Add type cast definitions for CPDF_String.

core/src/fpdfapi/fpdf_edit/fpdf_edit_create.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/fxcrt/fx_ext.h"
 #include "../../../include/fpdfapi/fpdf_serial.h"
 #include "../../../include/fpdfapi/fpdf_parser.h"
 #include "editint.h"
@@ skipping 24 matching lines @@
       if (pFile->AppendString(FX_BSTRC(" ")) < 0) {
         return -1;
       }
       if ((len = pFile->AppendString(pObj->GetString())) < 0) {
         return -1;
       }
       offset += len + 1;
       break;
     case PDFOBJ_STRING: {
       CFX_ByteString str = pObj->GetString();
-      FX_BOOL bHex = ((CPDF_String*)pObj)->IsHex();
+      FX_BOOL bHex = pObj->AsString()->IsHex();
       if ((len = pFile->AppendString(PDF_EncodeString(str, bHex))) < 0) {
         return -1;
       }
       offset += len;
       break;
     }
     case PDFOBJ_NAME: {
       if (pFile->AppendString(FX_BSTRC("/")) < 0) {
         return -1;
       }
@@ skipping 1053 matching lines @@
       if (m_File.AppendString(FX_BSTRC(" ")) < 0) {
         return -1;
       }
       if ((len = m_File.AppendString(pObj->GetString())) < 0) {
         return -1;
       }
       m_Offset += len + 1;
       break;
     case PDFOBJ_STRING: {
       CFX_ByteString str = pObj->GetString();
-      FX_BOOL bHex = ((CPDF_String*)pObj)->IsHex();
+      FX_BOOL bHex = pObj->AsString()->IsHex();
       if (m_pCryptoHandler == NULL || !bEncrypt) {
         CFX_ByteString content = PDF_EncodeString(str, bHex);
         if ((len = m_File.AppendString(content)) < 0) {
           return -1;
         }
         m_Offset += len;
         break;
       }
       CPDF_Encryptor encryptor;
       encryptor.Initialize(m_pCryptoHandler, objnum, (uint8_t*)str.c_str(),
@@ skipping 998 matching lines @@
   m_bNewCrypto = FALSE;
   if (!m_bStandardSecurity) {
     return;
   }
   if (m_pEncryptDict) {
     m_pEncryptDict->Release();
     m_pEncryptDict = NULL;
   }
   m_bStandardSecurity = FALSE;
 }