Use more unique_ptrs in CPDF_Image.

core/fpdfapi/page/cpdf_pathobject.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_PAGE_CPDF_PATHOBJECT_H_
 #define CORE_FPDFAPI_PAGE_CPDF_PATHOBJECT_H_
 
 #include "core/fpdfapi/page/cpdf_pageobject.h"
 #include "core/fpdfapi/page/cpdf_path.h"
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_system.h"
 
 class CPDF_PathObject : public CPDF_PageObject {
  public:
   CPDF_PathObject();
   ~CPDF_PathObject() override;
 
   // CPDF_PageObject
-  CPDF_PathObject* Clone() const override;
   Type GetType() const override;
   void Transform(const CFX_Matrix& maxtrix) override;
   bool IsPath() const override;
   CPDF_PathObject* AsPath() override;
   const CPDF_PathObject* AsPath() const override;
 
   void CalcBoundingBox();
 
   CPDF_Path m_Path;
   int m_FillType;
   bool m_bStroke;
   CFX_Matrix m_Matrix;
 };
 
 #endif  // CORE_FPDFAPI_PAGE_CPDF_PATHOBJECT_H_