views: remove FocusableRoundedBorderMac

ui/views/controls/focusable_rounded_border_mac.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 UI_VIEWS_CONTROLS_FOCUSABLE_ROUNDED_BORDER_H_
-#define UI_VIEWS_CONTROLS_FOCUSABLE_ROUNDED_BORDER_H_
-
-#include "base/macros.h"
-#include "ui/views/controls/focusable_border.h"
-#include "ui/views/view.h"
-
-namespace views {
-
-// A Border that changes colors in accordance with the system color scheme when
-// the View it borders is focused.
-class FocusableRoundedBorder : public FocusableBorder {
- public:
-  FocusableRoundedBorder();
-  ~FocusableRoundedBorder() override;
-
-  // Border:
-  void Paint(const View& view, gfx::Canvas* canvas) override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(FocusableRoundedBorder);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_CONTROLS_FOCUSABLE_ROUNDED_BORDER_H_