Removing example code related to deprecated NativeWidgetViews.

ui/views/examples/native_widget_views_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_NATIVE_WIDGET_VIEWS_EXAMPLE_H_
-#define UI_VIEWS_EXAMPLES_NATIVE_WIDGET_VIEWS_EXAMPLE_H_
-#pragma once
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "ui/views/examples/example_base.h"
-
-namespace examples {
-
-class NativeWidgetViewsExample : public ExampleBase {
- public:
-  explicit NativeWidgetViewsExample(ExamplesMain* main);
-  virtual ~NativeWidgetViewsExample();
-
-  // Overridden from ExampleBase:
-  virtual void CreateExampleView(views::View* container) OVERRIDE;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(NativeWidgetViewsExample);
-};
-
-}  // namespace examples
-
-#endif  // UI_VIEWS_EXAMPLES_NATIVE_WIDGET_VIEWS_EXAMPLE_H_