Stub out ScreenManagerOzoneExternal

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",
     "screen_manager.h",
     "screen_manager_delegate.h",
     "viewport_metrics.cc",
     "viewport_metrics.h",
   ]
 
   deps = [
     "//base",
     "//services/service_manager/public/cpp",
     "//ui/display",
     "//ui/gfx",
   ]
 
-  if (use_ozone && is_chromeos) {
-    sources += [
-      "screen_manager_ozone_internal.cc",
-      "screen_manager_ozone_internal.h",
-    ]
+  if (use_ozone) {
+    if (is_chromeos) {
+      sources += [
+        "screen_manager_ozone_internal.cc",
+        "screen_manager_ozone_internal.h",
+      ]
 
-    deps += [
-      "//chromeos",
-      "//services/ui/public/interfaces/display",
-      "//skia",
-      "//ui/display/manager",
-      "//ui/ozone",
-    ]
+      deps += [
+        "//chromeos",
+        "//services/ui/public/interfaces/display",
+        "//skia",
+        "//ui/display/manager",
+        "//ui/ozone",
+      ]
+    } else {
+      sources += [
+        "screen_manager_ozone_external.cc",
+        "screen_manager_ozone_external.h",
+      ]
+    }
   } else {
     sources += [
       "screen_manager_stub_internal.cc",
       "screen_manager_stub_internal.h",
     ]
   }
 }
 
 if (use_ozone && is_chromeos) {
   test("display_service_unittests") {
@@ skipping 15 matching lines @@
       "//ui/gfx",
       "//ui/gfx:test_support",
       "//ui/ozone",
     ]
 
     data_deps = [
       "//ui/resources:ui_test_pak_data",
     ]
   }
 }