Makes display roots be destroyed by client

services/ui/demo/mus_demo.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/demo/mus_demo.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/time/time.h"
 #include "services/shell/public/cpp/connector.h"
 #include "services/ui/demo/bitmap_uploader.h"
@@ skipping 112 matching lines @@
   // Initialize bitmap uploader for sending frames to MUS.
   uploader_.reset(new BitmapUploader(window_));
   uploader_->Init(gpu_service_.get());
 
   // Draw initial frame and start the timer to regularly draw frames.
   DrawFrame();
   timer_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(kFrameDelay),
                base::Bind(&MusDemo::DrawFrame, base::Unretained(this)));
 }
 
+void MusDemo::OnWmDisplayRemoved(ui::Window* window) {
+  window->Destroy();
+}
+
 void MusDemo::OnWmPerformMoveLoop(Window* window,
                                   mojom::MoveLoopSource source,
                                   const gfx::Point& cursor_location,
                                   const base::Callback<void(bool)>& on_done) {
   // Don't care
 }
 
 void MusDemo::OnWmCancelMoveLoop(Window* window) {}
 
 void MusDemo::AllocBitmap() {
@@ skipping 37 matching lines @@
       new std::vector<unsigned char>(addr, addr + bytes));
   bitmap_.unlockPixels();
 
   // Send frame to MUS via BitmapUploader.
   uploader_->SetBitmap(bounds.width(), bounds.height(), std::move(data),
                        BitmapUploader::BGRA);
 }
 
 }  // namespace demo
 }  // namespace ui