Extern in .cpp file is a code smell, part 2.

core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp

 // 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
 
 #include "../../../include/fpdfapi/fpdf_parser.h"
 #include "../../../include/fxcrt/fx_string.h"
 
 // static
@@ skipping 965 matching lines @@
       }
       pBuf += actualSize;
       size -= actualSize;
       offset += actualSize;
     }
     return TRUE;
   }
   return FXSYS_memcmp(m_pDataBuf, pOther->m_pDataBuf, m_dwSize) == 0;
 }
 
-extern 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);
 CPDF_StreamAcc::CPDF_StreamAcc() {
   m_bNewBuf = FALSE;
   m_pData = NULL;
   m_dwSize = 0;
   m_pImageParam = NULL;
   m_pStream = NULL;
   m_pSrcData = NULL;
 }
 void CPDF_StreamAcc::LoadAllData(const CPDF_Stream* pStream,
                                  FX_BOOL bRawAccess,
@@ skipping 201 matching lines @@
   }
   pObj->m_ObjNum = objnum;
   m_IndirectObjs.SetAt((void*)(uintptr_t)objnum, pObj);
   if (m_LastObjNum < objnum) {
     m_LastObjNum = objnum;
   }
 }
 FX_DWORD CPDF_IndirectObjects::GetLastObjNum() const {
   return m_LastObjNum;
 }