ui: Cleanup class/struct forward declarations

ui/views/controls/scrollbar/native_scroll_bar_views.h

Index: ui/views/controls/scrollbar/native_scroll_bar_views.h
diff --git a/ui/views/controls/scrollbar/native_scroll_bar_views.h b/ui/views/controls/scrollbar/native_scroll_bar_views.h
deleted file mode 100644
index d09f60de07ddec6e9dbe738a7870da61dcd785bb..0000000000000000000000000000000000000000
--- a/ui/views/controls/scrollbar/native_scroll_bar_views.h
+++ /dev/null
@@ -1,78 +0,0 @@
-// 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_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_VIEWS_H_
-#define UI_VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_VIEWS_H_
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "ui/gfx/geometry/point.h"
-#include "ui/native_theme/native_theme.h"
-#include "ui/views/controls/button/button.h"
-#include "ui/views/controls/scrollbar/base_scroll_bar.h"
-#include "ui/views/controls/scrollbar/native_scroll_bar_wrapper.h"
-#include "ui/views/view.h"
-
-namespace gfx {
-class Canvas;
-}
-
-namespace views {
-
-class NativeScrollBar;
-
-// Views implementation for the scrollbar.
-class VIEWS_EXPORT NativeScrollBarViews : public BaseScrollBar,
-                                          public ButtonListener,
-                                          public NativeScrollBarWrapper {
- public:
-  static const char kViewClassName[];
-
-  // Creates new scrollbar, either horizontal or vertical.
-  explicit NativeScrollBarViews(NativeScrollBar* native_scroll_bar);
-  ~NativeScrollBarViews() override;
-
- private:
-  // View overrides:
-  void Layout() override;
-  void OnPaint(gfx::Canvas* canvas) override;
-  gfx::Size GetPreferredSize() const override;
-  const char* GetClassName() const override;
-
-  // ScrollBar overrides:
-  int GetLayoutSize() const override;
-
-  // BaseScrollBar overrides:
-  void ScrollToPosition(int position) override;
-  int GetScrollIncrement(bool is_page, bool is_positive) override;
-
-  // BaseButton::ButtonListener overrides:
-  void ButtonPressed(Button* sender, const ui::Event& event) override;
-
-  // NativeScrollBarWrapper overrides:
-  int GetPosition() const override;
-  View* GetView() override;
-  void Update(int viewport_size, int content_size, int current_pos) override;
-
-  // Returns the area for the track. This is the area of the scrollbar minus
-  // the size of the arrow buttons.
-  gfx::Rect GetTrackBounds() const override;
-
-  // The NativeScrollBar we are bound to.
-  NativeScrollBar* native_scroll_bar_;
-
-  // The scroll bar buttons (Up/Down, Left/Right).
-  Button* prev_button_;
-  Button* next_button_;
-
-  ui::NativeTheme::ExtraParams params_;
-  ui::NativeTheme::Part part_;
-  ui::NativeTheme::State state_;
-
-  DISALLOW_COPY_AND_ASSIGN(NativeScrollBarViews);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_VIEWS_H_