Revert of chromeos: Makes mushrome use simplified display management

chrome/app/mash/embedded_services.cc

Index: chrome/app/mash/embedded_services.cc
diff --git a/chrome/app/mash/embedded_services.cc b/chrome/app/mash/embedded_services.cc
index 88f5152aa5fd36d5c32dbd3811331f2fb8c7487d..65ef4dae14b75839b9400443d0beecf285d40251 100644
--- a/chrome/app/mash/embedded_services.cc
+++ b/chrome/app/mash/embedded_services.cc
@@ -31,11 +31,8 @@
 std::unique_ptr<service_manager::Service> CreateEmbeddedMashService(
     const std::string& service_name) {
 #if defined(OS_CHROMEOS)
-  if (service_name == ash::mojom::kServiceName) {
-    const bool show_primary_host_on_connect = true;
-    return base::WrapUnique(
-        new ash::mus::WindowManagerApplication(show_primary_host_on_connect));
-  }
+  if (service_name == ash::mojom::kServiceName)
+    return base::MakeUnique<ash::mus::WindowManagerApplication>();
   if (service_name == "accessibility_autoclick")
     return base::MakeUnique<ash::autoclick::AutoclickApplication>();
   if (service_name == "touch_hud")