Demo UI made with a help of WUG toolkit (DO NOT SEND TO CQ).

chrome/browser/ui/webui/demo_ui/reuse/reuse_demo.h

+// Copyright 2015 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 CHROME_BROWSER_UI_WEBUI_DEMO_UI_REUSE_REUSE_DEMO_H_
+#define CHROME_BROWSER_UI_WEBUI_DEMO_UI_REUSE_REUSE_DEMO_H_
+
+#include "base/macros.h"
+#include "chrome/browser/ui/webui/demo_ui/events/events_demo.h"
+#include "components/demo_ui/reuse/reuse_demo_view_model.h"
+
+class ReuseDemo : public gen::ReuseDemoViewModel, public EventsDemo::Observer {
+ public:
+  static void Register();
+
+  ReuseDemo();
+  ~ReuseDemo() override;
+
+  // Overridden from webui_generator::ViewModel:
+  void OnAfterChildrenReady() override;
+
+  // Overridden from gen::ReuseDemoViewModel:
+  EventsDemo* GetLeftEvents() const override;
+  EventsDemo* GetRightEvents() const override;
+
+ private:
+  // Overridden from EventsDemo::Observer:
+  void EventsCounterChanged() override;
+
+  DISALLOW_COPY_AND_ASSIGN(ReuseDemo);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_DEMO_UI_REUSE_REUSE_DEMO_H_