Fix two issues shown by bug 489995

core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp

Index: core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
index 9e1434139c99cfe4a59f8e2d9a89798ee3d4e4f4..63454d2cb5013d0681fb49a1bc157f24114276b9 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
@@ -410,7 +410,7 @@ CFX_ByteTextBuf& operator<<(CFX_ByteTextBuf& buf, const CPDF_Object* pObj) {
         CFX_ByteString key;
         CPDF_Object* pValue = p->GetNextElement(pos, key);
         buf << FX_BSTRC("/") << PDF_NameEncode(key);
-        if (pValue->GetObjNum()) {
+        if (pValue && pValue->GetObjNum()) {
           buf << " " << pValue->GetObjNum() << FX_BSTRC(" 0 R ");
         } else {
           buf << pValue;