[DONT COMMIT] Revert of Mus: ws/ should not depend on surfaces/

services/ui/ws/test_server_window_delegate.cc

 // Copyright 2014 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/surfaces/display_compositor.h"
 #include "services/ui/ws/server_window.h"
 #include "services/ui/ws/test_server_window_delegate.h"
 
 namespace ui {
 
 namespace ws {
 
 TestServerWindowDelegate::TestServerWindowDelegate()
-    : root_window_(nullptr) {}
+    : root_window_(nullptr),
+      display_compositor_(
+          new DisplayCompositor(nullptr, nullptr, nullptr, nullptr)) {}
 
 TestServerWindowDelegate::~TestServerWindowDelegate() {}
 
 cc::mojom::DisplayCompositor* TestServerWindowDelegate::GetDisplayCompositor() {
-  return nullptr;
+  return display_compositor_.get();
 }
 
 ServerWindow* TestServerWindowDelegate::GetRootWindow(
     const ServerWindow* window) {
   return root_window_;
 }
 
 }  // namespace ws
 
 }  // namespace ui