Allow parallel creation of windows

services/ui/demo/mus_demo_external.h

 // 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.
 
 #ifndef SERVICES_UI_DEMO_MUS_DEMO_EXTERNAL_H_
 #define SERVICES_UI_DEMO_MUS_DEMO_EXTERNAL_H_
 
 #include <memory>
 #include <vector>
 
 #include "services/ui/demo/mus_demo.h"
 #include "services/ui/public/interfaces/window_tree_host.mojom.h"
 
 namespace ui {
 namespace demo {
 
 // MusDemoExternal demonstrates Mus operating in "external" mode: A new platform
 // window (and hence acceleratedWidget) is created for each aura window.
 class MusDemoExternal : public MusDemo {
  public:
   MusDemoExternal();
   ~MusDemoExternal() final;
 
  private:
-  void OpenNewWindow();
+  void OpenNewWindow(size_t window_count);

[fwang, 2017/03/16 08:59:49]

Maybe this can be window_index?

[msisov(use msisov igalia.com), 2017/03/16 09:21:32]

Done.

 
   // ui::demo::MusDemo:
   void OnStartImpl() final;
   std::unique_ptr<aura::WindowTreeClient> CreateWindowTreeClient() final;
 
   // aura::WindowTreeClientDelegate:
-  void OnEmbed(std::unique_ptr<aura::WindowTreeHostMus> window_tree_host) final;
+  void OnEmbedRootReady(aura::WindowTreeHostMus* window_tree_host) final;
   void OnEmbedRootDestroyed(aura::WindowTreeHostMus* window_tree_host) final;
 
-  size_t initialized_windows_count_ = 0;
-
   size_t number_of_windows_ = 1;
 
   DISALLOW_COPY_AND_ASSIGN(MusDemoExternal);
 };
 
 }  // namespace demo
 }  // namespace ui
 
 #endif  // SERVICES_UI_DEMO_MUS_DEMO_EXTERNAL_H_