/feature_list.h"
 
-namespace chromeos {
-namespace assistant {
-namespace features {
+namespace ash::assistant::features {
 
 const base::Feature kAssistantAudioEraser{"AssistantAudioEraser",
                                           base::FEATURE_DISABLED_BY_DEFAULT};
@@ -99,6 +97,4 @@
   return base::FeatureList::IsEnabled(kEnableLibAssistantV2);
 }
 
-}  // namespace features
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant::features
diff --git a/chromeos/ash/services/assistant/public/cpp/features.h b/chromeos/ash/services/assistant/public/cpp/features.h
index 07de12fa..a170bbc3 100644
--- a/chromeos/ash/services/assistant/public/cpp/features.h
+++ b/chromeos/ash/services/assistant/public/cpp/features.h
@@ -9,9 +9,7 @@
 #include "base/feature_list.h"
 #include "base/metrics/field_trial_params.h"
 
-namespace chromeos {
-namespace assistant {
-namespace features {
+namespace ash::assistant::features {
 
 // Enable Assistant Feedback UI.
 COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC)
@@ -83,8 +81,11 @@
 
 COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC) bool IsLibAssistantV2Enabled();
 
-}  // namespace features
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant::features
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+namespace features = ::ash::assistant::features;
+}
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_FEATURES_H_
diff --git a/chromeos/ash/services/assistant/public/cpp/switches.cc b/chromeos/ash/services/assistant/public/cpp/switches.cc
index 4fd2d11..8285341e 100644
--- a/chromeos/ash/services/assistant/public/cpp/switches.cc
+++ b/chromeos/ash/services/assistant/public/cpp/switches.cc
@@ -4,14 +4,10 @@
 
 #include "chromeos/ash/services/assistant/public/cpp/switches.h"
 
-namespace chromeos {
-namespace assistant {
-namespace switches {
+namespace ash::assistant::switches {
 
 const char kForceAssistantOnboarding[] = "force-assistant-onboarding";
 const char kRedirectLibassistantLogging[] = "redirect-libassistant-logging";
 const char kDisableLibAssistantLogfile[] = "disable-libassistant-logfile";
 
-}  // namespace switches
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant::switches
diff --git a/chromeos/ash/services/assistant/public/cpp/switches.h b/chromeos/ash/services/assistant/public/cpp/switches.h
index 3cae5fe88..f3ea9fa 100644
--- a/chromeos/ash/services/assistant/public/cpp/switches.h
+++ b/chromeos/ash/services/assistant/public/cpp/switches.h
@@ -7,9 +7,7 @@
 
 #include "base/component_export.h"
 
-namespace chromeos {
-namespace assistant {
-namespace switches {
+namespace ash::assistant::switches {
 
 // NOTE: Switches are reserved for developer-facing options. End-user facing
 // features should use base::Feature. See features.h.
@@ -29,8 +27,11 @@
 COMPONENT_EXPORT(ASSISTANT_SERVICE_PUBLIC)
 extern const char kDisableLibAssistantLogfile[];
 
-}  // namespace switches
-}  // namespace assistant
-}  // namespace chromeos
+}  // namespace ash::assistant::switches
+
+// TODO(https://crbug.com/1164001): remove when the migration is finished.
+namespace chromeos::assistant {
+namespace switches = ::ash::assistant::switches;
+}
 
 #endif  // CHROMEOS_ASH_SERVICES_ASSISTANT_PUBLIC_CPP_SWITCHES_H_
diff --git a/chromeos/ash/services/assistant/service_context.h b/chromeos/ash/services/assistant/service_context.h
index 31dba51..1717db5 100644
--- a/chromeos/ash/services/assistant/service_context.h
+++ b/chromeos/ash/services/assistant/service_context.h
@@ -12,6 +12,8 @@
 // ash/.
 #include "ash/components/audio/cras_audio_handler.h"
 #include "base/memory/scoped_refptr.h"
+// TODO(https://crbug.com/1164001): move to forward declaration
+#include "chromeos/ash/services/assistant/public/cpp/device_actions.h"
 
 namespace ash {
 class AssistantAlarmTimerController;
@@ -31,8 +33,6 @@
 namespace chromeos {
 namespace assistant {
 
-class DeviceActions;
-
 // Context object passed around so classes can access some of the |Service|
 // functionality without directly depending on the |Service| class.
 class ServiceContext {
diff --git a/chromeos/services/libassistant/public/cpp/android_app_info.h b/chromeos/services/libassistant/public/cpp/android_app_info.h
index a8bda075..832979e 100644
--- a/chromeos/services/libassistant/public/cpp/android_app_info.h
+++ b/chromeos/services/libassistant/public/cpp/android_app_info.h
@@ -52,4 +52,10 @@
 }  // namespace assistant
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove when it moved to ash.
+namespace ash::assistant {
+using ::chromeos::assistant::AndroidAppInfo;
+using ::chromeos::assistant::AppStatus;
+}  // namespace ash::assistant
+
 #endif  // CHROMEOS_SERVICES_LIBASSISTANT_PUBLIC_CPP_ANDROID_APP_INFO_H_
diff --git a/chromeos/services/libassistant/public/cpp/assistant_feedback.h b/chromeos/services/libassistant/public/cpp/assistant_feedback.h
index 9e4dce9..de55a7d 100644
--- a/chromeos/services/libassistant/public/cpp/assistant_feedback.h
+++ b/chromeos/services/libassistant/public/cpp/assistant_feedback.h
@@ -33,4 +33,9 @@
 }  // namespace assistant
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove when it moved to ash.
+namespace ash::assistant {
+using ::chromeos::assistant::AssistantFeedback;
+}
+
 #endif  // CHROMEOS_SERVICES_LIBASSISTANT_PUBLIC_CPP_ASSISTANT_FEEDBACK_H_
diff --git a/chromeos/services/libassistant/public/cpp/assistant_interaction_metadata.h b/chromeos/services/libassistant/public/cpp/assistant_interaction_metadata.h
index 23719b3..fadb32ae 100644
--- a/chromeos/services/libassistant/public/cpp/assistant_interaction_metadata.h
+++ b/chromeos/services/libassistant/public/cpp/assistant_interaction_metadata.h
@@ -62,4 +62,9 @@
 }  // namespace assistant
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove when it moved to ash.
+namespace ash::assistant {
+using ::chromeos::assistant::AssistantQuerySource;
+}
+
 #endif  // CHROMEOS_SERVICES_LIBASSISTANT_PUBLIC_CPP_ASSISTANT_INTERACTION_METADATA_H_
diff --git a/chromeos/services/libassistant/public/cpp/assistant_notification.h b/chromeos/services/libassistant/public/cpp/assistant_notification.h
index 188c2da..53a92d5 100644
--- a/chromeos/services/libassistant/public/cpp/assistant_notification.h
+++ b/chromeos/services/libassistant/public/cpp/assistant_notification.h
@@ -104,4 +104,9 @@
 }  // namespace assistant
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove when it moved to ash.
+namespace ash::assistant {
+using ::chromeos::assistant::AssistantNotification;
+}
+
 #endif  // CHROMEOS_SERVICES_LIBASSISTANT_PUBLIC_CPP_ASSISTANT_NOTIFICATION_H_
diff --git a/chromeos/services/libassistant/public/cpp/assistant_suggestion.h b/chromeos/services/libassistant/public/cpp/assistant_suggestion.h
index 47a0ea28..0a59b63f 100644
--- a/chromeos/services/libassistant/public/cpp/assistant_suggestion.h
+++ b/chromeos/services/libassistant/public/cpp/assistant_suggestion.h
@@ -73,4 +73,9 @@
 }  // namespace assistant
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove when it moved to ash.
+namespace ash::assistant {
+using ::chromeos::assistant::AssistantSuggestion;
+}
+
 #endif  // CHROMEOS_SERVICES_LIBASSISTANT_PUBLIC_CPP_ASSISTANT_SUGGESTION_H_
diff --git a/docs/login/first_user_run_oobe.md b/docs/login/first_user_run_oobe.md
index 9a41f051..3517613 100644
--- a/docs/login/first_user_run_oobe.md
+++ b/docs/login/first_user_run_oobe.md
@@ -94,7 +94,7 @@
 The final step of the opt-in flow is informing the user the Assistant is ready,
 and offering to enable some advanced features, if any are available.
 
-Much of this flow is managed by chromeos::assistant::AssistantSettings service.
+Much of this flow is managed by ash::assistant::AssistantSettings service.
 To effectively test the screen flow, this service should be faked by the test.
 
 # Multi-device Setup screen