Migrate ash/services/secure_channel/ to ns ash (2/n)

This CL migrates ash/services/secure_channel/ble_*.

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

Bug: 1164001
Change-Id: I3c4091bf2df2f3c5a17a5130230ddd9190734561
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3460871
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Owners-Override: Hidehiko Abe <hidehiko@chromium.org>
Commit-Queue: Henrique Ferreiro <hferreiro@igalia.com>
Cr-Commit-Position: refs/heads/main@{#971779}
diff --git a/ash/services/secure_channel/ble_advertisement_generator.cc b/ash/services/secure_channel/ble_advertisement_generator.cc
index 60986ee..b76f5ac 100644
--- a/ash/services/secure_channel/ble_advertisement_generator.cc
+++ b/ash/services/secure_channel/ble_advertisement_generator.cc
@@ -10,9 +10,7 @@
 #include "chromeos/components/multidevice/logging/logging.h"
 #include "chromeos/components/multidevice/remote_device_ref.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // static
 BleAdvertisementGenerator* BleAdvertisementGenerator::instance_ = nullptr;
@@ -76,6 +74,4 @@
   eid_generator_ = std::move(test_eid_generator);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_advertisement_generator.h b/ash/services/secure_channel/ble_advertisement_generator.h
index ea99718..47e1c5cb 100644
--- a/ash/services/secure_channel/ble_advertisement_generator.h
+++ b/ash/services/secure_channel/ble_advertisement_generator.h
@@ -8,14 +8,16 @@
 #include <memory>
 
 #include "ash/services/secure_channel/foreground_eid_generator.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "chromeos/components/multidevice/remote_device_ref.h"
 
 namespace chromeos {
-
-namespace multidevice {
-class RemoteDeviceRef;
-}  // namespace multidevice
-
 namespace secure_channel {
+class SecureChannelBluetoothHelperImplTest;
+}
+}  // namespace chromeos
+
+namespace ash::secure_channel {
 
 // Generates advertisements for the ProximityAuth BLE advertisement scheme.
 class BleAdvertisementGenerator {
@@ -42,7 +44,7 @@
 
  private:
   friend class SecureChannelBleAdvertisementGeneratorTest;
-  friend class SecureChannelBluetoothHelperImplTest;
+  friend class chromeos::secure_channel::SecureChannelBluetoothHelperImplTest;
 
   static BleAdvertisementGenerator* instance_;
 
@@ -55,8 +57,11 @@
   std::unique_ptr<ForegroundEidGenerator> eid_generator_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleAdvertisementGenerator;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_ADVERTISEMENT_GENERATOR_H_
diff --git a/ash/services/secure_channel/ble_advertisement_generator_unittest.cc b/ash/services/secure_channel/ble_advertisement_generator_unittest.cc
index 773bbcf..a806023 100644
--- a/ash/services/secure_channel/ble_advertisement_generator_unittest.cc
+++ b/ash/services/secure_channel/ble_advertisement_generator_unittest.cc
@@ -15,11 +15,7 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using testing::StrictMock;
-
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
@@ -109,6 +105,4 @@
                                           kLocalDevicePublicKey));
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_advertiser.cc b/ash/services/secure_channel/ble_advertiser.cc
index 6ad2267..beaca03 100644
--- a/ash/services/secure_channel/ble_advertiser.cc
+++ b/ash/services/secure_channel/ble_advertiser.cc
@@ -4,9 +4,7 @@
 
 #include "ash/services/secure_channel/ble_advertiser.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 BleAdvertiser::BleAdvertiser(Delegate* delegate) : delegate_(delegate) {}
 
@@ -24,6 +22,4 @@
   delegate_->OnFailureToGenerateAdvertisement(device_id_pair);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_advertiser.h b/ash/services/secure_channel/ble_advertiser.h
index a4bf7f46..f57c7e4 100644
--- a/ash/services/secure_channel/ble_advertiser.h
+++ b/ash/services/secure_channel/ble_advertiser.h
@@ -9,9 +9,7 @@
 #include "ash/services/secure_channel/device_id_pair.h"
 #include "ash/services/secure_channel/public/cpp/shared/connection_priority.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // Registers BLE advertisements targeted to remote devices.
 class BleAdvertiser {
@@ -71,8 +69,11 @@
   Delegate* delegate_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleAdvertiser;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_ADVERTISER_H_
diff --git a/ash/services/secure_channel/ble_advertiser_impl.cc b/ash/services/secure_channel/ble_advertiser_impl.cc
index f26d294..50a3cfbc 100644
--- a/ash/services/secure_channel/ble_advertiser_impl.cc
+++ b/ash/services/secure_channel/ble_advertiser_impl.cc
@@ -16,9 +16,7 @@
 #include "base/timer/timer.h"
 #include "chromeos/components/multidevice/logging/logging.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 BleAdvertiserImpl::ActiveAdvertisementRequest::ActiveAdvertisementRequest(
     DeviceIdPair device_id_pair,
@@ -386,6 +384,4 @@
   NotifyFailureToGenerateAdvertisement(device_id_pair);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_advertiser_impl.h b/ash/services/secure_channel/ble_advertiser_impl.h
index 2effbe5a8..be10015 100644
--- a/ash/services/secure_channel/ble_advertiser_impl.h
+++ b/ash/services/secure_channel/ble_advertiser_impl.h
@@ -11,8 +11,18 @@
 
 #include "ash/services/secure_channel/ble_advertiser.h"
 #include "ash/services/secure_channel/ble_constants.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_synchronizer_base.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/bluetooth_helper.h"
 #include "ash/services/secure_channel/device_id_pair.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/error_tolerant_ble_advertisement.h"
 #include "ash/services/secure_channel/public/cpp/shared/connection_priority.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/shared_resource_scheduler.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/timer_factory.h"
 #include "base/containers/flat_set.h"
 #include "base/memory/weak_ptr.h"
 #include "base/task/sequenced_task_runner.h"
@@ -21,17 +31,9 @@
 
 namespace base {
 class OneShotTimer;
-}  // namespace base
+}
 
-namespace chromeos {
-
-namespace secure_channel {
-
-class BluetoothHelper;
-class BleSynchronizerBase;
-class ErrorTolerantBleAdvertisement;
-class SharedResourceScheduler;
-class TimerFactory;
+namespace ash::secure_channel {
 
 // Concrete BleAdvertiser implementation. Because systems have a limited number
 // of BLE advertisement slots, this class limits the number of concurrent
@@ -172,8 +174,11 @@
   base::WeakPtrFactory<BleAdvertiserImpl> weak_factory_{this};
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleAdvertiserImpl;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_ADVERTISER_IMPL_H_
diff --git a/ash/services/secure_channel/ble_advertiser_impl_unittest.cc b/ash/services/secure_channel/ble_advertiser_impl_unittest.cc
index 1d21208..403c06b 100644
--- a/ash/services/secure_channel/ble_advertiser_impl_unittest.cc
+++ b/ash/services/secure_channel/ble_advertiser_impl_unittest.cc
@@ -21,9 +21,7 @@
 #include "base/test/test_simple_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
@@ -748,6 +746,4 @@
   EXPECT_EQ(0u, GetNumFailedAdvertisementDelegateCallbacks());
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_characteristics_finder.cc b/ash/services/secure_channel/ble_characteristics_finder.cc
index 8ba6d20..b0f26b0 100644
--- a/ash/services/secure_channel/ble_characteristics_finder.cc
+++ b/ash/services/secure_channel/ble_characteristics_finder.cc
@@ -13,21 +13,21 @@
 #include "device/bluetooth/bluetooth_remote_gatt_characteristic.h"
 #include "device/bluetooth/public/cpp/bluetooth_uuid.h"
 
-using device::BluetoothAdapter;
-using device::BluetoothDevice;
-using device::BluetoothRemoteGattCharacteristic;
-using device::BluetoothRemoteGattService;
-using device::BluetoothUUID;
+namespace ash::secure_channel {
+
+using ::device::BluetoothAdapter;
+using ::device::BluetoothDevice;
+using ::device::BluetoothRemoteGattCharacteristic;
+using ::device::BluetoothRemoteGattService;
+using ::device::BluetoothUUID;
 
 namespace {
+
 // The UUID of the characteristic for eid verification.
 const char kEidCharacteristicUuid[] = "f21843b0-9411-434b-b85f-a9b92bd69f77";
+
 }  // namespace
 
-namespace chromeos {
-
-namespace secure_channel {
-
 BluetoothLowEnergyCharacteristicsFinder::
     BluetoothLowEnergyCharacteristicsFinder(
         scoped_refptr<BluetoothAdapter> adapter,
@@ -235,6 +235,4 @@
   return !identified_device_id.empty();
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_characteristics_finder.h b/ash/services/secure_channel/ble_characteristics_finder.h
index e84a140c..cc6fdf2 100644
--- a/ash/services/secure_channel/ble_characteristics_finder.h
+++ b/ash/services/secure_channel/ble_characteristics_finder.h
@@ -5,8 +5,6 @@
 #ifndef ASH_SERVICES_SECURE_CHANNEL_BLE_CHARACTERISTICS_FINDER_H_
 #define ASH_SERVICES_SECURE_CHANNEL_BLE_CHARACTERISTICS_FINDER_H_
 
-// TODO(https://crbug.com/1164001): move to forward declaration.
-#include "ash/services/secure_channel/background_eid_generator.h"
 #include "ash/services/secure_channel/remote_attribute.h"
 #include "base/callback.h"
 #include "base/containers/flat_set.h"
@@ -20,9 +18,9 @@
 #include "device/bluetooth/bluetooth_remote_gatt_service.h"
 #include "device/bluetooth/public/cpp/bluetooth_uuid.h"
 
-namespace chromeos {
+namespace ash::secure_channel {
 
-namespace secure_channel {
+class BackgroundEidGenerator;
 
 // Looks for given characteristics in a remote device, for which a GATT
 // connection was already established. In the current BLE connection protocol
@@ -146,8 +144,11 @@
       weak_ptr_factory_{this};
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BluetoothLowEnergyCharacteristicsFinder;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_CHARACTERISTICS_FINDER_H_
diff --git a/ash/services/secure_channel/ble_characteristics_finder_unittest.cc b/ash/services/secure_channel/ble_characteristics_finder_unittest.cc
index 8e6158ac..c16a733 100644
--- a/ash/services/secure_channel/ble_characteristics_finder_unittest.cc
+++ b/ash/services/secure_channel/ble_characteristics_finder_unittest.cc
@@ -25,31 +25,29 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using device::BluetoothAdapter;
-using device::BluetoothAdapterFactory;
-using device::BluetoothDevice;
-using device::BluetoothGattService;
-using device::BluetoothRemoteGattCharacteristic;
-using device::BluetoothRemoteGattService;
-using device::BluetoothUUID;
-using device::MockBluetoothAdapter;
-using device::MockBluetoothDevice;
-using device::MockBluetoothGattCharacteristic;
-using device::MockBluetoothGattService;
-using testing::_;
-using testing::AtLeast;
-using testing::DoAll;
-using testing::Invoke;
-using testing::NiceMock;
-using testing::Return;
-using testing::SaveArg;
-using testing::StrictMock;
+namespace ash::secure_channel {
 
-namespace chromeos {
-
-namespace secure_channel {
 namespace {
 
+using ::device::BluetoothAdapter;
+using ::device::BluetoothAdapterFactory;
+using ::device::BluetoothDevice;
+using ::device::BluetoothGattService;
+using ::device::BluetoothRemoteGattCharacteristic;
+using ::device::BluetoothRemoteGattService;
+using ::device::BluetoothUUID;
+using ::device::MockBluetoothAdapter;
+using ::device::MockBluetoothDevice;
+using ::device::MockBluetoothGattCharacteristic;
+using ::device::MockBluetoothGattService;
+using ::testing::_;
+using ::testing::AtLeast;
+using ::testing::DoAll;
+using ::testing::Invoke;
+using ::testing::NiceMock;
+using ::testing::Return;
+using ::testing::SaveArg;
+
 const char kDeviceName[] = "Device name";
 const char kBluetoothAddress[] = "11:22:33:44:55:66";
 
@@ -597,6 +595,4 @@
   EXPECT_EQ(kFromPeripheralCharID, found_from_char.id);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_connection_manager.cc b/ash/services/secure_channel/ble_connection_manager.cc
index 03523b5..98b57d99 100644
--- a/ash/services/secure_channel/ble_connection_manager.cc
+++ b/ash/services/secure_channel/ble_connection_manager.cc
@@ -10,9 +10,7 @@
 #include "chromeos/components/multidevice/logging/logging.h"
 #include "chromeos/components/multidevice/remote_device_ref.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 BleConnectionManager::InitiatorConnectionAttemptMetadata::
     InitiatorConnectionAttemptMetadata(
@@ -324,6 +322,4 @@
   }
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_connection_manager.h b/ash/services/secure_channel/ble_connection_manager.h
index c60af881..84bee23 100644
--- a/ash/services/secure_channel/ble_connection_manager.h
+++ b/ash/services/secure_channel/ble_connection_manager.h
@@ -7,11 +7,10 @@
 
 #include <memory>
 
-// TODO(https://crbug.com/1164001): move to forward declaration.
-#include "ash/services/secure_channel/authenticated_channel.h"
 #include "ash/services/secure_channel/ble_initiator_failure_type.h"
 #include "ash/services/secure_channel/ble_listener_failure_type.h"
 #include "ash/services/secure_channel/connection_attempt_details.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
 #include "ash/services/secure_channel/connection_role.h"
 #include "ash/services/secure_channel/device_id_pair.h"
 #include "ash/services/secure_channel/public/cpp/shared/connection_priority.h"
@@ -19,9 +18,9 @@
 #include "base/containers/flat_map.h"
 #include "base/containers/flat_set.h"
 
-namespace chromeos {
+namespace ash::secure_channel {
 
-namespace secure_channel {
+class AuthenticatedChannel;
 
 // Creates connections to remote devices over Bluetooth, using either the
 // listener role (BLE scans only) or the initiator role (a combination of BLE
@@ -151,8 +150,11 @@
       id_pair_to_listener_metadata_map_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleConnectionManager;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_CONNECTION_MANAGER_H_
diff --git a/ash/services/secure_channel/ble_connection_manager_impl.cc b/ash/services/secure_channel/ble_connection_manager_impl.cc
index 2c896d1..a151028 100644
--- a/ash/services/secure_channel/ble_connection_manager_impl.cc
+++ b/ash/services/secure_channel/ble_connection_manager_impl.cc
@@ -22,12 +22,13 @@
 #include "chromeos/components/multidevice/logging/logging.h"
 #include "device/bluetooth/public/cpp/bluetooth_uuid.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace mojom = ::chromeos::secure_channel::mojom;
+
 std::vector<mojom::ConnectionCreationDetail> CreateConnectionDetails(
     ConnectionRole connection_role) {
   std::vector<mojom::ConnectionCreationDetail> creation_details;
@@ -647,6 +648,4 @@
   remote_device_id_to_timestamps_map_.erase(remote_device_id);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_connection_manager_impl.h b/ash/services/secure_channel/ble_connection_manager_impl.h
index e30c1baa..c079a41f9 100644
--- a/ash/services/secure_channel/ble_connection_manager_impl.h
+++ b/ash/services/secure_channel/ble_connection_manager_impl.h
@@ -11,26 +11,27 @@
 #include "ash/services/secure_channel/ble_advertiser.h"
 #include "ash/services/secure_channel/ble_connection_manager.h"
 #include "ash/services/secure_channel/ble_scanner.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_synchronizer_base.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/bluetooth_helper.h"
 #include "ash/services/secure_channel/connection_role.h"
 #include "ash/services/secure_channel/device_id_pair.h"
 #include "ash/services/secure_channel/public/cpp/shared/connection_priority.h"
 #include "ash/services/secure_channel/secure_channel.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/secure_channel_disconnector.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/timer_factory.h"
 #include "base/containers/flat_map.h"
 #include "base/memory/ref_counted.h"
 #include "base/time/default_clock.h"
 
 namespace device {
 class BluetoothAdapter;
-}  // namespace device
+}
 
-namespace chromeos {
-
-namespace secure_channel {
-
-class BluetoothHelper;
-class BleSynchronizerBase;
-class SecureChannelDisconnector;
-class TimerFactory;
+namespace ash::secure_channel {
 
 // Concrete BleConnectionManager implementation. This class initializes
 // BleAdvertiser and BleScanner objects and utilizes them to bootstrap
@@ -223,8 +224,11 @@
   absl::optional<std::string> notifying_remote_device_id_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleConnectionManagerImpl;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_CONNECTION_MANAGER_IMPL_H_
diff --git a/ash/services/secure_channel/ble_connection_manager_impl_unittest.cc b/ash/services/secure_channel/ble_connection_manager_impl_unittest.cc
index c4e6f118..3992183 100644
--- a/ash/services/secure_channel/ble_connection_manager_impl_unittest.cc
+++ b/ash/services/secure_channel/ble_connection_manager_impl_unittest.cc
@@ -37,12 +37,13 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace mojom = ::chromeos::secure_channel::mojom;
+
 const size_t kNumTestDevices = 5;
 
 constexpr base::TimeDelta kScanToAdvertisementTime = base::Seconds(3);
@@ -1331,6 +1332,4 @@
       true, 1u /* expected_count */);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_constants.h b/ash/services/secure_channel/ble_constants.h
index df03ea1..ae23f8c 100644
--- a/ash/services/secure_channel/ble_constants.h
+++ b/ash/services/secure_channel/ble_constants.h
@@ -5,9 +5,7 @@
 #ifndef ASH_SERVICES_SECURE_CHANNEL_BLE_CONSTANTS_H_
 #define ASH_SERVICES_SECURE_CHANNEL_BLE_CONSTANTS_H_
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // The maximum number of devices to which to advertise concurrently. If more
 // than this number of devices are registered, other advertisements must be
@@ -25,8 +23,11 @@
 // The GATT server UUID used for uWeave.
 constexpr const char kGattServerUuid[] = "b3b7e28e-a000-3e17-bd86-6e97b9e28c11";
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+//// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::kAdvertisingServiceUuid;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_CONSTANTS_H_
diff --git a/ash/services/secure_channel/ble_initiator_connection_attempt.cc b/ash/services/secure_channel/ble_initiator_connection_attempt.cc
index 79dfb08..dbeebe9 100644
--- a/ash/services/secure_channel/ble_initiator_connection_attempt.cc
+++ b/ash/services/secure_channel/ble_initiator_connection_attempt.cc
@@ -7,9 +7,7 @@
 #include "ash/services/secure_channel/ble_initiator_operation.h"
 #include "base/memory/ptr_util.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // static
 BleInitiatorConnectionAttempt::Factory*
@@ -62,6 +60,4 @@
       device_id_pair, connection_priority);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_initiator_connection_attempt.h b/ash/services/secure_channel/ble_initiator_connection_attempt.h
index f75a0486..adc0f7e 100644
--- a/ash/services/secure_channel/ble_initiator_connection_attempt.h
+++ b/ash/services/secure_channel/ble_initiator_connection_attempt.h
@@ -10,9 +10,7 @@
 #include "ash/services/secure_channel/ble_initiator_failure_type.h"
 #include "ash/services/secure_channel/connection_attempt_base.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 class BleConnectionManager;
 
@@ -64,8 +62,11 @@
   BleConnectionManager* ble_connection_manager_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleInitiatorConnectionAttempt;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_INITIATOR_CONNECTION_ATTEMPT_H_
diff --git a/ash/services/secure_channel/ble_initiator_failure_type.cc b/ash/services/secure_channel/ble_initiator_failure_type.cc
index 42c5da5..d6ec47d 100644
--- a/ash/services/secure_channel/ble_initiator_failure_type.cc
+++ b/ash/services/secure_channel/ble_initiator_failure_type.cc
@@ -4,9 +4,7 @@
 
 #include "ash/services/secure_channel/ble_initiator_failure_type.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 std::ostream& operator<<(std::ostream& stream,
                          const BleInitiatorFailureType& failure_type) {
@@ -30,6 +28,4 @@
   return stream;
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_initiator_failure_type.h b/ash/services/secure_channel/ble_initiator_failure_type.h
index 8b22bb641..4b85a6e6 100644
--- a/ash/services/secure_channel/ble_initiator_failure_type.h
+++ b/ash/services/secure_channel/ble_initiator_failure_type.h
@@ -7,9 +7,7 @@
 
 #include <ostream>
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 enum class BleInitiatorFailureType {
   // A connection was formed successfully, but there was an error
@@ -34,8 +32,11 @@
 std::ostream& operator<<(std::ostream& stream,
                          const BleInitiatorFailureType& failure_type);
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleInitiatorFailureType;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_INITIATOR_FAILURE_TYPE_H_
diff --git a/ash/services/secure_channel/ble_initiator_operation.cc b/ash/services/secure_channel/ble_initiator_operation.cc
index afb92eb..6d649f3 100644
--- a/ash/services/secure_channel/ble_initiator_operation.cc
+++ b/ash/services/secure_channel/ble_initiator_operation.cc
@@ -9,9 +9,7 @@
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // static
 BleInitiatorOperation::Factory* BleInitiatorOperation::Factory::test_factory_ =
@@ -102,6 +100,4 @@
   OnFailedConnectionAttempt(failure_type);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_initiator_operation.h b/ash/services/secure_channel/ble_initiator_operation.h
index f9e9682..77828d3 100644
--- a/ash/services/secure_channel/ble_initiator_operation.h
+++ b/ash/services/secure_channel/ble_initiator_operation.h
@@ -7,17 +7,15 @@
 
 #include <memory>
 
-// TODO(https://crbug.com/1164001): move to forward declaration.
 #include "ash/services/secure_channel/ble_initiator_failure_type.h"
 #include "ash/services/secure_channel/connect_to_device_operation.h"
 #include "ash/services/secure_channel/connect_to_device_operation_base.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
 #include "ash/services/secure_channel/public/cpp/shared/connection_priority.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_task_runner_handle.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 class BleConnectionManager;
 
@@ -88,8 +86,6 @@
   base::WeakPtrFactory<BleInitiatorOperation> weak_ptr_factory_{this};
 };
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_INITIATOR_OPERATION_H_
diff --git a/ash/services/secure_channel/ble_initiator_operation_unittest.cc b/ash/services/secure_channel/ble_initiator_operation_unittest.cc
index dc3e82b5..9673755 100644
--- a/ash/services/secure_channel/ble_initiator_operation_unittest.cc
+++ b/ash/services/secure_channel/ble_initiator_operation_unittest.cc
@@ -16,9 +16,7 @@
 #include "base/test/test_simple_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 const char kTestRemoteDeviceId[] = "testRemoteDeviceId";
 const char kTestLocalDeviceId[] = "testLocalDeviceId";
@@ -149,6 +147,4 @@
   CompleteAttemptSuccessfully();
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_listener_connection_attempt.cc b/ash/services/secure_channel/ble_listener_connection_attempt.cc
index 2fe8640..63e06b1 100644
--- a/ash/services/secure_channel/ble_listener_connection_attempt.cc
+++ b/ash/services/secure_channel/ble_listener_connection_attempt.cc
@@ -8,9 +8,7 @@
 #include "ash/services/secure_channel/connection_metrics_logger.h"
 #include "base/memory/ptr_util.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // static
 BleListenerConnectionAttempt::Factory*
@@ -70,6 +68,4 @@
       duration);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_listener_connection_attempt.h b/ash/services/secure_channel/ble_listener_connection_attempt.h
index 903f4d2..3a93213 100644
--- a/ash/services/secure_channel/ble_listener_connection_attempt.h
+++ b/ash/services/secure_channel/ble_listener_connection_attempt.h
@@ -10,9 +10,7 @@
 #include "ash/services/secure_channel/ble_listener_failure_type.h"
 #include "ash/services/secure_channel/connection_attempt_base.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 class BleConnectionManager;
 
@@ -69,8 +67,11 @@
   BleConnectionManager* ble_connection_manager_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleListenerConnectionAttempt;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_LISTENER_CONNECTION_ATTEMPT_H_
diff --git a/ash/services/secure_channel/ble_listener_failure_type.cc b/ash/services/secure_channel/ble_listener_failure_type.cc
index cd4fcbd..23fe9711 100644
--- a/ash/services/secure_channel/ble_listener_failure_type.cc
+++ b/ash/services/secure_channel/ble_listener_failure_type.cc
@@ -6,9 +6,7 @@
 
 #include "base/check_op.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 std::ostream& operator<<(std::ostream& stream,
                          const BleListenerFailureType& failure_type) {
@@ -17,6 +15,4 @@
   return stream;
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_listener_failure_type.h b/ash/services/secure_channel/ble_listener_failure_type.h
index 0396b33..8bf89e7 100644
--- a/ash/services/secure_channel/ble_listener_failure_type.h
+++ b/ash/services/secure_channel/ble_listener_failure_type.h
@@ -7,9 +7,7 @@
 
 #include <ostream>
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 enum class BleListenerFailureType {
   // A connection was formed successfully, but there was an error
@@ -20,8 +18,11 @@
 std::ostream& operator<<(std::ostream& stream,
                          const BleListenerFailureType& failure_type);
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleListenerFailureType;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_LISTENER_FAILURE_TYPE_H_
diff --git a/ash/services/secure_channel/ble_listener_operation.cc b/ash/services/secure_channel/ble_listener_operation.cc
index 4bea611..61aad59 100644
--- a/ash/services/secure_channel/ble_listener_operation.cc
+++ b/ash/services/secure_channel/ble_listener_operation.cc
@@ -9,9 +9,7 @@
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // static
 BleListenerOperation::Factory* BleListenerOperation::Factory::test_factory_ =
@@ -101,6 +99,4 @@
   OnFailedConnectionAttempt(failure_type);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_listener_operation.h b/ash/services/secure_channel/ble_listener_operation.h
index de83b66..62c6112 100644
--- a/ash/services/secure_channel/ble_listener_operation.h
+++ b/ash/services/secure_channel/ble_listener_operation.h
@@ -7,7 +7,6 @@
 
 #include <memory>
 
-// TODO(https://crbug.com/1164001): move to forward declaration.
 #include "ash/services/secure_channel/ble_listener_failure_type.h"
 #include "ash/services/secure_channel/connect_to_device_operation.h"
 #include "ash/services/secure_channel/connect_to_device_operation_base.h"
@@ -15,9 +14,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_task_runner_handle.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 class BleConnectionManager;
 
@@ -90,8 +87,6 @@
   base::WeakPtrFactory<BleListenerOperation> weak_ptr_factory_{this};
 };
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_LISTENER_OPERATION_H_
diff --git a/ash/services/secure_channel/ble_listener_operation_unittest.cc b/ash/services/secure_channel/ble_listener_operation_unittest.cc
index 1fb6e56..f96c9d6 100644
--- a/ash/services/secure_channel/ble_listener_operation_unittest.cc
+++ b/ash/services/secure_channel/ble_listener_operation_unittest.cc
@@ -16,9 +16,7 @@
 #include "base/test/test_simple_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 const char kTestRemoteDeviceId[] = "testRemoteDeviceId";
 const char kTestLocalDeviceId[] = "testLocalDeviceId";
@@ -144,6 +142,4 @@
   CompleteAttemptSuccessfully();
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_scanner.cc b/ash/services/secure_channel/ble_scanner.cc
index 01a91e56..71ea2f9 100644
--- a/ash/services/secure_channel/ble_scanner.cc
+++ b/ash/services/secure_channel/ble_scanner.cc
@@ -9,9 +9,7 @@
 #include "base/notreached.h"
 #include "chromeos/components/multidevice/logging/logging.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 BleScanner::BleScanner() = default;
 
@@ -71,6 +69,4 @@
   }
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_scanner.h b/ash/services/secure_channel/ble_scanner.h
index 3ee68d8..5f65bc6 100644
--- a/ash/services/secure_channel/ble_scanner.h
+++ b/ash/services/secure_channel/ble_scanner.h
@@ -18,11 +18,9 @@
 
 namespace device {
 class BluetoothDevice;
-}  // namespace device
+}
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // Performs BLE scans and notifies its delegate when an advertisement has been
 // received from a remote device. This class allows clients to specify what type
@@ -84,8 +82,11 @@
   base::flat_set<ConnectionAttemptDetails> scan_requests_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleScanner;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_SCANNER_H_
diff --git a/ash/services/secure_channel/ble_scanner_impl.cc b/ash/services/secure_channel/ble_scanner_impl.cc
index e7480704..1dde8acc 100644
--- a/ash/services/secure_channel/ble_scanner_impl.cc
+++ b/ash/services/secure_channel/ble_scanner_impl.cc
@@ -21,9 +21,7 @@
 #include "device/bluetooth/bluetooth_discovery_session.h"
 #include "device/bluetooth/public/cpp/bluetooth_uuid.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
@@ -304,6 +302,4 @@
   service_data_provider_ = std::move(service_data_provider);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_scanner_impl.h b/ash/services/secure_channel/ble_scanner_impl.h
index 8431970..17bc923 100644
--- a/ash/services/secure_channel/ble_scanner_impl.h
+++ b/ash/services/secure_channel/ble_scanner_impl.h
@@ -19,11 +19,8 @@
 class BluetoothDiscoverySession;
 }  // namespace device
 
-namespace chromeos {
+namespace ash::secure_channel {
 
-namespace secure_channel {
-
-class BluetoothHelper;
 class BleSynchronizerBase;
 
 // Concrete BleScanner implementation.
@@ -118,8 +115,11 @@
   base::WeakPtrFactory<BleScannerImpl> weak_ptr_factory_{this};
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleScannerImpl;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_SCANNER_IMPL_H_
diff --git a/ash/services/secure_channel/ble_scanner_impl_unittest.cc b/ash/services/secure_channel/ble_scanner_impl_unittest.cc
index 3fe9381..2ca499a5 100644
--- a/ash/services/secure_channel/ble_scanner_impl_unittest.cc
+++ b/ash/services/secure_channel/ble_scanner_impl_unittest.cc
@@ -23,9 +23,7 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
@@ -515,6 +513,4 @@
   EXPECT_EQ(1u, GetNumBleCommands());
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_synchronizer.cc b/ash/services/secure_channel/ble_synchronizer.cc
index 69e1a0b..eee4a16a 100644
--- a/ash/services/secure_channel/ble_synchronizer.cc
+++ b/ash/services/secure_channel/ble_synchronizer.cc
@@ -13,9 +13,7 @@
 #include "base/time/default_clock.h"
 #include "chromeos/components/multidevice/logging/logging.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
@@ -312,6 +310,4 @@
                         success);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_synchronizer.h b/ash/services/secure_channel/ble_synchronizer.h
index ac95b35..6295b99 100644
--- a/ash/services/secure_channel/ble_synchronizer.h
+++ b/ash/services/secure_channel/ble_synchronizer.h
@@ -19,11 +19,9 @@
 
 namespace base {
 class TaskRunner;
-}  // namespace base
+}
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // Concrete BleSynchronizerBase implementation.
 class BleSynchronizer : public BleSynchronizerBase {
@@ -110,8 +108,11 @@
   base::WeakPtrFactory<BleSynchronizer> weak_ptr_factory_{this};
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleSynchronizer;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_SYNCHRONIZER_H_
diff --git a/ash/services/secure_channel/ble_synchronizer_base.cc b/ash/services/secure_channel/ble_synchronizer_base.cc
index 0f9c2020..305209f 100644
--- a/ash/services/secure_channel/ble_synchronizer_base.cc
+++ b/ash/services/secure_channel/ble_synchronizer_base.cc
@@ -6,9 +6,7 @@
 
 #include <memory>
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 BleSynchronizerBase::RegisterArgs::RegisterArgs(
     std::unique_ptr<device::BluetoothAdvertisement::Data> advertisement_data,
@@ -115,6 +113,4 @@
   ProcessQueue();
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_synchronizer_base.h b/ash/services/secure_channel/ble_synchronizer_base.h
index 1a9d483..4db4c37 100644
--- a/ash/services/secure_channel/ble_synchronizer_base.h
+++ b/ash/services/secure_channel/ble_synchronizer_base.h
@@ -12,9 +12,7 @@
 #include "device/bluetooth/bluetooth_advertisement.h"
 #include "device/bluetooth/bluetooth_discovery_session.h"
 
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 // Ensures that BLE advertisement registration/unregistration commands and
 // discovery start/stop are not sent too close to each other. Because Bluetooth
@@ -129,8 +127,11 @@
   std::deque<std::unique_ptr<Command>> command_queue_;
 };
 
-}  // namespace secure_channel
+}  // namespace ash::secure_channel
 
-}  // namespace chromeos
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace chromeos::secure_channel {
+using ::ash::secure_channel::BleSynchronizerBase;
+}
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_SYNCHRONIZER_BASE_H_
diff --git a/ash/services/secure_channel/ble_synchronizer_unittest.cc b/ash/services/secure_channel/ble_synchronizer_unittest.cc
index 20a89d2..d61de73 100644
--- a/ash/services/secure_channel/ble_synchronizer_unittest.cc
+++ b/ash/services/secure_channel/ble_synchronizer_unittest.cc
@@ -23,16 +23,14 @@
 #include "device/bluetooth/test/mock_bluetooth_advertisement.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using testing::_;
-using testing::Invoke;
-using testing::NiceMock;
-
-namespace chromeos {
-
-namespace secure_channel {
+namespace ash::secure_channel {
 
 namespace {
 
+using ::testing::_;
+using ::testing::Invoke;
+using ::testing::NiceMock;
+
 const char kId1[] = "id1";
 const char kId2[] = "id2";
 const char kId3[] = "id3";
@@ -623,6 +621,4 @@
   EXPECT_EQ(1, num_unregister_error_);
 }
 
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel
diff --git a/ash/services/secure_channel/ble_weave_client_connection.cc b/ash/services/secure_channel/ble_weave_client_connection.cc
index 685e458..3531a54 100644
--- a/ash/services/secure_channel/ble_weave_client_connection.cc
+++ b/ash/services/secure_channel/ble_weave_client_connection.cc
@@ -23,14 +23,13 @@
 #include "chromeos/components/multidevice/logging/logging.h"
 #include "device/bluetooth/bluetooth_gatt_connection.h"
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 namespace {
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace mojom = ::chromeos::secure_channel::mojom;
+
 typedef BluetoothLowEnergyWeavePacketReceiver::State ReceiverState;
 
 // The UUID of the TX characteristic used to transmit data to the server.
@@ -1060,8 +1059,4 @@
 
 BluetoothLowEnergyWeaveClientConnection::WriteRequest::~WriteRequest() {}
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
diff --git a/ash/services/secure_channel/ble_weave_client_connection.h b/ash/services/secure_channel/ble_weave_client_connection.h
index 71bf3cc..bd05d40 100644
--- a/ash/services/secure_channel/ble_weave_client_connection.h
+++ b/ash/services/secure_channel/ble_weave_client_connection.h
@@ -18,6 +18,8 @@
 #include "ash/services/secure_channel/file_transfer_update_callback.h"
 #include "ash/services/secure_channel/public/mojom/secure_channel_types.mojom.h"
 #include "ash/services/secure_channel/remote_attribute.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/wire_message.h"
 #include "base/callback.h"
 #include "base/containers/queue.h"
 #include "base/gtest_prod_util.h"
@@ -36,11 +38,7 @@
 class TaskRunner;
 }
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 // Creates GATT connection on top of the BLE connection and act as a Client.
 // uWeave communication follows the flow:
@@ -160,7 +158,7 @@
   void OnDidSendMessage(const WireMessage& message, bool success) override;
   void RegisterPayloadFileImpl(
       int64_t payload_id,
-      mojom::PayloadFilesPtr payload_files,
+      chromeos::secure_channel::mojom::PayloadFilesPtr payload_files,
       FileTransferUpdateCallback file_transfer_update_callback,
       base::OnceCallback<void(bool)> registration_result_callback) override;
 
@@ -452,10 +450,6 @@
       weak_ptr_factory_{this};
 };
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_WEAVE_CLIENT_CONNECTION_H_
diff --git a/ash/services/secure_channel/ble_weave_client_connection_unittest.cc b/ash/services/secure_channel/ble_weave_client_connection_unittest.cc
index 797318e..d0f0dcd 100644
--- a/ash/services/secure_channel/ble_weave_client_connection_unittest.cc
+++ b/ash/services/secure_channel/ble_weave_client_connection_unittest.cc
@@ -33,22 +33,16 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-using testing::_;
-using testing::AtLeast;
-using testing::DoAll;
-using testing::NiceMock;
-using testing::Return;
-using testing::SaveArg;
-using testing::StrictMock;
-
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 namespace {
 
+using ::testing::_;
+using ::testing::DoAll;
+using ::testing::NiceMock;
+using ::testing::Return;
+using ::testing::SaveArg;
+
 typedef BluetoothLowEnergyWeaveClientConnection::SubStatus SubStatus;
 typedef BluetoothLowEnergyWeavePacketReceiver::State ReceiverState;
 typedef BluetoothLowEnergyWeavePacketReceiver::ReceiverError ReceiverError;
@@ -1652,8 +1646,4 @@
   EXPECT_EQ(-30, GetRssi(connection.get()));
 }
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
diff --git a/ash/services/secure_channel/ble_weave_defines.h b/ash/services/secure_channel/ble_weave_defines.h
index e8550775..dbc9db5f 100644
--- a/ash/services/secure_channel/ble_weave_defines.h
+++ b/ash/services/secure_channel/ble_weave_defines.h
@@ -10,11 +10,7 @@
 
 #include <vector>
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 enum PacketType { DATA = 0x00, CONTROL = 0x01 };
 
@@ -52,10 +48,6 @@
 const uint8_t kByteSelectMaxPacketSize = 0;
 const uint8_t kEmptyUpperByte = 0;
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_WEAVE_DEFINES_H_
diff --git a/ash/services/secure_channel/ble_weave_packet_generator.cc b/ash/services/secure_channel/ble_weave_packet_generator.cc
index c545ceeb..a31755e75 100644
--- a/ash/services/secure_channel/ble_weave_packet_generator.cc
+++ b/ash/services/secure_channel/ble_weave_packet_generator.cc
@@ -17,11 +17,7 @@
 #include <netinet/in.h>
 #endif
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 BluetoothLowEnergyWeavePacketGenerator::BluetoothLowEnergyWeavePacketGenerator()
     : max_packet_size_(kDefaultMaxPacketSize), next_packet_counter_(0) {}
@@ -177,8 +173,4 @@
   packet->at(0) = packet->at(0) | (1 << 2);
 }
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
diff --git a/ash/services/secure_channel/ble_weave_packet_generator.h b/ash/services/secure_channel/ble_weave_packet_generator.h
index 52f0277..d183df6 100644
--- a/ash/services/secure_channel/ble_weave_packet_generator.h
+++ b/ash/services/secure_channel/ble_weave_packet_generator.h
@@ -15,11 +15,7 @@
 #include "ash/services/secure_channel/ble_weave_defines.h"
 #include "build/build_config.h"
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 // Generates the messages sent using the uWeave protocol.
 class BluetoothLowEnergyWeavePacketGenerator {
@@ -53,10 +49,6 @@
   uint8_t next_packet_counter_;
 };
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_WEAVE_PACKET_GENERATOR_H_
diff --git a/ash/services/secure_channel/ble_weave_packet_generator_unittest.cc b/ash/services/secure_channel/ble_weave_packet_generator_unittest.cc
index 6ef63ab7..97bc7bbf 100644
--- a/ash/services/secure_channel/ble_weave_packet_generator_unittest.cc
+++ b/ash/services/secure_channel/ble_weave_packet_generator_unittest.cc
@@ -11,11 +11,7 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 class SecureChannelBluetoothLowEnergyWeavePacketGeneratorTest
     : public testing::Test {
@@ -263,8 +259,4 @@
   }
 }
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
diff --git a/ash/services/secure_channel/ble_weave_packet_receiver.cc b/ash/services/secure_channel/ble_weave_packet_receiver.cc
index 69a2ee2..5796e289 100644
--- a/ash/services/secure_channel/ble_weave_packet_receiver.cc
+++ b/ash/services/secure_channel/ble_weave_packet_receiver.cc
@@ -16,11 +16,7 @@
 #include "base/notreached.h"
 #include "chromeos/components/multidevice/logging/logging.h"
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 namespace {
 
@@ -427,8 +423,4 @@
   return max_packet_size_;
 }
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
diff --git a/ash/services/secure_channel/ble_weave_packet_receiver.h b/ash/services/secure_channel/ble_weave_packet_receiver.h
index 14a08b3..5b72983 100644
--- a/ash/services/secure_channel/ble_weave_packet_receiver.h
+++ b/ash/services/secure_channel/ble_weave_packet_receiver.h
@@ -14,11 +14,7 @@
 #include "ash/services/secure_channel/ble_weave_defines.h"
 #include "build/build_config.h"
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 // Receive the messages sent with uWeave protocol.
 // Example Usage:
@@ -199,10 +195,6 @@
   ReceiverError receiver_error_;
 };
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_BLE_WEAVE_PACKET_RECEIVER_H_
diff --git a/ash/services/secure_channel/ble_weave_packet_receiver_unittest.cc b/ash/services/secure_channel/ble_weave_packet_receiver_unittest.cc
index f478bce..c8ce4f1 100644
--- a/ash/services/secure_channel/ble_weave_packet_receiver_unittest.cc
+++ b/ash/services/secure_channel/ble_weave_packet_receiver_unittest.cc
@@ -11,11 +11,7 @@
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-namespace chromeos {
-
-namespace secure_channel {
-
-namespace weave {
+namespace ash::secure_channel::weave {
 
 namespace {
 
@@ -38,6 +34,7 @@
 // ---- 0001 : command = 1 (response)
 // 1000 0001 = 0x81
 const uint8_t kControlResponseHeader = 0x81;
+
 }  // namespace
 
 class SecureChannelBluetoothLowEnergyWeavePacketReceiverTest
@@ -1027,8 +1024,4 @@
             receiver->GetReceiverError());
 }
 
-}  // namespace weave
-
-}  // namespace secure_channel
-
-}  // namespace chromeos
+}  // namespace ash::secure_channel::weave
diff --git a/ash/services/secure_channel/connect_to_device_operation.h b/ash/services/secure_channel/connect_to_device_operation.h
index 461b71c..850a400 100644
--- a/ash/services/secure_channel/connect_to_device_operation.h
+++ b/ash/services/secure_channel/connect_to_device_operation.h
@@ -115,4 +115,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectToDeviceOperation;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECT_TO_DEVICE_OPERATION_H_
diff --git a/ash/services/secure_channel/connect_to_device_operation_base.h b/ash/services/secure_channel/connect_to_device_operation_base.h
index 70b5368e..93c4ea1 100644
--- a/ash/services/secure_channel/connect_to_device_operation_base.h
+++ b/ash/services/secure_channel/connect_to_device_operation_base.h
@@ -118,4 +118,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectToDeviceOperationBase;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECT_TO_DEVICE_OPERATION_BASE_H_
diff --git a/ash/services/secure_channel/connection.h b/ash/services/secure_channel/connection.h
index 42a8f74..89a456a 100644
--- a/ash/services/secure_channel/connection.h
+++ b/ash/services/secure_channel/connection.h
@@ -154,4 +154,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::Connection;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_H_
diff --git a/ash/services/secure_channel/connection_attempt.h b/ash/services/secure_channel/connection_attempt.h
index 5b4d550..0534fac 100644
--- a/ash/services/secure_channel/connection_attempt.h
+++ b/ash/services/secure_channel/connection_attempt.h
@@ -141,4 +141,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectionAttempt;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_ATTEMPT_H_
diff --git a/ash/services/secure_channel/connection_attempt_base.h b/ash/services/secure_channel/connection_attempt_base.h
index fe4356f..aae6164 100644
--- a/ash/services/secure_channel/connection_attempt_base.h
+++ b/ash/services/secure_channel/connection_attempt_base.h
@@ -181,4 +181,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectionAttemptBase;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_ATTEMPT_BASE_H_
diff --git a/ash/services/secure_channel/connection_attempt_delegate.h b/ash/services/secure_channel/connection_attempt_delegate.h
index c15c947e..ff651537 100644
--- a/ash/services/secure_channel/connection_attempt_delegate.h
+++ b/ash/services/secure_channel/connection_attempt_delegate.h
@@ -47,4 +47,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectionAttemptDelegate;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_ATTEMPT_DELEGATE_H_
diff --git a/ash/services/secure_channel/connection_attempt_details.h b/ash/services/secure_channel/connection_attempt_details.h
index 98b4539..b246f97 100644
--- a/ash/services/secure_channel/connection_attempt_details.h
+++ b/ash/services/secure_channel/connection_attempt_details.h
@@ -69,4 +69,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectionAttemptDetails;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_ATTEMPT_DETAILS_H_
diff --git a/ash/services/secure_channel/connection_metrics_logger.h b/ash/services/secure_channel/connection_metrics_logger.h
index 42c5583..c9bdf06 100644
--- a/ash/services/secure_channel/connection_metrics_logger.h
+++ b/ash/services/secure_channel/connection_metrics_logger.h
@@ -41,4 +41,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::LogLatencyMetric;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_METRICS_LOGGER_H_
diff --git a/ash/services/secure_channel/connection_observer.h b/ash/services/secure_channel/connection_observer.h
index fca06a5..086fd52 100644
--- a/ash/services/secure_channel/connection_observer.h
+++ b/ash/services/secure_channel/connection_observer.h
@@ -40,4 +40,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectionObserver;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_OBSERVER_H_
diff --git a/ash/services/secure_channel/connection_role.h b/ash/services/secure_channel/connection_role.h
index 1efc414..a44f756 100644
--- a/ash/services/secure_channel/connection_role.h
+++ b/ash/services/secure_channel/connection_role.h
@@ -27,4 +27,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::ConnectionRole;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_CONNECTION_ROLE_H_
diff --git a/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.cc b/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.cc
index 75c9610e..fefdcda 100644
--- a/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.cc
+++ b/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.cc
@@ -7,7 +7,7 @@
 #include <memory>
 
 #include "ash/services/secure_channel/ble_constants.h"
-#include "ash/services/secure_channel/ble_synchronizer.h"
+#include "ash/services/secure_channel/ble_synchronizer_base.h"
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/weak_ptr.h"
diff --git a/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.h b/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.h
index 112bde0..e9c35d5 100644
--- a/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.h
+++ b/ash/services/secure_channel/error_tolerant_ble_advertisement_impl.h
@@ -8,6 +8,8 @@
 #include <memory>
 #include <string>
 
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_synchronizer_base.h"
 #include "ash/services/secure_channel/device_id_pair.h"
 #include "ash/services/secure_channel/error_tolerant_ble_advertisement.h"
 #include "ash/services/secure_channel/foreground_eid_generator.h"
@@ -18,8 +20,6 @@
 
 namespace secure_channel {
 
-class BleSynchronizerBase;
-
 // Concrete ErrorTolerantBleAdvertisement implementation.
 class ErrorTolerantBleAdvertisementImpl
     : public ErrorTolerantBleAdvertisement,
diff --git a/ash/services/secure_channel/fake_background_eid_generator.h b/ash/services/secure_channel/fake_background_eid_generator.h
index 55ce15b..dfb145e 100644
--- a/ash/services/secure_channel/fake_background_eid_generator.h
+++ b/ash/services/secure_channel/fake_background_eid_generator.h
@@ -59,4 +59,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::FakeBackgroundEidGenerator;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_FAKE_BACKGROUND_EID_GENERATOR_H_
diff --git a/ash/services/secure_channel/fake_ble_advertiser.h b/ash/services/secure_channel/fake_ble_advertiser.h
index 471ba61..477ad95 100644
--- a/ash/services/secure_channel/fake_ble_advertiser.h
+++ b/ash/services/secure_channel/fake_ble_advertiser.h
@@ -109,7 +109,8 @@
 
 // TODO(https://crbug.com/1164001): remove after the migration is finished.
 namespace ash::secure_channel {
+using ::chromeos::secure_channel::FakeBleAdvertiser;
 using ::chromeos::secure_channel::FakeBleAdvertiserDelegate;
-}
+}  // namespace ash::secure_channel
 
 #endif  // ASH_SERVICES_SECURE_CHANNEL_FAKE_BLE_ADVERTISER_H_
diff --git a/ash/services/secure_channel/fake_ble_connection_manager.h b/ash/services/secure_channel/fake_ble_connection_manager.h
index 334c456..846e0e7 100644
--- a/ash/services/secure_channel/fake_ble_connection_manager.h
+++ b/ash/services/secure_channel/fake_ble_connection_manager.h
@@ -57,4 +57,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::FakeBleConnectionManager;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_FAKE_BLE_CONNECTION_MANAGER_H_
diff --git a/ash/services/secure_channel/fake_ble_scanner.h b/ash/services/secure_channel/fake_ble_scanner.h
index 7a99ab7b..93d146f 100644
--- a/ash/services/secure_channel/fake_ble_scanner.h
+++ b/ash/services/secure_channel/fake_ble_scanner.h
@@ -82,4 +82,10 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::FakeBleScanner;
+using ::chromeos::secure_channel::FakeBleScannerObserver;
+}  // namespace ash::secure_channel
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_FAKE_BLE_SCANNER_H_
diff --git a/ash/services/secure_channel/fake_secure_channel_disconnector.h b/ash/services/secure_channel/fake_secure_channel_disconnector.h
index bc4399e..15584c9 100644
--- a/ash/services/secure_channel/fake_secure_channel_disconnector.h
+++ b/ash/services/secure_channel/fake_secure_channel_disconnector.h
@@ -44,4 +44,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::FakeSecureChannelDisconnector;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_FAKE_SECURE_CHANNEL_DISCONNECTOR_H_
diff --git a/ash/services/secure_channel/fake_wire_message.h b/ash/services/secure_channel/fake_wire_message.h
index 7bc40e7..d50d381 100644
--- a/ash/services/secure_channel/fake_wire_message.h
+++ b/ash/services/secure_channel/fake_wire_message.h
@@ -29,4 +29,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::FakeWireMessage;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_FAKE_WIRE_MESSAGE_H_
diff --git a/ash/services/secure_channel/pending_connection_manager_impl.h b/ash/services/secure_channel/pending_connection_manager_impl.h
index e185c59..caf7f4c 100644
--- a/ash/services/secure_channel/pending_connection_manager_impl.h
+++ b/ash/services/secure_channel/pending_connection_manager_impl.h
@@ -8,6 +8,8 @@
 #include <memory>
 #include <vector>
 
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_connection_manager.h"
 #include "ash/services/secure_channel/ble_initiator_failure_type.h"
 #include "ash/services/secure_channel/ble_listener_failure_type.h"
 #include "ash/services/secure_channel/client_connection_parameters.h"
@@ -27,7 +29,6 @@
 
 namespace secure_channel {
 
-class BleConnectionManager;
 class NearbyConnectionManager;
 
 // Concrete PendingConnectionManager implementation. This class creates one
diff --git a/ash/services/secure_channel/presence_monitor_delegate.h b/ash/services/secure_channel/presence_monitor_delegate.h
index b198836c..fcc85ab 100644
--- a/ash/services/secure_channel/presence_monitor_delegate.h
+++ b/ash/services/secure_channel/presence_monitor_delegate.h
@@ -6,6 +6,8 @@
 #define ASH_SERVICES_SECURE_CHANNEL_PRESENCE_MONITOR_DELEGATE_H_
 
 #include "ash/services/secure_channel/ble_scanner.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_synchronizer_base.h"
 #include "ash/services/secure_channel/public/cpp/shared/presence_monitor.h"
 
 namespace device {
@@ -22,7 +24,6 @@
 
 namespace secure_channel {
 
-class BleSynchronizerBase;
 class BluetoothHelper;
 
 // Monitors device proximity while a secure channel is active.
diff --git a/ash/services/secure_channel/remote_attribute.h b/ash/services/secure_channel/remote_attribute.h
index 738346d..18e33819 100644
--- a/ash/services/secure_channel/remote_attribute.h
+++ b/ash/services/secure_channel/remote_attribute.h
@@ -23,4 +23,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::RemoteAttribute;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_REMOTE_ATTRIBUTE_H_
diff --git a/ash/services/secure_channel/secure_channel_disconnector.h b/ash/services/secure_channel/secure_channel_disconnector.h
index 584da5c2..2447f46 100644
--- a/ash/services/secure_channel/secure_channel_disconnector.h
+++ b/ash/services/secure_channel/secure_channel_disconnector.h
@@ -37,4 +37,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::SecureChannelDisconnector;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_SECURE_CHANNEL_DISCONNECTOR_H_
diff --git a/ash/services/secure_channel/secure_channel_impl.h b/ash/services/secure_channel/secure_channel_impl.h
index 3b829ffe..bc5ec3aa 100644
--- a/ash/services/secure_channel/secure_channel_impl.h
+++ b/ash/services/secure_channel/secure_channel_impl.h
@@ -11,6 +11,12 @@
 #include <vector>
 
 #include "ash/services/secure_channel/active_connection_manager.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_connection_manager.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_scanner.h"
+// TODO(https://crbug.com/1164001): move to forward declaration.
+#include "ash/services/secure_channel/ble_synchronizer_base.h"
 #include "ash/services/secure_channel/connection_attempt_details.h"
 #include "ash/services/secure_channel/pending_connection_manager.h"
 #include "ash/services/secure_channel/public/cpp/shared/connection_priority.h"
@@ -27,10 +33,7 @@
 
 namespace secure_channel {
 
-class BleConnectionManager;
-class BleScanner;
 class BluetoothHelper;
-class BleSynchronizerBase;
 class NearbyConnectionManager;
 class SecureChannelDisconnector;
 class TimerFactory;
diff --git a/ash/services/secure_channel/wire_message.h b/ash/services/secure_channel/wire_message.h
index d5281e0..2478e7c6 100644
--- a/ash/services/secure_channel/wire_message.h
+++ b/ash/services/secure_channel/wire_message.h
@@ -98,4 +98,9 @@
 
 }  // namespace chromeos
 
+// TODO(https://crbug.com/1164001): remove after the migration is finished.
+namespace ash::secure_channel {
+using ::chromeos::secure_channel::WireMessage;
+}
+
 #endif  // ASH_SERVICES_SECURE_CHANNEL_WIRE_MESSAGE_H_
diff --git a/chromeos/components/multidevice/logging/logging.h b/chromeos/components/multidevice/logging/logging.h
index 6cd7a46..9b504b593 100644
--- a/chromeos/components/multidevice/logging/logging.h
+++ b/chromeos/components/multidevice/logging/logging.h
@@ -65,8 +65,9 @@
 // TODO(https://crbug.com/1164001): remove after the migration is finished.
 namespace ash {
 namespace multidevice {
+using ::chromeos::multidevice::ScopedDisableLoggingForTesting;
 using ::chromeos::multidevice::ScopedLogMessage;
-}
+}  // namespace multidevice
 }  // namespace ash
 
 #endif  // CHROMEOS_COMPONENTS_MULTIDEVICE_LOGGING_LOGGING_H_
diff --git a/chromeos/components/multidevice/remote_device_test_util.h b/chromeos/components/multidevice/remote_device_test_util.h
index c5e3108..fde71b3 100644
--- a/chromeos/components/multidevice/remote_device_test_util.h
+++ b/chromeos/components/multidevice/remote_device_test_util.h
@@ -71,6 +71,7 @@
 using ::chromeos::multidevice::CreateRemoteDeviceRefForTest;
 using ::chromeos::multidevice::CreateRemoteDeviceRefListForTest;
 using ::chromeos::multidevice::RemoteDeviceRefBuilder;
+using ::chromeos::multidevice::kTestRemoteDeviceName;
 }  // namespace multidevice
 }  // namespace ash