Move display_service_unittests to services_unittests.

services/ui/display/BUILD.gn

 # Copyright 2016 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/ui.gni")
 import("//testing/test.gni")
 
 source_set("display") {
   sources = [
     "screen_manager.cc",
@@ skipping 37 matching lines @@
     }
   } else {
     sources += [
       "screen_manager_stub_internal.cc",
       "screen_manager_stub_internal.h",
     ]
   }
 }
 
 if (use_ozone && is_chromeos) {
-  test("display_service_unittests") {
+  source_set("tests") {
+    testonly = true
+
     sources = [
-      "run_all_unittests.cc",
       "screen_manager_ozone_internal_unittests.cc",
     ]
 
     deps = [
       ":display",
       "//base",
       "//base/test:test_support",
       "//services/ui/common:task_runner_test_base",
       "//testing/gmock",
       "//testing/gtest",
       "//ui/base",
       "//ui/display",
       "//ui/events/devices",
       "//ui/gfx",
       "//ui/gfx:test_support",
       "//ui/ozone",
     ]
 
     data_deps = [
       "//ui/resources:ui_test_pak_data",
     ]
   }
 }