Revert of ozone: Remove the "drm" software composited platform

ui/ozone/ozone.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,
     # Normally, the external_ozone_platform* variables below can be
     # overridden by supplement.gypi which must exist exactly one level
     # below the top-level src directory. They can now also be set in
@@ skipping 192 matching lines @@
     ['<(ozone_platform_caca) == 1', {
       'includes': [
         'platform/caca/caca.gypi',
       ],
     }],
     ['<(ozone_platform_cast) == 1', {
       'includes': [
         'platform/cast/cast.gypi',
       ],
     }],
+    ['<(ozone_platform_drm) == 1 or <(ozone_platform_gbm) == 1', {
+      'includes': [
+        'platform/drm/drm.gypi',
+      ],
+    }],
     ['<(ozone_platform_egltest) == 1', {
       'includes': [
         'platform/egltest/egltest.gypi',
       ],
     }],
     ['<(ozone_platform_gbm) == 1', {
       'includes': [
         'platform/drm/gbm.gypi',
       ],
     }],
     ['<(ozone_platform_test) == 1', {
       'includes': [
         'platform/test/test.gypi',
       ],
     }],
   ],
 }