Tether: Break helper TimerFactory out of BleConnectionManager and HostScanCache.

chromeos/components/tether/ble_connection_manager.h

Index: chromeos/components/tether/ble_connection_manager.h
diff --git a/chromeos/components/tether/ble_connection_manager.h b/chromeos/components/tether/ble_connection_manager.h
index c6d73c4d5f5558ab8a1ea5186e37da5e02d68c6c..e69cdcef74f0bab9fba1e24b00624f2027562188 100644
--- a/chromeos/components/tether/ble_connection_manager.h
+++ b/chromeos/components/tether/ble_connection_manager.h
@@ -29,6 +29,8 @@ namespace chromeos {
 
 namespace tether {
 
+class TimerFactory;
+
 // Manages connections to remote devices. When a device is registered,
 // BleConnectionManager intiates a connection to that device. If the connection
 // succeeds and authenticates successfully, messages can be sent/received
@@ -109,11 +111,6 @@ class BleConnectionManager : public BleScanner::Observer {
       cryptauth::RemoteDevice remote_device) override;
 
  protected:
-  class TimerFactory {
-   public:
-    virtual std::unique_ptr<base::Timer> CreateTimer();
-  };
-
   BleConnectionManager(
       cryptauth::CryptAuthService* cryptauth_service,
       scoped_refptr<device::BluetoothAdapter> adapter,