Use xvfb with Ozone CrOS.

ui/gl/BUILD.gn

 # 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/buildflag_header.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/linux/pkg_config.gni")
 import("//build/config/ui.gni")
 import("//ui/ozone/ozone.gni")
 import("//testing/test.gni")
@@ skipping 390 matching lines @@
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl/init",
   ]
 
   data_deps = [
     "//third_party/mesa:osmesa",
   ]
 }
 
-# Non-Ozone trybots end up trying to build this when building "all" and failing
-# when X11 isn't there.
-if (ozone_platform_x11) {
-  group("gl_unittests_ozonex") {
-    testonly = true
-    data_deps = [
-      ":gl_unittests",
-    ]
-  }
-
-  # TODO(GYP_GONE): Delete this after we've converted everything to GN.
-  # The _run targets exist only for compatibility w/ GYP.
-  group("gl_unittests_ozonex_run") {
-    testonly = true
-    deps = [
-      ":gl_unittests_ozonex",
-    ]
-  }
-}
-
 if (is_android) {
   generate_jar_jni("surface_jni_headers") {
     jni_package = "ui/gl"
     classes = [ "android/view/Surface.class" ]
   }
 
   generate_jni("gl_jni_headers") {
     sources = [
       "../android/java/src/org/chromium/ui/gl/SurfaceTextureListener.java",
       "../android/java/src/org/chromium/ui/gl/SurfaceTexturePlatformWrapper.java",
     ]
     public_deps = [
       ":surface_jni_headers",
     ]
     jni_package = "ui/gl"
   }
 }