ui: Cleanup class/struct forward declarations

ui/views/controls/scrollbar/native_scroll_bar_wrapper.h

Index: ui/views/controls/scrollbar/native_scroll_bar_wrapper.h
diff --git a/ui/views/controls/scrollbar/native_scroll_bar_wrapper.h b/ui/views/controls/scrollbar/native_scroll_bar_wrapper.h
deleted file mode 100644
index 6f4e45aee88fdb59e4496abb237105f4c6a5113a..0000000000000000000000000000000000000000
--- a/ui/views/controls/scrollbar/native_scroll_bar_wrapper.h
+++ /dev/null
@@ -1,45 +0,0 @@
-// 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_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WRAPPER_H_
-#define UI_VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WRAPPER_H_
-
-#include "ui/views/views_export.h"
-
-namespace ui {
-class NativeTheme;
-}
-
-namespace views {
-
-class NativeScrollBar;
-class View;
-
-// A specialization of NativeControlWrapper that hosts a platform-native
-// scroll bar.
-class VIEWS_EXPORT NativeScrollBarWrapper {
- public:
-  virtual ~NativeScrollBarWrapper() {}
-
-  // Updates the scroll bar appearance given a viewport size, content size and
-  // current position.
-  virtual void Update(int viewport_size, int content_size, int current_pos) = 0;
-
-  // Retrieves the views::View that hosts the native control.
-  virtual View* GetView() = 0;
-
-  // Returns the position of the scrollbar.
-  virtual int GetPosition() const = 0;
-
-  // Creates an appropriate NativeScrollBarWrapper for the platform.
-  static NativeScrollBarWrapper* CreateWrapper(NativeScrollBar* button);
-
-  // Returns the system sizes of vertical/horizontal scroll bars.
-  static int GetVerticalScrollBarWidth(const ui::NativeTheme* theme);
-  static int GetHorizontalScrollBarHeight(const ui::NativeTheme* theme);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WRAPPER_H_