Add a mojom/StructTrait for display::Display.

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")
 
 component("display") {
   sources = [
     "android/screen_android.cc",
@@ skipping 177 matching lines @@
     "util/display_util_unittest.cc",
     "util/edid_parser_unittest.cc",
     "win/scaling_util_unittest.cc",
     "win/screen_win_unittest.cc",
   ]
 
   deps = [
     ":display",
     ":test_support",
     "//base",
-    "//base/test:run_all_unittests",
     "//base/test:test_support",
+    "//mojo/edk/test:run_all_unittests",
     "//testing/gtest",
     "//ui/display/types",
     "//ui/display/util",
     "//ui/gfx:test_support",
     "//ui/gfx/geometry",
   ]
 
+  if (!is_ios) {
+    sources += [ "mojo/display_struct_traits_unittest.cc" ]
+
+    deps += [ "//ui/display/mojo:test_interfaces" ]
+  }
+
   if (is_chromeos) {
     deps += [ ":test_util" ]
   }
 
   if (use_aura) {
     sources -= [ "screen_unittest.cc" ]
   }
 
   if (is_android) {
     # Do not run display_change_notifier_unittest.cc on Android because it
     # does not compile display_observer.cc
     sources -= [ "display_change_notifier_unittest.cc" ]
   }
 
   if (is_chromeos && use_ozone) {
     sources -= [
       "chromeos/x11/display_util_x11_unittest.cc",
       "chromeos/x11/native_display_event_dispatcher_x11_unittest.cc",
     ]
   }
 }