Remove unused code.

core/fxcodec/codec/fx_codec_flate.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/fxcodec/codec/codec_int.h"
 
 #include <algorithm>
 #include <memory>
 
 #include "core/fxcodec/include/fx_codec.h"
-#include "core/fxcodec/include/fx_codec_flate.h"
 #include "core/fxcrt/include/fx_ext.h"
 #include "third_party/zlib_v128/zlib.h"
 
 extern "C" {
 static void* my_alloc_func(void* opaque,
                            unsigned int items,
                            unsigned int size) {
   return FX_Alloc2D(uint8_t, items, size);
 }
 static void my_free_func(void* opaque, void* address) {
@@ skipping 837 matching lines @@
                                    uint32_t src_size,
                                    uint8_t** dest_buf,
                                    uint32_t* dest_size) {
   uint8_t* pSrcBuf = FX_Alloc(uint8_t, src_size);
   FXSYS_memcpy(pSrcBuf, src_buf, src_size);
   PNG_PredictorEncode(&pSrcBuf, &src_size);
   bool ret = Encode(pSrcBuf, src_size, dest_buf, dest_size);
   FX_Free(pSrcBuf);
   return ret;
 }