Revert of Mustash: Ensure surfaces submitted to Mus by WM and embedders contain Surfaces with embeded content.

services/ui/ws/platform_display_default.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 SERVICES_UI_WS_PLATFORM_DISPLAY_DEFAULT_H_
 #define SERVICES_UI_WS_PLATFORM_DISPLAY_DEFAULT_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 50 matching lines @@
   void OnCloseRequest() override;
   void OnClosed() override;
   void OnWindowStateChanged(ui::PlatformWindowState new_state) override;
   void OnLostCapture() override;
   void OnAcceleratedWidgetAvailable(gfx::AcceleratedWidget widget,
                                     float device_scale_factor) override;
   void OnAcceleratedWidgetDestroyed() override;
   void OnActivationChanged(bool active) override;
 
   // FrameGeneratorDelegate:
-  ServerWindow* GetActiveRootWindow() override;
   bool IsInHighContrastMode() override;
 
   const int64_t display_id_;
 
 #if !defined(OS_ANDROID)
   std::unique_ptr<ui::ImageCursors> image_cursors_;
 #endif
 
   PlatformDisplayDelegate* delegate_ = nullptr;
   std::unique_ptr<FrameGenerator> frame_generator_;
 
   display::ViewportMetrics metrics_;
   std::unique_ptr<ui::PlatformWindow> platform_window_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformDisplayDefault);
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_PLATFORM_DISPLAY_DEFAULT_H_