Fix include guards in //device/usb

device/usb/usb_service_impl.h

Index: device/usb/usb_service_impl.h
diff --git a/device/usb/usb_service_impl.h b/device/usb/usb_service_impl.h
index 0014dd31ff0b2fdf5b1a4db30a00b05dfb2261f9..ec441bf529d262a4bb6dc48b57919fd465f1f20b 100644
--- a/device/usb/usb_service_impl.h
+++ b/device/usb/usb_service_impl.h
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifndef DEVICE_USB_USB_SERVICE_IMPL_H_
+#define DEVICE_USB_USB_SERVICE_IMPL_H_
+
 #include "device/usb/usb_service.h"
 
 #include <stddef.h>
@@ -120,3 +123,5 @@ class UsbServiceImpl :
 };
 
 }  // namespace device
+
+#endif  // DEVICE_USB_USB_SERVICE_IMPL_H_