Merge to XFA: Introduce CPDFDocumentFromFPDFDocument().

fpdfsdk/src/fpdfeditimg.cpp

Index: fpdfsdk/src/fpdfeditimg.cpp
diff --git a/fpdfsdk/src/fpdfeditimg.cpp b/fpdfsdk/src/fpdfeditimg.cpp
index 269b382d8932c129f5c023348459a2585e810021..09295aa3c45293646cb55116a32559b197069cfd 100644
--- a/fpdfsdk/src/fpdfeditimg.cpp
+++ b/fpdfsdk/src/fpdfeditimg.cpp
@@ -11,10 +11,11 @@
 
 DLLEXPORT FPDF_PAGEOBJECT STDCALL
 FPDFPageObj_NewImgeObj(FPDF_DOCUMENT document) {
-  if (!document)
-    return NULL;
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
   CPDF_ImageObject* pImageObj = new CPDF_ImageObject;
-  CPDF_Image* pImg = new CPDF_Image(((CPDFXFA_Document*)document)->GetPDFDoc());
+  CPDF_Image* pImg = new CPDF_Image(pDoc);
   pImageObj->m_pImage = pImg;
   return pImageObj;
 }