Refactoring button field and its type

content/renderer/webscrollbarbehavior_impl_gtkoraura.h

 // Copyright 2014 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 CONTENT_RENDERER_WEBSCROLLBARBEHAVIOR_IMPL_GTKORAURA_H_
 #define CONTENT_RENDERER_WEBSCROLLBARBEHAVIOR_IMPL_GTKORAURA_H_
 
 #include "third_party/WebKit/public/platform/WebScrollbarBehavior.h"
 
 namespace content {
 
 class WebScrollbarBehaviorImpl : public blink::WebScrollbarBehavior {
  public:
-  bool shouldCenterOnThumb(blink::WebScrollbarBehavior::Button mouseButton,
+  bool shouldCenterOnThumb(blink::WebPointerProperties::Button mouseButton,
                            bool shiftKeyPressed,
                            bool altKeyPressed) override;
   bool shouldSnapBackToDragOrigin(const blink::WebPoint& eventPoint,
                                   const blink::WebRect& scrollbarRect,
                                   bool isHorizontal) override;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_WEBSCROLLBARBEHAVIOR_IMPL_GTKORAURA_H_