Fix four annoying warnings:

core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.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/fpdfapi/fpdf_parser.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../../../include/fxcodec/fx_codec.h"
 #include <limits.h>
@@ skipping 214 matching lines @@
     check *= BitsPerComponent;
     if (check > INT_MAX - 7) {
         return FALSE;
     }
     return TRUE;
 }
 ICodec_ScanlineDecoder* FPDFAPI_CreateFlateDecoder(FX_LPCBYTE src_buf, FX_DWORD src_size, int width, int height,
         int nComps, int bpc, const CPDF_Dictionary* pParams)
 {
     int predictor = 0;
-    FX_BOOL bEarlyChange = TRUE;
     int Colors = 0, BitsPerComponent = 0, Columns = 0;
     if (pParams) {
         predictor = ((CPDF_Dictionary*)pParams)->GetInteger(FX_BSTRC("Predictor"));
-        bEarlyChange = ((CPDF_Dictionary*)pParams)->GetInteger(FX_BSTRC("EarlyChange"), 1);
         Colors = pParams->GetInteger(FX_BSTRC("Colors"), 1);
         BitsPerComponent = pParams->GetInteger(FX_BSTRC("BitsPerComponent"), 8);
         Columns = pParams->GetInteger(FX_BSTRC("Columns"), 1);
         if (!CheckFlateDecodeParams(Colors, BitsPerComponent, Columns)) {
             return NULL;
         }
     }
     return CPDF_ModuleMgr::Get()->GetFlateModule()->CreateDecoder(src_buf, src_size, width, height,
             nComps, bpc, predictor, Colors, BitsPerComponent, Columns);
 }
@@ skipping 271 matching lines @@
     }
 }
 FX_DWORD FlateDecode(const FX_BYTE* src_buf, FX_DWORD src_size, FX_LPBYTE& dest_buf, FX_DWORD& dest_size)
 {
     CCodec_ModuleMgr* pEncoders = CPDF_ModuleMgr::Get()->GetCodecModule();
     if (pEncoders) {
         return pEncoders->GetFlateModule()->FlateOrLZWDecode(FALSE, src_buf, src_size, FALSE, 0, 0, 0, 0, 0, dest_buf, dest_size);
     }
     return 0;
 }