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

core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp

Index: core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp
diff --git a/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp b/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp
index dc639feb1a4b28915b5916d23e4fb68523e82c50..800e34b3d1eb62f3a1de4c4fc27c6a5727bc702a 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp
@@ -11,15 +11,12 @@
 
 CPDF_IndirectObjectHolder::CPDF_IndirectObjectHolder() : m_LastObjNum(0) {}
 
-CPDF_IndirectObjectHolder::~CPDF_IndirectObjectHolder() {
-  for (const auto& pair : m_IndirectObjs)
-    delete pair.second;
-}
+CPDF_IndirectObjectHolder::~CPDF_IndirectObjectHolder() {}
 
 CPDF_Object* CPDF_IndirectObjectHolder::GetIndirectObject(
     uint32_t objnum) const {
   auto it = m_IndirectObjs.find(objnum);
-  return it != m_IndirectObjs.end() ? it->second : nullptr;
+  return it != m_IndirectObjs.end() ? it->second.get() : nullptr;
 }
 
 CPDF_Object* CPDF_IndirectObjectHolder::GetOrParseIndirectObject(
@@ -37,10 +34,7 @@ CPDF_Object* CPDF_IndirectObjectHolder::GetOrParseIndirectObject(
 
   pObj->m_ObjNum = objnum;
   m_LastObjNum = std::max(m_LastObjNum, objnum);
-  if (m_IndirectObjs[objnum])
-    delete m_IndirectObjs[objnum];
-
-  m_IndirectObjs[objnum] = pObj;
+  m_IndirectObjs[objnum].reset(pObj);
   return pObj;
 }
 
@@ -53,7 +47,7 @@ uint32_t CPDF_IndirectObjectHolder::AddIndirectObject(CPDF_Object* pObj) {
     return pObj->m_ObjNum;
 
   m_LastObjNum++;
-  m_IndirectObjs[m_LastObjNum] = pObj;
+  m_IndirectObjs[m_LastObjNum].reset(pObj);
   pObj->m_ObjNum = m_LastObjNum;
   return m_LastObjNum;
 }
@@ -65,15 +59,12 @@ bool CPDF_IndirectObjectHolder::ReplaceIndirectObjectIfHigherGeneration(
     return false;
 
   CPDF_Object* pOldObj = GetIndirectObject(objnum);
-  if (pOldObj) {
-    if (pObj->GetGenNum() <= pOldObj->GetGenNum()) {
-      delete pObj;
-      return false;
-    }
-    delete pOldObj;
+  if (pOldObj && pObj->GetGenNum() <= pOldObj->GetGenNum()) {
+    delete pObj;
+    return false;
   }
   pObj->m_ObjNum = objnum;
-  m_IndirectObjs[objnum] = pObj;
+  m_IndirectObjs[objnum].reset(pObj);
   m_LastObjNum = std::max(m_LastObjNum, objnum);
   return true;
 }
@@ -83,6 +74,5 @@ void CPDF_IndirectObjectHolder::ReleaseIndirectObject(uint32_t objnum) {
   if (!pObj || pObj->GetObjNum() == CPDF_Object::kInvalidObjNum)
     return;
 
-  delete pObj;
   m_IndirectObjs.erase(objnum);
 }