Fix all the code which has duplicate variable declarations

core/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 "core/fpdfapi/fpdf_edit/editint.h"
 
 #include <vector>
 
@@ skipping 761 matching lines @@
     return FALSE;
   }
   offset += len + 7;
   if (m_PrevOffset > 0) {
     if (pFile->AppendString("/Prev ") < 0) {
       return FALSE;
     }
     FX_CHAR offset_buf[20];
     FXSYS_memset(offset_buf, 0, sizeof(offset_buf));
     FXSYS_i64toa(m_PrevOffset, offset_buf, 10);
-    int32_t len = (int32_t)FXSYS_strlen(offset_buf);
-    if (pFile->AppendBlock(offset_buf, len) < 0) {
+    int32_t offset_len = (int32_t)FXSYS_strlen(offset_buf);
+    if (pFile->AppendBlock(offset_buf, offset_len) < 0) {
       return FALSE;
     }
-    offset += len + 6;
+    offset += offset_len + 6;
   }
   FX_BOOL bPredictor = TRUE;
   CPDF_FlateEncoder encoder(m_Buffer.GetBuffer(), m_Buffer.GetLength(), TRUE,
                             bPredictor);
   if (pFile->AppendString("/Filter /FlateDecode") < 0) {
     return FALSE;
   }
   offset += 20;
   if (bPredictor) {
     if ((len = pFile->AppendString("/DecodeParms<</Columns 7/Predictor 12>>")) <
@@ skipping 1212 matching lines @@
   m_pCryptoHandler = nullptr;
 }
 void CPDF_Creator::ResetStandardSecurity() {
   if (!m_bLocalCryptoHandler)
     return;
 
   delete m_pCryptoHandler;
   m_pCryptoHandler = nullptr;
   m_bLocalCryptoHandler = FALSE;
 }