events: Create a separate platforms target.

ui/events/ozone/events_ozone.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': [{
     'target_name': 'events_ozone',
@@ skipping 30 matching lines @@
           '<(DEPTH)/build/linux/system.gyp:udev',
         ],
       }],
     ],
   }, {
     'target_name': 'events_ozone_evdev',
     'type': '<(component)',
     'dependencies': [
       '../../../base/base.gyp:base',
       '../../gfx/gfx.gyp:gfx',
+      '../platform/events_platform.gyp:events_platform',
       'events_ozone',
     ],
     'defines': [
       'EVENTS_OZONE_EVDEV_IMPLEMENTATION',
     ],
     'sources': [
       'evdev/libgestures_glue/event_reader_libevdev_cros.cc',
       'evdev/libgestures_glue/event_reader_libevdev_cros.h',
       'evdev/libgestures_glue/gesture_interpreter_libevdev_cros.cc',
       'evdev/libgestures_glue/gesture_interpreter_libevdev_cros.h',
@@ skipping 22 matching lines @@
           '<(DEPTH)/build/linux/system.gyp:libevdev-cros',
         ],
         'defines': [
           'USE_EVDEV_GESTURES',
         ],
       }, {
         'sources/': [
           ['exclude', '^evdev/libgestures_glue/'],
         ],
       }],
+      ['use_ozone_evdev==1', {
+        'defines': ['USE_OZONE_EVDEV=1'],
+      }],
     ],
   }]
 }