It is time.

ui/views/examples/checkbox_example.h

-// Copyright (c) 2012 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 UI_VIEWS_EXAMPLES_CHECKBOX_EXAMPLE_H_
-#define UI_VIEWS_EXAMPLES_CHECKBOX_EXAMPLE_H_
-
-#include "base/macros.h"
-#include "ui/views/controls/button/button.h"
-#include "ui/views/examples/example_base.h"
-
-namespace views {
-class Checkbox;
-
-namespace examples {
-
-// CheckboxExample exercises a Checkbox control.
-class VIEWS_EXAMPLES_EXPORT CheckboxExample : public ExampleBase,
-                                              public ButtonListener {
- public:
-  CheckboxExample();
-  virtual ~CheckboxExample();
-
-  // ExampleBase:
-  virtual void CreateExampleView(View* container) override;
-
- private:
-  // ButtonListener:
-  virtual void ButtonPressed(Button* sender, const ui::Event& event) override;
-
-  // The only control in this test.
-  Checkbox* button_;
-
-  int count_;
-
-  DISALLOW_COPY_AND_ASSIGN(CheckboxExample);
-};
-
-}  // namespace examples
-}  // namespace views
-
-#endif  // UI_VIEWS_EXAMPLES_CHECKBOX_EXAMPLE_H_