Adds ability for WindowManager to create display roots

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index 6609d5390926a9659bd315cbf384311c78ab7ec9..e5a7c9276243d0764ed071127b8670709cb2b0fb 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -278,14 +278,16 @@ void WindowTreeClient::ConnectViaWindowTreeFactory() {
   SetWindowTree(std::move(window_tree));
 }
 
-void WindowTreeClient::ConnectAsWindowManager() {
+void WindowTreeClient::ConnectAsWindowManager(
+    bool automatically_create_display_roots) {
   DCHECK(window_manager_delegate_);
 
   ui::mojom::WindowManagerWindowTreeFactoryPtr factory;
   connector_->BindInterface(ui::mojom::kServiceName, &factory);
   ui::mojom::WindowTreePtr window_tree;
   factory->CreateWindowTree(MakeRequest(&window_tree),
-                            binding_.CreateInterfacePtrAndBind());
+                            binding_.CreateInterfacePtrAndBind(),
+                            automatically_create_display_roots);
   SetWindowTree(std::move(window_tree));
 }