It is time.

ui/views/examples/widget_example.h

-// Copyright (c) 2011 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_WIDGET_EXAMPLE_H_
-#define UI_VIEWS_EXAMPLES_WIDGET_EXAMPLE_H_
-
-#include <string>
-
-#include "base/macros.h"
-#include "ui/views/controls/button/button.h"
-#include "ui/views/examples/example_base.h"
-#include "ui/views/widget/widget.h"
-
-namespace views {
-namespace examples {
-
-// WidgetExample demonstrates how to create a popup widget.
-class VIEWS_EXAMPLES_EXPORT WidgetExample : public ExampleBase,
-                                            public ButtonListener {
- public:
-  WidgetExample();
-  virtual ~WidgetExample();
-
-  // ExampleBase:
-  virtual void CreateExampleView(View* container) override;
-
- private:
-  // Button tags used to identify various commands.
-  enum Command {
-    POPUP,        // Show a popup widget.
-    DIALOG,       // Show a dialog widget.
-    CHILD,        // Show a child widget.
-    CLOSE_WIDGET, // Close the sender button's widget.
-  };
-
-  // Construct a button with the specified |label| and |tag| in |container|.
-  void BuildButton(View* container, const std::string& label, int tag);
-
-  // Construct a Widget for |sender|, initialize with |params|, and call Show().
-  void ShowWidget(View* sender, Widget::InitParams params);
-
-  // ButtonListener:
-  virtual void ButtonPressed(Button* sender, const ui::Event& event) override;
-
-  DISALLOW_COPY_AND_ASSIGN(WidgetExample);
-};
-
-}  // namespace examples
-}  // namespace views
-
-#endif  // UI_VIEWS_EXAMPLES_WIDGET_EXAMPLE_H_