Move RenderBoxClipper to core/paint/

Source/core/rendering/RenderBoxClipper.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 RenderBoxClipper_h
-#define RenderBoxClipper_h
-
-#include "core/rendering/PaintPhase.h"
-#include "platform/geometry/LayoutPoint.h"
-
-namespace blink {
-
-class RenderBox;
-struct PaintInfo;
-
-enum ContentsClipBehavior { ForceContentsClip, SkipContentsClipIfPossible };
-
-class RenderBoxClipper {
-public:
-    RenderBoxClipper(RenderBox&, PaintInfo&, const LayoutPoint& accumulatedOffset, ContentsClipBehavior);
-    ~RenderBoxClipper();
-
-    bool pushedClip() { return m_pushedClip; }
-private:
-    bool m_pushedClip;
-    LayoutPoint m_accumulatedOffset;
-    PaintInfo& m_paintInfo;
-    PaintPhase m_originalPhase;
-    RenderBox& m_box;
-};
-
-} // namespace blink
-
-#endif // RenderBoxClipper_h