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

services/ui/ws/test_server_window_delegate.cc

Index: services/ui/ws/test_server_window_delegate.cc
diff --git a/services/ui/ws/test_server_window_delegate.cc b/services/ui/ws/test_server_window_delegate.cc
index a19ee6f6875aec285dee38336e031c177d9b1777..818879fd921af72366f0d27fbed1fc0b12639dc4 100644
--- a/services/ui/ws/test_server_window_delegate.cc
+++ b/services/ui/ws/test_server_window_delegate.cc
@@ -2,6 +2,7 @@
 // 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"
 
@@ -10,12 +11,14 @@
 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(