Add plane manager to the atomic swap path.

ui/ozone/platform/dri/dri.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_dri',
     ],
     'internal_ozone_platform_unittest_deps': [
@@ skipping 58 matching lines @@
         'screen_manager.h',
         'scanout_buffer.h',
         'virtual_terminal_manager.cc',
         'virtual_terminal_manager.h',
       ],
       'conditions': [
         ['use_drm_atomic_flip==1', {
           'sources': [
             'hardware_display_plane.cc',
             'hardware_display_plane.h',
+            'hardware_display_plane_manager.cc',
+            'hardware_display_plane_manager.h',
           ],
         }],
       ],      
     },
     {
       'target_name': 'ozone_platform_dri_unittests',
       'type': 'none',
       'dependencies': [
         '../../build/linux/system.gyp:dridrm',
         '../../skia/skia.gyp:skia',
@@ skipping 11 matching lines @@
           'dri_surface_unittest.cc',
           'hardware_display_controller_unittest.cc',
           'screen_manager_unittest.cc',
           'test/mock_dri_wrapper.cc',
           'test/mock_dri_wrapper.h',
         ],
       },
     },
   ],
 }