Make CPDF_ClipPath have a CPDF_ClipPathData rather than inheriting

core/fpdfapi/fpdf_page/cpdf_clippathdata.h

-// Copyright 2016 PDFium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
-
-#ifndef CORE_FPDFAPI_FPDF_PAGE_CPDF_CLIPPATHDATA_H_
-#define CORE_FPDFAPI_FPDF_PAGE_CPDF_CLIPPATHDATA_H_
-
-#include <stdint.h>
-
-#include <memory>
-#include <utility>
-#include <vector>
-
-class CPDF_Path;
-class CPDF_TextObject;
-
-class CPDF_ClipPathData {
- public:
-  using PathAndTypeData = std::pair<CPDF_Path, uint8_t>;
-  CPDF_ClipPathData();
-  CPDF_ClipPathData(const CPDF_ClipPathData&);
-  ~CPDF_ClipPathData();
-
-  std::vector<PathAndTypeData> m_PathAndTypeList;
-  std::vector<std::unique_ptr<CPDF_TextObject>> m_TextList;
-};
-
-#endif  // CORE_FPDFAPI_FPDF_PAGE_CPDF_CLIPPATHDATA_H_