Reland: Run gl_unittests with Ozone X11.

ui/gl/BUILD.gn

Index: ui/gl/BUILD.gn
diff --git a/ui/gl/BUILD.gn b/ui/gl/BUILD.gn
index 69262b487beae6ba61cf145e783b4455e2846df5..5050c8915560eea009e18c328392f4dac7dc0be8 100644
--- a/ui/gl/BUILD.gn
+++ b/ui/gl/BUILD.gn
@@ -404,6 +404,27 @@ test("gl_unittests") {
   ]
 }
 
+# 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",
+      "//tools/xdisplaycheck",
+    ]
+  }
+
+  # 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"