FPDF_Creator can only create file through embedder-supplied callback.

core/include/fpdfapi/fpdf_serial.h

Index: core/include/fpdfapi/fpdf_serial.h
diff --git a/core/include/fpdfapi/fpdf_serial.h b/core/include/fpdfapi/fpdf_serial.h
index 7197e0d7b063dd60291265d20941837e19a1aee3..4a325341cb73ccd7b7c04ec9f1cd84c1a2992f42 100644
--- a/core/include/fpdfapi/fpdf_serial.h
+++ b/core/include/fpdfapi/fpdf_serial.h
@@ -17,22 +17,15 @@ CFX_ByteTextBuf& operator<<(CFX_ByteTextBuf& buf, const CPDF_Object* pObj);
 #define FPDFCREATE_NO_ORIGINAL 2
 #define FPDFCREATE_PROGRESSIVE 4
 #define FPDFCREATE_OBJECTSTREAM 8
+
 class CPDF_Creator {
  public:
   CPDF_Creator(CPDF_Document* pDoc);
-
   ~CPDF_Creator();
 
   void RemoveSecurity();
-
-  FX_BOOL Create(const FX_WCHAR* filename, FX_DWORD flags = 0);
-
-  FX_BOOL Create(const FX_CHAR* filename, FX_DWORD flags = 0);
-
   FX_BOOL Create(IFX_StreamWrite* pFile, FX_DWORD flags = 0);
-
   int32_t Continue(IFX_Pause* pPause = NULL);
-
   FX_BOOL SetFileVersion(int32_t fileVersion = 17);
 
  protected: