Remove WebScroll*

sky/engine/public/platform/WebScrollbarBehavior.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 WebScrollbarBehavior_h
-#define WebScrollbarBehavior_h
-
-namespace blink {
-
-struct WebPoint;
-struct WebRect;
-
-class WebScrollbarBehavior {
-public:
-    enum Button {
-        ButtonNone = -1,
-        ButtonLeft,
-        ButtonMiddle,
-        ButtonRight
-    };
-    virtual ~WebScrollbarBehavior() { }
-    virtual bool shouldCenterOnThumb(Button, bool shiftKeyPressed, bool altKeyPressed) { return false; }
-    virtual bool shouldSnapBackToDragOrigin(const WebPoint& eventPoint, const WebRect& scrollbarRect, bool isHorizontal) { return false; }
-};
-
-} // namespace blink
-
-#endif