Move all event related devices from ui/events/ to ui/events/devices/

ui/events/platform/x11/x11_events_platform.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: //ui/events/platform/x11
     'target_name': 'x11_events_platform',
     'type': '<(component)',
     'defines': [
       'EVENTS_IMPLEMENTATION',
     ],
     'dependencies': [
       '../../../../build/linux/system.gyp:x11',
       '../../../gfx/x/gfx_x11.gyp:gfx_x11',
+      '../../devices/events_devices.gyp:events_devices',
       '../../events.gyp:events',
       '../../events.gyp:events_base',
       '../events_platform.gyp:events_platform',
     ],
     'sources': [
       'x11_event_source.cc',
       'x11_event_source.h',
       'x11_event_source_glib.cc',
       'x11_event_source_libevent.cc',
+      'x11_hotplug_event_handler.cc',
+      'x11_hotplug_event_handler.h',
     ],
     'conditions': [
       ['use_glib==1', {
         'dependencies': [
           '../../../../build/linux/system.gyp:glib',
         ],
         'sources!': [
           'x11_event_source_libevent.cc',
         ],
       }, {
         # use_glib == 0
         'sources!': [
           'x11_event_source_glib.cc',
         ],
       }],
     ],
   }],
 }