Adding a Views scrollbar implementation.

views/controls/scrollbar/base_scroll_bar_button.h

Index: views/controls/scrollbar/base_scroll_bar_button.h
diff --git a/views/controls/scrollbar/base_scroll_bar_button.h b/views/controls/scrollbar/base_scroll_bar_button.h
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+++ b/views/controls/scrollbar/base_scroll_bar_button.h
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+// 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_BASE_SCROLL_BAR_BUTTON_H_
+#define VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_BUTTON_H_
+#pragma once
+
+#include "views/controls/button/custom_button.h"
+
+#include "views/repeat_controller.h"
+
+#if defined(OS_LINUX)
+#include "ui/gfx/screen.h"
+#endif
+
+namespace views {
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// ScrollBarButton
+//
+//  A button that activates on mouse pressed rather than released, and that
+//  continues to fire the clicked action as the mouse button remains pressed
+//  down on the button.
+//
+///////////////////////////////////////////////////////////////////////////////
+class VIEWS_EXPORT BaseScrollBarButton : public CustomButton {
+ public:
+  explicit BaseScrollBarButton(ButtonListener* listener);
+  virtual ~BaseScrollBarButton();
+
+ protected:
+  virtual bool OnMousePressed(const MouseEvent& event) OVERRIDE;
+  virtual void OnMouseReleased(const MouseEvent& event) OVERRIDE;
+  virtual void OnMouseCaptureLost() OVERRIDE;
+
+ private:
+  void RepeaterNotifyClick();
+
+  // The repeat controller that we use to repeatedly click the button when the
+  // mouse button is down.
+  RepeatController repeater_;
+
+  DISALLOW_COPY_AND_ASSIGN(BaseScrollBarButton);
+};
+
+}  // namespace views
+
+#endif  // VIEWS_CONTROLS_SCROLLBAR_BASE_SCROLL_BAR_BUTTON_H_