Fix layering violation in CPDF_Document::FromFPDFDocument().

fpdfsdk/src/fpdfsave.cpp

Index: fpdfsdk/src/fpdfsave.cpp
diff --git a/fpdfsdk/src/fpdfsave.cpp b/fpdfsdk/src/fpdfsave.cpp
index e0f239828dc38c7d4e5b26c13403b951c4929498..7115f6d651a17ca44c26b3dfab8c946431020b5b 100644
--- a/fpdfsdk/src/fpdfsave.cpp
+++ b/fpdfsdk/src/fpdfsave.cpp
@@ -56,7 +56,7 @@ FPDF_BOOL _FPDF_Doc_Save(FPDF_DOCUMENT document,
                          FPDF_DWORD flags,
                          FPDF_BOOL bSetVersion,
                          int fileVerion) {
-  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
   if (!pDoc)
     return 0;