Make udev target disappear on linux when use_udev==0

components/usb_service.gypi

 # 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.
 
 {
   'targets': [{
     # GN version: //components/usb_service
     'target_name': 'usb_service',
     'type': '<(component)',
     'dependencies': [
@@ skipping 21 matching lines @@
       'usb_service/usb_device_handle.h',
       'usb_service/usb_error.cc',
       'usb_service/usb_error.h',
       'usb_service/usb_interface.h',
       'usb_service/usb_interface_impl.cc',
       'usb_service/usb_interface_impl.h',
       'usb_service/usb_service.h',
       'usb_service/usb_service_impl.cc',
     ],
     'conditions': [
-      ['OS == "linux"', {
+      ['use_udev == 1', {
         'dependencies': [
           '../build/linux/system.gyp:udev',
         ],
       }],
       ['chromeos==1', {
         'dependencies': [
           '../chromeos/chromeos.gyp:chromeos',
         ],
       }],
     ]
   }],
 }