Move CPDF_Reference::SafeGetDirect() out of the header.

core/fpdfapi/fpdf_parser/cpdf_reference.cpp

Index: core/fpdfapi/fpdf_parser/cpdf_reference.cpp
diff --git a/core/fpdfapi/fpdf_parser/cpdf_reference.cpp b/core/fpdfapi/fpdf_parser/cpdf_reference.cpp
index 06625a96ea84008d21674aec9c4ef7115d282990..4f826dc86c137cd6f931ef37380b5df6a1acf68e 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_reference.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_reference.cpp
@@ -67,6 +67,11 @@ CPDF_Object* CPDF_Reference::CloneNonCyclic(
   return new CPDF_Reference(m_pObjList, m_RefObjNum);
 }
 
+CPDF_Object* CPDF_Reference::SafeGetDirect() const {
+  CPDF_Object* obj = GetDirect();
+  return (obj && !obj->IsReference()) ? obj : nullptr;
+}
+
 void CPDF_Reference::SetRef(CPDF_IndirectObjectHolder* pDoc, uint32_t objnum) {
   m_pObjList = pDoc;
   m_RefObjNum = objnum;