Remove IPDF_TextPage, IPDF_TextPageFind and IPDF_LinkExtract interfaces.

fpdfsdk/fpdf_searchex.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 "public/fpdf_searchex.h"
 
-#include "core/fpdftext/include/ipdf_textpage.h"
+#include "core/fpdftext/include/cpdf_textpage.h"
 
 DLLEXPORT int STDCALL
 FPDFText_GetCharIndexFromTextIndex(FPDF_TEXTPAGE text_page, int nTextIndex) {
   if (!text_page)
     return -1;
-  return ((IPDF_TextPage*)text_page)->CharIndexFromTextIndex(nTextIndex);
+  return static_cast<CPDF_TextPage*>(text_page)
+      ->CharIndexFromTextIndex(nTextIndex);
 }