Adding a Views scrollbar implementation.

views/controls/scrollbar/native_scroll_bar_views.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 VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_VIEWS_H_
+#define VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_VIEWS_H_
+#pragma once
+
+#include "ui/gfx/native_theme.h"
+#include "ui/gfx/point.h"
+#include "views/controls/button/button.h"
+#include "views/controls/scrollbar/base_scroll_bar.h"
+#include "views/controls/scrollbar/native_scroll_bar_wrapper.h"
+#include "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:
+  // Creates new scrollbar, either horizontal or vertical.
+  explicit NativeScrollBarViews(NativeScrollBar* native_scroll_bar);
+  virtual ~NativeScrollBarViews();
+
+ private:
+  // View overrides:
+  virtual void Layout();
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
+  virtual gfx::Size GetPreferredSize();
+
+  // ScrollBar overrides:
+  virtual int GetLayoutSize() const OVERRIDE;
+
+  // BaseScrollBar overrides:
+  virtual void ScrollToPosition(int position);
+  virtual int GetScrollIncrement(bool is_page, bool is_positive);
+
+  // BaseButton::ButtonListener overrides:
+  virtual void ButtonPressed(Button* sender,
+                             const views::Event& event) OVERRIDE;
+
+  // NativeScrollBarWrapper overrides:
+  virtual int GetPosition() const;
+  virtual View* GetView();
+  virtual void Update(int viewport_size, int content_size, int current_pos);
+
+  // Returns the area for the track. This is the area of the scrollbar minus
+  // the size of the arrow buttons.
+  virtual 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_;
+
+  gfx::NativeTheme::ExtraParams params_;
+  gfx::NativeTheme::Part part_;
+  gfx::NativeTheme::State state_;
+
+  DISALLOW_COPY_AND_ASSIGN(NativeScrollBarViews);
+};
+
+}  // namespace views
+
+#endif  // VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_VIEWS_H_
+