[Ozone-Drm] Remove GPU lock

ui/ozone/platform/drm/drm.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.
 
 {
   'variables': {
     'internal_ozone_platform_deps': [
       'ozone_platform_drm',
     ],
     'internal_ozone_platform_unittest_deps': [
@@ skipping 51 matching lines @@
         'gpu/drm_gpu_display_manager.cc',
         'gpu/drm_gpu_display_manager.h',
         'gpu/drm_gpu_platform_support.cc',
         'gpu/drm_gpu_platform_support.h',
         'gpu/drm_surface.cc',
         'gpu/drm_surface.h',
         'gpu/drm_vsync_provider.cc',
         'gpu/drm_vsync_provider.h',
         'gpu/drm_window.cc',
         'gpu/drm_window.h',
-        'gpu/gpu_lock.cc',
-        'gpu/gpu_lock.h',
         'gpu/hardware_display_controller.cc',
         'gpu/hardware_display_controller.h',
         'gpu/hardware_display_plane.cc',
         'gpu/hardware_display_plane.h',
         'gpu/hardware_display_plane_manager.cc',
         'gpu/hardware_display_plane_manager.h',
         'gpu/hardware_display_plane_manager_legacy.cc',
         'gpu/hardware_display_plane_manager_legacy.h',
         'gpu/overlay_plane.cc',
         'gpu/overlay_plane.h',
@@ skipping 42 matching lines @@
           'gpu/hardware_display_controller_unittest.cc',
           'gpu/hardware_display_plane_manager_unittest.cc',
           'gpu/screen_manager_unittest.cc',
           'test/mock_drm_device.cc',
           'test/mock_drm_device.h',
         ],
       },
     },
   ],
 }