Makes it possible for clients to directly create WindowTreeHostMus

ui/views/mus/mus_client.h

 // 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.
 
 #ifndef UI_VIEWS_MUS_MUS_CLIENT_INIT_H_
 #define UI_VIEWS_MUS_MUS_CLIENT_INIT_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 58 matching lines @@
   service_manager::Connector* connector() { return connector_; }
 
  private:
   NativeWidget* CreateNativeWidget(const Widget::InitParams& init_params,
                                    internal::NativeWidgetDelegate* delegate);
 
   // Creates aura::WindowPortMus.
   std::unique_ptr<aura::WindowPort> CreateWindowPort(aura::Window* window);
 
   // aura::WindowTreeClientDelegate:
-  void OnEmbed(aura::Window* root) override;
+  void OnEmbed(
+      std::unique_ptr<aura::WindowTreeHostMus> window_tree_host) override;
   void OnLostConnection(aura::WindowTreeClient* client) override;
   void OnEmbedRootDestroyed(aura::Window* root) override;
   void OnPointerEventObserved(const ui::PointerEvent& event,
                               aura::Window* target) override;
   aura::client::FocusClient* GetFocusClient() override;
   aura::client::CaptureClient* GetCaptureClient() override;
   aura::PropertyConverter* GetPropertyConverter() override;
 
   // ScreenMusDelegate:
   void OnWindowManagerFrameValuesChanged() override;
@@ skipping 21 matching lines @@
   std::unique_ptr<ui::GpuService> gpu_service_;
 
   std::unique_ptr<SurfaceContextFactory> compositor_context_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MusClient);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_MUS_MUS_CLIENT_INIT_H_