Use xvfb with Ozone CrOS.

testing/buildbot/gn_isolate_map.pyl

Index: testing/buildbot/gn_isolate_map.pyl
diff --git a/testing/buildbot/gn_isolate_map.pyl b/testing/buildbot/gn_isolate_map.pyl
index 1904a63db1c5f6197b0e5a62ad99fdb2cf5f947e..fd18d230858bae01c4d6ce51497447a0c666d745 100644
--- a/testing/buildbot/gn_isolate_map.pyl
+++ b/testing/buildbot/gn_isolate_map.pyl
@@ -20,8 +20,7 @@
 #  "windowed_test_launcher"
 #  : the test is a gtest-based test that uses the "brave-new-test-launcher"
 #    from //base/test:test_support and needs to run under Xvfb if run on
-#    an X11-based platform (use_x11=true or use_ozone=true &&
-#    --ozone_platform=x11).
+#    some platforms (eg. Linux Desktop, X11 CrOS and Ozone CrOS).
 #  "console_test_launcher"
 #  : the test is a gtest-based test that uses the "brave-new-test-launcher"
 #    from //base/test:test_support but does not need Xvfb.
@@ -450,15 +449,8 @@
   },
   "gl_unittests": {
     "label": "//ui/gl:gl_unittests",
-    "type": "raw",
-    "args": [],
-  },
-  "gl_unittests_ozonex": {
-    "label": "//ui/gl:gl_unittests_ozonex",
-    "label_type": "group",
     "type": "windowed_test_launcher",
-    "executable": "gl_unittests",
-    "args": ["--ozone-platform=x11"],
+    "args": [],
   },
   "gn_all": {
     "label": "//:gn_all",