Make mus_demo_unittests work with multiple root windows

services/ui/ws/window_server_test_impl.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_WINDOW_SERVER_TEST_IMPL_H_
 #define SERVICES_UI_WS_WINDOW_SERVER_TEST_IMPL_H_
 
+#include <map>
+
 #include "services/ui/public/interfaces/window_server_test.mojom.h"
 
 namespace ui {
 namespace ws {
 
 class ServerWindow;
 class WindowServer;
 
 class WindowServerTestImpl : public mojom::WindowServerTest {
  public:
   explicit WindowServerTestImpl(WindowServer* server);
   ~WindowServerTestImpl() override;
 
  private:
   void OnWindowPaint(const std::string& name,
-                     const EnsureClientHasDrawnWindowCallback& cb,
+                     const EnsureClientHasDrawnRootWindowsCallback& cb,
                      ServerWindow* window);
 
   // mojom::WindowServerTest:
-  void EnsureClientHasDrawnWindow(
+  void EnsureClientHasDrawnRootWindows(
       const std::string& client_name,
-      const EnsureClientHasDrawnWindowCallback& callback) override;
+      const EnsureClientHasDrawnRootWindowsCallback& callback) override;
 
   WindowServer* window_server_;
+  std::map<std::string, unsigned> painted_window_roots_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowServerTestImpl);
 };
 
 }  // namespace ws
 }  // namespace ui
 
 #endif  // SERVICES_UI_WS_WINDOW_SERVER_TEST_IMPL_H_