Linux: Unify udev scopers.

device/hid/hid.gyp

 # Copyright 2013 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': [
     {
       'target_name': 'device_hid',
       'type': 'static_library',
       'include_dirs': [
         '../..',
       ],
       'conditions': [
-        ['OS=="linux"', {
+        ['use_udev==1', {
           'dependencies': [
-            '../../build/linux/system.gyp:udev',
+            '../udev_linux/udev.gyp:udev_linux',
           ],
         }],
       ],
       'sources': [
         'device_monitor_linux.cc',
         'device_monitor_linux.h',
         'hid_connection.cc',
         'hid_connection.h',
         'hid_connection_linux.cc',
         'hid_connection_linux.h',
@@ skipping 14 matching lines @@
         'hid_service_mac.cc',
         'hid_service_mac.h',
         'hid_service_win.cc',
         'hid_service_win.h',
         'hid_usage_and_page.cc',
         'hid_usage_and_page.h',
         'hid_utils_mac.cc',
         'hid_utils_mac.h',
         'input_service_linux.cc',
         'input_service_linux.h',
-        'udev_common.h'
       ],
     },
   ],
 }