ozone gbm: whitelist 3 DRM ioctl code for native GpuMemoryBuffer.

ui/ozone/ozone.gni

 # 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.
 
 import("//build/config/chromecast_build.gni")
 
 declare_args() {
   # Select platforms automatically. Turn this off for manual control.
   ozone_auto_platforms = true
+
+  # This enables memory-mapped access to accelerated graphics buffers via the
+  # VGEM ("virtual GEM") driver. This is currently only available on Chrome OS
+  # kernels and affects code in the GBM ozone platform.
+  # TODO(dshwang): remove this flag when all gbm hardware supports vgem map.
+  # crbug.com/519587
+  use_vgem_map = false
 }
 
 declare_args() {
   # The platform that will be active by default.
   ozone_platform = ""
 
   # Enable individual platforms.
   ozone_platform_caca = false
   ozone_platform_cast = false
   ozone_platform_egltest = false
@@ skipping 19 matching lines @@
       ozone_platform = "test"
 
       # Build all platforms whose deps are in install-build-deps.sh.
       # Only these platforms will be compile tested by buildbots.
       ozone_platform_gbm = true
       ozone_platform_test = true
       ozone_platform_egltest = true
     }
   }
 }