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

ui/ozone/platform/drm/gbm.gypi

Index: ui/ozone/platform/drm/gbm.gypi
diff --git a/ui/ozone/platform/drm/gbm.gypi b/ui/ozone/platform/drm/gbm.gypi
index 379e1091060fc551cb4df0846a19fe93d846cfe9..f0922c861d0c5c1c8ac705d3539055407da28fc1 100644
--- a/ui/ozone/platform/drm/gbm.gypi
+++ b/ui/ozone/platform/drm/gbm.gypi
@@ -11,10 +11,6 @@
       'gbm',
     ],
     'use_mesa_platform_null%': 0,
-
-    # TODO(dshwang): remove this flag when all gbm hardware supports vgem map.
-    # crbug.com/519587
-    'use_vgem_map%': 0,
   },
   'targets': [
     {
@@ -59,7 +55,9 @@
           'defines': ['USE_MESA_PLATFORM_NULL'],
         }],
         ['use_vgem_map==1', {
-          'defines': ['USE_VGEM_MAP'],
+          'dependencies': [
+            '../../build/linux/system.gyp:vgem_map',
+          ],
           'sources': [
             'gpu/client_native_pixmap_vgem.cc',
             'gpu/client_native_pixmap_vgem.h',