Tether: Break helper TimerFactory out of BleConnectionManager and HostScanCache.

chromeos/components/tether/ble_connection_manager.cc

Index: chromeos/components/tether/ble_connection_manager.cc
diff --git a/chromeos/components/tether/ble_connection_manager.cc b/chromeos/components/tether/ble_connection_manager.cc
index 78401ed06deddd724787b7c9cbab5f7576256b08..18cb02a2109b1abbe868a7f2959ffe221a69dd96 100644
--- a/chromeos/components/tether/ble_connection_manager.cc
+++ b/chromeos/components/tether/ble_connection_manager.cc
@@ -5,6 +5,7 @@
 #include "chromeos/components/tether/ble_connection_manager.h"
 
 #include "chromeos/components/tether/ble_constants.h"
+#include "chromeos/components/tether/timer_factory.h"
 #include "components/cryptauth/ble/bluetooth_low_energy_weave_client_connection.h"
 #include "components/cryptauth/cryptauth_service.h"
 #include "components/proximity_auth/logging/logging.h"
@@ -165,10 +166,6 @@ void BleConnectionManager::ConnectionMetadata::OnMessageReceived(
   manager_->SendMessageReceivedEvent(remote_device_, payload);
 }
 
-std::unique_ptr<base::Timer> BleConnectionManager::TimerFactory::CreateTimer() {
-  return base::MakeUnique<base::OneShotTimer>();
-}
-
 BleConnectionManager::BleConnectionManager(
     cryptauth::CryptAuthService* cryptauth_service,
     scoped_refptr<device::BluetoothAdapter> adapter,
@@ -183,7 +180,7 @@ BleConnectionManager::BleConnectionManager(
                                           local_device_data_provider,
                                           remote_beacon_seed_fetcher),
           base::MakeUnique<BleAdvertisementDeviceQueue>(),
-          base::WrapUnique<TimerFactory>(new TimerFactory()),
+          base::MakeUnique<TimerFactory>(),
           bluetooth_throttler) {}
 
 BleConnectionManager::BleConnectionManager(
@@ -372,7 +369,7 @@ BleConnectionManager::AddMetadataForDevice(
     return existing_data;
   }
 
-  std::unique_ptr<base::Timer> timer = timer_factory_->CreateTimer();
+  std::unique_ptr<base::Timer> timer = timer_factory_->CreateOneShotTimer();
   device_to_metadata_map_.insert(
       std::pair<cryptauth::RemoteDevice, std::shared_ptr<ConnectionMetadata>>(
           remote_device,