Implement a MusBrowserFrame.

ui/views/mus/native_widget_mus.h

 // Copyright 2015 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_NATIVE_WIDGET_MUS_H_
 #define UI_VIEWS_MUS_NATIVE_WIDGET_MUS_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "components/mus/public/interfaces/window_manager.mojom.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/platform_window/platform_window_delegate.h"
 #include "ui/views/widget/native_widget_private.h"
 
 namespace aura {
 namespace client {
 class DefaultCaptureClient;
+class WindowTreeClient;
 }
 class Window;
 }
 
 namespace mojo {
 class Shell;
 }
 
 namespace mus {
 class Window;
@@ skipping 158 matching lines @@
   internal::NativeWidgetDelegate* native_widget_delegate_;
 
   const mus::mojom::SurfaceType surface_type_;
   ui::PlatformWindowState show_state_before_fullscreen_;
 
   // Aura configuration.
   scoped_ptr<WindowTreeHostMus> window_tree_host_;
   aura::Window* content_;
   scoped_ptr<wm::FocusController> focus_client_;
   scoped_ptr<aura::client::DefaultCaptureClient> capture_client_;
+  scoped_ptr<aura::client::WindowTreeClient> window_tree_client_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeWidgetMus);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_MUS_NATIVE_WIDGET_MUS_H_