Revert of Move gn _run target generation into test().

ui/display/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/config/ui.gni")
 import("//testing/test.gni")
 
 if (is_chromeos) {
   component("display") {
     sources = [
@@ skipping 112 matching lines @@
     deps = [
       "//base",
       "//ui/display/types",
       "//ui/gfx",
       "//ui/gfx:test_support",
       "//ui/gfx/geometry",
     ]
   }
 }
 
+# TODO(GYP): Delete this after we've converted everything to GN.
+# The _run targets exist only for compatibility w/ GYP.
+group("display_unittests_run") {
+  testonly = true
+  deps = [
+    ":display_unittests",
+  ]
+}
+
 # This test covers the ChromeOS "display" target as well as the cross-platform
 # //display/util target.
 test("display_unittests") {
   sources = [
     "chromeos/apply_content_protection_task_unittest.cc",
     "chromeos/configure_displays_task_unittest.cc",
     "chromeos/display_configurator_unittest.cc",
     "chromeos/query_content_protection_task_unittest.cc",
     "chromeos/update_display_configuration_task_unittest.cc",
     "chromeos/x11/display_util_x11_unittest.cc",
@@ skipping 20 matching lines @@
     ]
   }
 
   if (use_ozone && is_chromeos) {
     sources -= [
       "chromeos/x11/display_util_x11_unittest.cc",
       "chromeos/x11/native_display_event_dispatcher_x11_unittest.cc",
     ]
   }
 }