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

services/ui/ws/platform_display_default.cc

 // 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.
 
 #include "services/ui/ws/platform_display_default.h"
 
 #include "gpu/ipc/client/gpu_channel_host.h"
 #include "services/ui/display/screen_manager.h"
 #include "services/ui/ws/platform_display_init_params.h"
 #include "services/ui/ws/server_window.h"
@@ skipping 226 matching lines @@
   delegate_->OnAcceleratedWidgetAvailable();
   frame_generator_->OnAcceleratedWidgetAvailable(widget);
 }
 
 void PlatformDisplayDefault::OnAcceleratedWidgetDestroyed() {
   NOTREACHED();
 }
 
 void PlatformDisplayDefault::OnActivationChanged(bool active) {}
 
+ServerWindow* PlatformDisplayDefault::GetActiveRootWindow() {
+  return delegate_->GetActiveRootWindow();
+}
+
 bool PlatformDisplayDefault::IsInHighContrastMode() {
   return delegate_ ? delegate_->IsInHighContrastMode() : false;
 }
 
 }  // namespace ws
 }  // namespace ui