Add a test for the HexDecode method.

core/include/fpdfapi/fpdf_parser.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 CORE_INCLUDE_FPDFAPI_FPDF_PARSER_H_
 #define CORE_INCLUDE_FPDFAPI_FPDF_PARSER_H_
 
 #include "../../../public/fpdf_dataavail.h"
@@ skipping 926 matching lines @@
   PDF_DATAAVAIL_PAGETREE,
   PDF_DATAAVAIL_PAGE,
   PDF_DATAAVAIL_PAGE_LATERLOAD,
   PDF_DATAAVAIL_RESOURCES,
   PDF_DATAAVAIL_DONE,
   PDF_DATAAVAIL_ERROR,
   PDF_DATAAVAIL_LOADALLFILE,
   PDF_DATAAVAIL_TRAILER_APPEND
 };
 
+// Public for testing.
+FX_DWORD A85Decode(const uint8_t* src_buf,
+                   FX_DWORD src_size,
+                   uint8_t*& dest_buf,
+                   FX_DWORD& dest_size);
+// Public for testing.
+FX_DWORD HexDecode(const uint8_t* src_buf,
+                   FX_DWORD src_size,
+                   uint8_t*& dest_buf,
+                   FX_DWORD& dest_size);
+// Public for testing.
+FX_DWORD FPDFAPI_FlateOrLZWDecode(FX_BOOL bLZW,
+                                  const uint8_t* src_buf,
+                                  FX_DWORD src_size,
+                                  CPDF_Dictionary* pParams,
+                                  FX_DWORD estimated_size,
+                                  uint8_t*& dest_buf,
+                                  FX_DWORD& dest_size);
 FX_BOOL PDF_DataDecode(const uint8_t* src_buf,
                        FX_DWORD src_size,
                        const CPDF_Dictionary* pDict,
                        uint8_t*& dest_buf,
                        FX_DWORD& dest_size,
                        CFX_ByteString& ImageEncoding,
                        CPDF_Dictionary*& pImageParms,
                        FX_DWORD estimated_size,
                        FX_BOOL bImageAcc);
 
 #endif  // CORE_INCLUDE_FPDFAPI_FPDF_PARSER_H_