Make more concrete stream classes private to .cpp files

fpdfsdk/fsdk_define.h

 // 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
 
 #ifndef FPDFSDK_FSDK_DEFINE_H_
 #define FPDFSDK_FSDK_DEFINE_H_
 
 #include "core/fpdfapi/parser/cpdf_parser.h"
 #include "core/fxge/fx_dib.h"
 #include "public/fpdfview.h"
 
 #ifdef PDF_ENABLE_XFA
 #include "fpdfsdk/fpdfxfa/cpdfxfa_context.h"
 #endif  // PDF_ENABLE_XFA
 
 #ifdef _WIN32
 #include <math.h>
 #include <tchar.h>
 #endif
 
 class CPDF_Annot;
 class CPDF_Page;
 class CPDF_PageRenderContext;
 class IFSDK_PAUSE_Adapter;
 
-class CPDF_CustomAccess final : public IFX_SeekableReadStream {
- public:
-  explicit CPDF_CustomAccess(FPDF_FILEACCESS* pFileAccess);
-  ~CPDF_CustomAccess() override {}
-
-  // IFX_SeekableReadStream
-  FX_FILESIZE GetSize() override;
-  void Release() override;
-  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override;
-
- private:
-  FPDF_FILEACCESS m_FileAccess;
-};
+// Layering prevents fxcrt from knowing about FPDF_FILEACCESS, so this can't
+// be a static method of IFX_SeekableReadStream.
+IFX_SeekableReadStream* MakeSeekableReadStream(FPDF_FILEACCESS* pFileAccess);
 
 #ifdef PDF_ENABLE_XFA
 class CFPDF_FileStream : public IFX_SeekableStream {
  public:
   explicit CFPDF_FileStream(FPDF_FILEHANDLER* pFS);
   ~CFPDF_FileStream() override {}
 
   // IFX_SeekableStream:
   IFX_SeekableStream* Retain() override;
   void Release() override;
@@ skipping 49 matching lines @@
                             int rotate,
                             int flags,
                             bool bNeedToRestore,
                             IFSDK_PAUSE_Adapter* pause);
 
 void CheckUnSupportError(CPDF_Document* pDoc, uint32_t err_code);
 void CheckUnSupportAnnot(CPDF_Document* pDoc, const CPDF_Annot* pPDFAnnot);
 void ProcessParseError(CPDF_Parser::Error err);
 
 #endif  // FPDFSDK_FSDK_DEFINE_H_