Re-land "Make CPDF_IndirectObjectHolder use unique_ptr to objects""

core/fpdfapi/fpdf_parser/include/cpdf_object.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_PARSER_INCLUDE_CPDF_OBJECT_H_
 #define CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_OBJECT_H_
 
+#include <memory>
 #include <set>
 
 #include "core/fxcrt/include/fx_string.h"
 #include "core/fxcrt/include/fx_system.h"
 
 class CPDF_Array;
 class CPDF_Boolean;
 class CPDF_Dictionary;
 class CPDF_Name;
 class CPDF_Null;
@@ skipping 65 matching lines @@
   virtual const CPDF_String* AsString() const;
 
  protected:
   friend class CPDF_Array;
   friend class CPDF_Dictionary;
   friend class CPDF_Document;
   friend class CPDF_IndirectObjectHolder;
   friend class CPDF_Parser;
   friend class CPDF_Reference;
   friend class CPDF_Stream;
+  friend struct std::default_delete<CPDF_Object>;
 
   CPDF_Object() : m_ObjNum(0), m_GenNum(0) {}
   virtual ~CPDF_Object();
 
   CPDF_Object* CloneObjectNonCyclic(bool bDirect) const;
 
   // Create a deep copy of the object with the option to either
   // copy a reference object or directly copy the object it refers to
   // when |bDirect| is true.
   // Also check cyclic reference against |pVisited|, no copy if it is found.
@@ skipping 67 matching lines @@
 
 inline CPDF_Stream* ToStream(CPDF_Object* obj) {
   return obj ? obj->AsStream() : nullptr;
 }
 
 inline const CPDF_Stream* ToStream(const CPDF_Object* obj) {
   return obj ? obj->AsStream() : nullptr;
 }
 
 #endif  // CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_OBJECT_H_