Revert of Make the CPDFXFA_App non-global

fpdfsdk/fpdfsave.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 "public/fpdf_save.h"
 
 #include <vector>
 
@@ skipping 67 matching lines @@
 #ifdef PDF_ENABLE_XFA
 bool SaveXFADocumentData(CPDFXFA_Document* pDocument,
                          std::vector<ScopedFileStream>* fileList) {
   if (!pDocument)
     return false;
 
   if (pDocument->GetDocType() != DOCTYPE_DYNAMIC_XFA &&
       pDocument->GetDocType() != DOCTYPE_STATIC_XFA)
     return true;
 
+  if (!CPDFXFA_App::GetInstance()->GetXFAApp())
+    return true;
+
   CXFA_FFDocView* pXFADocView = pDocument->GetXFADocView();
   if (!pXFADocView)
     return true;
 
   CPDF_Document* pPDFDocument = pDocument->GetPDFDoc();
   if (!pDocument)
     return false;
 
   CPDF_Dictionary* pRoot = pPDFDocument->GetRoot();
   if (!pRoot)
@@ skipping 213 matching lines @@
                                             FPDF_DWORD flags) {
   return FPDF_Doc_Save(document, pFileWrite, flags, FALSE, 0);
 }
 
 DLLEXPORT FPDF_BOOL STDCALL FPDF_SaveWithVersion(FPDF_DOCUMENT document,
                                                  FPDF_FILEWRITE* pFileWrite,
                                                  FPDF_DWORD flags,
                                                  int fileVersion) {
   return FPDF_Doc_Save(document, pFileWrite, flags, TRUE, fileVersion);
 }