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

core/src/fpdfdoc/doc_ap.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/fpdfdoc/fpdf_ap.h"
 #include "../../include/fpdfdoc/fpdf_doc.h"
 #include "../../include/fpdfdoc/fpdf_vt.h"
+#include "doc_utils.h"
 #include "pdf_vt.h"
-#include "../../include/fpdfdoc/fpdf_ap.h"
+
 FX_BOOL FPDF_GenerateAP(CPDF_Document* pDoc, CPDF_Dictionary* pAnnotDict) {
   if (!pAnnotDict ||
       pAnnotDict->GetConstString("Subtype") != FX_BSTRC("Widget")) {
     return FALSE;
   }
   CFX_ByteString field_type = FPDF_GetFieldAttr(pAnnotDict, "FT")->GetString();
   FX_DWORD flags = FPDF_GetFieldAttr(pAnnotDict, "Ff")
                        ? FPDF_GetFieldAttr(pAnnotDict, "Ff")->GetInteger()
                        : 0;
   if (field_type == "Tx") {
@@ skipping 48 matching lines @@
                            CPDF_Dictionary* pResDict,
                            CPDF_Font* pDefFont,
                            const CFX_ByteString& sDefFontAlias)
     : m_pDocument(pDoc),
       m_pResDict(pResDict),
       m_pDefFont(pDefFont),
       m_sDefFontAlias(sDefFontAlias),
       m_pSysFont(NULL),
       m_sSysFontAlias() {}
 CPVT_FontMap::~CPVT_FontMap() {}
-extern CPDF_Font* AddNativeInterFormFont(CPDF_Dictionary*& pFormDict,
-                                         CPDF_Document* pDocument,
-                                         CFX_ByteString& csNameTag);
 void CPVT_FontMap::GetAnnotSysPDFFont(CPDF_Document* pDoc,
                                       CPDF_Dictionary* pResDict,
                                       CPDF_Font*& pSysFont,
                                       CFX_ByteString& sSysFontAlias) {
   if (pDoc && pResDict) {
     CFX_ByteString sFontAlias;
     CPDF_Dictionary* pFormDict = pDoc->GetRoot()->GetDict("AcroForm");
     if (CPDF_Font* pPDFFont =
             AddNativeInterFormFont(pFormDict, pDoc, sSysFontAlias)) {
       if (CPDF_Dictionary* pFontList = pResDict->GetDict("Font")) {
@@ skipping 839 matching lines @@
                    << "\n";
       break;
     case CT_CMYK:
       sColorStream << color.fColor1 << " " << color.fColor2 << " "
                    << color.fColor3 << " " << color.fColor4 << " "
                    << (bFillOrStroke ? "k" : "K") << "\n";
       break;
   }
   return sColorStream.GetByteString();
 }