CHECK for re-addition of indirect objects

core/fpdfapi/parser/cpdf_indirect_object_holder.cpp

 // 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
 
 #include "core/fpdfapi/parser/cpdf_indirect_object_holder.h"
 
 #include "core/fpdfapi/parser/cpdf_object.h"
 #include "core/fpdfapi/parser/cpdf_parser.h"
@@ skipping 25 matching lines @@
   m_LastObjNum = std::max(m_LastObjNum, objnum);
   m_IndirectObjs[objnum].reset(pObj);
   return pObj;
 }
 
 CPDF_Object* CPDF_IndirectObjectHolder::ParseIndirectObject(uint32_t objnum) {
   return nullptr;
 }
 
 uint32_t CPDF_IndirectObjectHolder::AddIndirectObject(CPDF_Object* pObj) {
-  if (pObj->m_ObjNum)
-    return pObj->m_ObjNum;
-
+  CHECK(!pObj->m_ObjNum);
   m_LastObjNum++;
   m_IndirectObjs[m_LastObjNum].release();  // TODO(tsepez): stop this leak.
   m_IndirectObjs[m_LastObjNum].reset(pObj);
   pObj->m_ObjNum = m_LastObjNum;
   return m_LastObjNum;
 }
 
 bool CPDF_IndirectObjectHolder::ReplaceIndirectObjectIfHigherGeneration(
     uint32_t objnum,
     CPDF_Object* pObj) {
@@ skipping 12 matching lines @@
   return true;
 }
 
 void CPDF_IndirectObjectHolder::DeleteIndirectObject(uint32_t objnum) {
   CPDF_Object* pObj = GetIndirectObject(objnum);
   if (!pObj || pObj->GetObjNum() == CPDF_Object::kInvalidObjNum)
     return;
 
   m_IndirectObjs.erase(objnum);
 }