Move extern fpdf_font_charset.cpp function prototypes to header

core/src/fpdftext/fpdf_text.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 "../../../third_party/base/nonstd_unique_ptr.h"
 #include "../../include/fpdfapi/fpdf_page.h"
 #include "../../include/fpdfapi/fpdf_pageobj.h"
+#include "../../include/fpdfapi/fpdf_resource.h"
 #include "../../include/fpdftext/fpdf_text.h"
 #include "../../include/fxcrt/fx_arb.h"
 #include "../../include/fxcrt/fx_ucd.h"
 #include "text_int.h"
 #include "txtproc.h"
 
-extern const FX_CHAR* FCS_GetAltStr(FX_WCHAR);
 CFX_ByteString CharFromUnicodeAlt(FX_WCHAR unicode, int destcp, const FX_CHAR* defchar)
 {
     if (destcp == 0) {
         if (unicode < 0x80) {
             return CFX_ByteString((char)unicode);
         }
         const FX_CHAR* altstr = FCS_GetAltStr(unicode);
         if (altstr) {
             return CFX_ByteString(altstr, -1);
         }
@@ skipping 742 matching lines @@
 {
     buffer.EstimateSize(0, 10240);
     CPDF_Page page;
     page.Load(pDoc, pPage);
     CPDF_ParseOptions options;
     options.m_bTextOnly = TRUE;
     options.m_bSeparateForm = FALSE;
     page.ParseContent(&options);
     _PDF_GetTextStream_Unicode(buffer, &page, TRUE, NULL);
 }