Cast more consistently in CPDF_Stream.

This is a follow-up to https://pdfium-review.googlesource.com/91150,
which widened `m_dwSize` to a size_t.

Change-Id: I6e750055ef0fad1c47161d94b369e2330760ca78
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/96210
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/core/fpdfapi/parser/cpdf_stream.cpp b/core/fpdfapi/parser/cpdf_stream.cpp
index f240f25..3257ba4 100644
--- a/core/fpdfapi/parser/cpdf_stream.cpp
+++ b/core/fpdfapi/parser/cpdf_stream.cpp
@@ -93,8 +93,9 @@
   m_pDataBuf.reset();
   m_pFile = std::move(pFile);
   m_pDict = std::move(pDict);
-  m_dwSize = pdfium::base::checked_cast<uint32_t>(m_pFile->GetSize());
-  m_pDict->SetNewFor<CPDF_Number>("Length", static_cast<int>(m_dwSize));
+  m_dwSize = pdfium::base::checked_cast<size_t>(m_pFile->GetSize());
+  m_pDict->SetNewFor<CPDF_Number>("Length",
+                                  pdfium::base::checked_cast<int>(m_dwSize));
 }
 
 RetainPtr<CPDF_Object> CPDF_Stream::Clone() const {