Prevent base::CheckedNumeric from leaking outside of pdfium.

fpdfsdk/src/fpdfview.cpp

 // Copyright 2014 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 "../include/fsdk_define.h"
 #include "../include/fsdk_mgr.h"
 #include "../include/fpdfview.h"
 #include "../include/fsdk_rendercontext.h"
 #include "../include/fpdf_progressive.h"
 #include "../include/fpdf_ext.h"
+#include "../../../core/src/fxcrt/fx_safe_types.h"
 #include "../../third_party/numerics/safe_conversions_impl.h"
 
 CPDF_CustomAccess::CPDF_CustomAccess(FPDF_FILEACCESS* pFileAccess)
 {
         if (pFileAccess)
                 m_FileAccess = *pFileAccess;
 }
 
 FX_BOOL CPDF_CustomAccess::ReadBlock(void* buffer, FX_FILESIZE offset, size_t size)
 {
@@ skipping 836 matching lines @@
     if (!buffer) {
         buflen = len;
     } else if (buflen >= len) {
         memcpy(buffer, utf16Name.c_str(), len);
         buflen = len;
     } else {
         buflen = -1;
     }
     return (FPDF_DEST)pDestObj;
 }