Makes WindowTree take the AccessPolicy

components/mus/ws/window_tree_factory.cc

 // 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.
 
 #include "components/mus/ws/window_tree_factory.h"
 
 #include "components/mus/ws/connection_manager.h"
+#include "components/mus/ws/default_access_policy.h"
 #include "components/mus/ws/window_tree.h"
 #include "components/mus/ws/window_tree_binding.h"
 
 namespace mus {
 namespace ws {
 
 WindowTreeFactory::WindowTreeFactory(ConnectionManager* connection_manager,
                                      const UserId& user_id)
     : connection_manager_(connection_manager), user_id_(user_id) {}
 
 WindowTreeFactory::~WindowTreeFactory() {}
 
 void WindowTreeFactory::AddBinding(
     mojo::InterfaceRequest<mus::mojom::WindowTreeFactory> request) {
   binding_.AddBinding(this, std::move(request));
 }
 
 void WindowTreeFactory::CreateWindowTree(
     mojo::InterfaceRequest<mojom::WindowTree> tree_request,
     mojom::WindowTreeClientPtr client) {
   scoped_ptr<ws::WindowTree> service(
-      new ws::WindowTree(connection_manager_, user_id_, nullptr));
+      new ws::WindowTree(connection_manager_, user_id_, nullptr,
+                         make_scoped_ptr(new DefaultAccessPolicy)));
   scoped_ptr<ws::DefaultWindowTreeBinding> binding(
       new ws::DefaultWindowTreeBinding(service.get(), connection_manager_,
                                        std::move(tree_request),
                                        std::move(client)));
   connection_manager_->AddTree(std::move(service), std::move(binding), nullptr);
 }
 
 }  // namespace ws
 }  // namespace mus