Remove stray const qualifier from CPDF_Parser.

This prevents a subsequent std::move() at line 762 from actually doing
a move, since it can't update the const local.

Bug: 364788123
Change-Id: Ie3671a9ba9c566d57071b7065b286b5b2ec517b1
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/124070
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@google.com>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fpdfapi/parser/cpdf_parser.cpp b/core/fpdfapi/parser/cpdf_parser.cpp
index c7f0044..a2e2213 100644
--- a/core/fpdfapi/parser/cpdf_parser.cpp
+++ b/core/fpdfapi/parser/cpdf_parser.cpp
@@ -744,9 +744,8 @@
       const uint32_t gen_num = numbers[1].first;
 
       m_pSyntax->SetPos(obj_pos);
-      const RetainPtr<CPDF_Stream> pStream =
-          ToStream(m_pSyntax->GetIndirectObject(
-              nullptr, CPDF_SyntaxParser::ParseType::kStrict));
+      RetainPtr<CPDF_Stream> pStream = ToStream(m_pSyntax->GetIndirectObject(
+          nullptr, CPDF_SyntaxParser::ParseType::kStrict));
 
       if (pStream && pStream->GetDict()->GetNameFor("Type") == "XRef") {
         cross_ref_table = CPDF_CrossRefTable::MergeUp(