Make chrome/common compile in GN

device/serial/serial.gyp

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
+      # GN version: //device/serial
       'target_name': 'device_serial',
       'type': 'static_library',
       'include_dirs': [
         '../..',
       ],
       'conditions': [
         ['OS=="linux"', {
           'dependencies': [
             '../../build/linux/system.gyp:udev',
           ],
@@ skipping 12 matching lines @@
         'serial_device_enumerator_linux.cc',
         'serial_device_enumerator_linux.h',
         'serial_device_enumerator_mac.cc',
         'serial_device_enumerator_mac.h',
         'serial_device_enumerator_win.cc',
         'serial_device_enumerator_win.h',
       ],
     },
   ],
 }