Introduce CPDF_Document::FromFPDFDocument().

fpdfsdk/src/fpdfeditimg.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_edit.h"
 #include "../include/fsdk_define.h"
 
 DLLEXPORT FPDF_PAGEOBJECT STDCALL
 FPDFPageObj_NewImgeObj(FPDF_DOCUMENT document) {
-  if (!document)
-    return NULL;
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
   CPDF_ImageObject* pImageObj = new CPDF_ImageObject;
-  CPDF_Image* pImg = new CPDF_Image((CPDF_Document*)document);
+  CPDF_Image* pImg = new CPDF_Image(pDoc);
   pImageObj->m_pImage = pImg;
   return pImageObj;
 }
 
 DLLEXPORT FPDF_BOOL STDCALL
 FPDFImageObj_LoadJpegFile(FPDF_PAGE* pages,
                           int nCount,
                           FPDF_PAGEOBJECT image_object,
                           FPDF_FILEACCESS* fileAccess) {
   if (!image_object || !fileAccess || !pages)
@@ skipping 42 matching lines @@
   CPDF_ImageObject* pImgObj = (CPDF_ImageObject*)image_object;
   pImgObj->m_GeneralState.GetModify();
   for (int index = 0; index < nCount; index++) {
     CPDF_Page* pPage = (CPDF_Page*)pages[index];
     pImgObj->m_pImage->ResetCache(pPage, NULL);
   }
   pImgObj->m_pImage->SetImage(pBmp, FALSE);
   pImgObj->CalcBoundingBox();
   return TRUE;
 }