c++ / mojo changes for 'external window mode'

services/ui/ws/window_tree_host_factory_registrar.cc

+// Copyright 2017 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 "services/ui/ws/window_tree_host_factory_registrar.h"
+
+#include "services/ui/ws/default_access_policy.h"
+#include "services/ui/ws/window_server.h"
+#include "services/ui/ws/window_tree.h"
+#include "services/ui/ws/window_tree_host_factory.h"
+
+namespace ui {
+namespace ws {
+
+WindowTreeHostFactoryRegistrar::WindowTreeHostFactoryRegistrar(
+    WindowServer* window_server,
+    const UserId& user_id)
+    : window_server_(window_server), user_id_(user_id) {}
+
+WindowTreeHostFactoryRegistrar::~WindowTreeHostFactoryRegistrar() {}
+
+void WindowTreeHostFactoryRegistrar::Register(
+    mojom::WindowTreeHostFactoryRequest host_factory_request,
+    mojom::WindowTreeRequest tree_request,
+    mojom::WindowTreeClientPtr tree_client) {
+  std::unique_ptr<WindowTreeHostFactory> host_factory(
+      new WindowTreeHostFactory(window_server_, user_id_));
+
+  host_factory->AddBinding(std::move(host_factory_request));
+
+  std::unique_ptr<ws::WindowTree> tree(
+      new ws::WindowTree(window_server_, user_id_, nullptr /*ServerWindow*/,
+                         base::WrapUnique(new DefaultAccessPolicy)));
+
+  std::unique_ptr<ws::DefaultWindowTreeBinding> tree_binding(
+      new ws::DefaultWindowTreeBinding(tree.get(), window_server_,
+                                       std::move(tree_request),
+                                       std::move(tree_client)));
+
+  // Pass nullptr as mojom::WindowTreePtr (3rd parameter), because in external
+  // window mode, the WindowTreePtr is created on the aura/WindowTreeClient
+  // side.
+  //
+  // NOTE: This call to ::AddTree calls ::Init. However, it will not trigger a
+  // ::OnEmbed call because the WindowTree instance was created above passing
+  // 'nullptr' as the ServerWindow, hence there is no 'root' yet.
+  window_server_->AddTree(std::move(tree), std::move(tree_binding),
+                          nullptr /*mojom::WindowTreePtr*/);
+
+  window_server_->set_window_tree_host_factory(std::move(host_factory));
+}
+
+}  // namespace ws
+}  // namespace ui