Force compiler to deduce src type for checked_cast<dst, src>.

fpdfsdk/fpdfview.cpp

Index: fpdfsdk/fpdfview.cpp
diff --git a/fpdfsdk/fpdfview.cpp b/fpdfsdk/fpdfview.cpp
index 9142dc78c9352f91cfc8f41c8ae6ddb84f43d247..334c14cd45f9d1ed834d80b72bc3595c0de775cd 100644
--- a/fpdfsdk/fpdfview.cpp
+++ b/fpdfsdk/fpdfview.cpp
@@ -192,8 +192,7 @@ bool CPDF_CustomAccess::ReadBlock(void* buffer,
   if (offset < 0)
     return false;
 
-  FX_SAFE_FILESIZE newPos =
-      pdfium::base::checked_cast<FX_FILESIZE, size_t>(size);
+  FX_SAFE_FILESIZE newPos = pdfium::base::checked_cast<FX_FILESIZE>(size);
   newPos += offset;
   if (!newPos.IsValid() ||
       newPos.ValueOrDie() > static_cast<FX_FILESIZE>(m_FileAccess.m_FileLen)) {
@@ -388,8 +387,7 @@ class CMemFile final : public IFX_SeekableReadStream {
     if (offset < 0) {
       return false;
     }
-    FX_SAFE_FILESIZE newPos =
-        pdfium::base::checked_cast<FX_FILESIZE, size_t>(size);
+    FX_SAFE_FILESIZE newPos = pdfium::base::checked_cast<FX_FILESIZE>(size);
     newPos += offset;
     if (!newPos.IsValid() || newPos.ValueOrDie() > m_size) {
       return false;