Start proxying CPDFSDK_Document methods through CPDFSDK_FormFillEnvironment

fpdfsdk/fpdfxfa/cpdfxfa_document.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 "fpdfsdk/fpdfxfa/cpdfxfa_document.h"
 
 #include "core/fpdfapi/parser/cpdf_document.h"
 #include "fpdfsdk/cpdfsdk_document.h"
@@ skipping 183 matching lines @@
 }
 
 void CPDFXFA_Document::RemovePage(CPDFXFA_Page* page) {
   m_XFAPageList.SetAt(page->GetPageIndex(), nullptr);
 }
 
 void CPDFXFA_Document::ClearChangeMark() {
   if (m_pSDKDoc)
     m_pSDKDoc->ClearChangeMark();
 }
+
+CPDFSDK_FormFillEnvironment* CPDFXFA_Document::GetFormFillEnv() const {
+  return m_pSDKDoc ? m_pSDKDoc->GetEnv() : nullptr;
+}