Refcount all the IFX_ stream classes all the time.

xfa/fxfa/app/xfa_checksum.cpp

Index: xfa/fxfa/app/xfa_checksum.cpp
diff --git a/xfa/fxfa/app/xfa_checksum.cpp b/xfa/fxfa/app/xfa_checksum.cpp
index 01035f8ea4299a61ebbb40d1948d1f0c8d68cac2..61cbe97fb37cdb6eb18ccf43d6027eee6dc2fb18 100644
--- a/xfa/fxfa/app/xfa_checksum.cpp
+++ b/xfa/fxfa/app/xfa_checksum.cpp
@@ -225,11 +225,13 @@ void CXFA_ChecksumContext::StartChecksum() {
   m_pSAXReader = new CFX_SAXReader;
 }
 
-bool CXFA_ChecksumContext::UpdateChecksum(IFX_SeekableReadStream* pSrcFile,
-                                          FX_FILESIZE offset,
-                                          size_t size) {
+bool CXFA_ChecksumContext::UpdateChecksum(
+    const CFX_RetainPtr<IFX_SeekableReadStream>& pSrcFile,
+    FX_FILESIZE offset,
+    size_t size) {
   if (!m_pSAXReader || !pSrcFile)
     return false;
+
   if (size < 1)
     size = pSrcFile->GetSize();