Add FakeDisplayDelegate for off device usage.

services/ui/display/platform_screen_ozone.h

Index: services/ui/display/platform_screen_ozone.h
diff --git a/services/ui/display/platform_screen_ozone.h b/services/ui/display/platform_screen_ozone.h
index 521ead33aa394f005efe4fc06a817f032b788894..bb7bfab7fd5b8cf0bc89d9a70b728ecced7761cc 100644
--- a/services/ui/display/platform_screen_ozone.h
+++ b/services/ui/display/platform_screen_ozone.h
@@ -19,6 +19,7 @@
 #include "services/ui/public/interfaces/display/display_controller.mojom.h"
 #include "ui/display/chromeos/display_configurator.h"
 #include "ui/display/display.h"
+#include "ui/display/types/virtual_display_controller.h"
 
 namespace display {
 
@@ -102,6 +103,10 @@ class PlatformScreenOzone
   ui::DisplayConfigurator display_configurator_;
   PlatformScreenDelegate* delegate_ = nullptr;
 
+  // If not null it provides a way to modify the virtual display state for
+  // running off device.
+  VirtualDisplayController* virtual_display_controller_ = nullptr;
+
   // TODO(kylechar): These values can/should be replaced by DisplayLayout.
   int64_t primary_display_id_ = display::Display::kInvalidDisplayID;
   std::vector<DisplayInfo> cached_displays_;