Re-enable all the windows warnings except 4267

core/fpdfapi/fpdf_parser/cpdf_data_avail.cpp

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/fpdf_parser/include/ipdf_data_avail.h"
 
 #include "core/fpdfapi/fpdf_parser/cpdf_data_avail.h"
 #include "core/fpdfapi/fpdf_parser/fpdf_parser_utility.h"
@@ skipping 698 matching lines @@
   }
 
   m_docStatus =
       m_bSupportHintTable ? PDF_DATAAVAIL_HINTTABLE : PDF_DATAAVAIL_DONE;
   return TRUE;
 }
 
 FX_BOOL CPDF_DataAvail::IsDataAvail(FX_FILESIZE offset,
                                     uint32_t size,
                                     IPDF_DataAvail::DownloadHints* pHints) {
-  if (offset > m_dwFileLen)
+  if (offset < 0 || offset > m_dwFileLen)
     return TRUE;
 
-  FX_SAFE_DWORD safeSize = pdfium::base::checked_cast<uint32_t>(offset);
+  FX_SAFE_FILESIZE safeSize = offset;
   safeSize += size;
   safeSize += 512;
   if (!safeSize.IsValid() || safeSize.ValueOrDie() > m_dwFileLen)
     size = m_dwFileLen - offset;
   else
     size += 512;
 
   if (!m_pFileAvail->IsDataAvail(offset, size)) {
     pHints->AddSegment(offset, size);
     return FALSE;
@@ skipping 1102 matching lines @@
   return FormAvailable;
 }
 
 CPDF_DataAvail::PageNode::PageNode() : m_type(PDF_PAGENODE_UNKNOWN) {}
 
 CPDF_DataAvail::PageNode::~PageNode() {
   for (int32_t i = 0; i < m_childNode.GetSize(); ++i)
     delete m_childNode[i];
   m_childNode.RemoveAll();
 }