Return unique_ptr from CPDF_Object::Clone().

core/fpdfapi/parser/cpdf_number.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_PARSER_CPDF_NUMBER_H_
 #define CORE_FPDFAPI_PARSER_CPDF_NUMBER_H_
 
 #include "core/fpdfapi/parser/cpdf_object.h"
 #include "core/fxcrt/fx_string.h"
 #include "core/fxcrt/fx_system.h"
 
 class CPDF_Number : public CPDF_Object {
  public:
   CPDF_Number();
   explicit CPDF_Number(int value);
   explicit CPDF_Number(FX_FLOAT value);
   explicit CPDF_Number(const CFX_ByteStringC& str);
   ~CPDF_Number() override;
 
-  // CPDF_Object.
+  // CPDF_Object:
   Type GetType() const override;
-  CPDF_Object* Clone() const override;
+  std::unique_ptr<CPDF_Object> Clone() const override;
   CFX_ByteString GetString() const override;
   FX_FLOAT GetNumber() const override;
   int GetInteger() const override;
   void SetString(const CFX_ByteString& str) override;
   bool IsNumber() const override;
   CPDF_Number* AsNumber() override;
   const CPDF_Number* AsNumber() const override;
 
   bool IsInteger() const { return m_bInteger; }
 
  protected:
   bool m_bInteger;
   union {
     int m_Integer;
     FX_FLOAT m_Float;
   };
 };
 
 inline CPDF_Number* ToNumber(CPDF_Object* obj) {
   return obj ? obj->AsNumber() : nullptr;
 }
 
 inline const CPDF_Number* ToNumber(const CPDF_Object* obj) {
   return obj ? obj->AsNumber() : nullptr;
 }
 
 #endif  // CORE_FPDFAPI_PARSER_CPDF_NUMBER_H_