Add PlatformScreenDelegate and start implementation.

services/ui/ws/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")
 import("//services/shell/public/cpp/service.gni")
 import("//services/shell/public/service_manifest.gni")
 
 static_library("lib") {
   sources = [
     "accelerator.cc",
     "accelerator.h",
     "access_policy.h",
     "access_policy_delegate.h",
     "accessibility_manager.cc",
     "accessibility_manager.h",
     "animation_runner.cc",
     "animation_runner.h",
     "animation_runner_observer.h",
     "default_access_policy.cc",
     "default_access_policy.h",
     "display.cc",
     "display.h",
     "display_binding.cc",
     "display_binding.h",
     "display_manager.cc",
     "display_manager.h",
-    "display_manager_delegate.h",
     "event_dispatcher.cc",
     "event_dispatcher.h",
     "event_dispatcher_delegate.h",
     "event_matcher.cc",
     "event_matcher.h",
     "focus_controller.cc",
     "focus_controller.h",
     "focus_controller_delegate.h",
     "focus_controller_observer.h",
     "frame_generator.cc",
@@ skipping 23 matching lines @@
     "server_window_surface.h",
     "server_window_surface_manager.cc",
     "server_window_surface_manager.h",
     "server_window_tracker.h",
     "touch_controller.cc",
     "touch_controller.h",
     "user_activity_monitor.cc",
     "user_activity_monitor.h",
     "user_display_manager.cc",
     "user_display_manager.h",
+    "user_display_manager_delegate.h",
     "user_id.h",
     "user_id_tracker.cc",
     "user_id_tracker.h",
     "user_id_tracker_observer.h",
     "window_coordinate_conversions.cc",
     "window_coordinate_conversions.h",
     "window_finder.cc",
     "window_finder.h",
     "window_manager_access_policy.cc",
     "window_manager_access_policy.h",
@@ skipping 167 matching lines @@
 
   data_deps = [
     ":mus_ws_unittests_app_manifest",
   ]
 }
 
 service_manifest("mus_ws_unittests_app_manifest") {
   name = "mus_ws_unittests_app"
   source = "mus_ws_unittests_app_manifest.json"
 }