Remove custom memory manager

core/src/fxge/win32/fx_win32_gdipext.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/fxge/fx_ge.h"
 #if _FX_OS_ == _FX_WIN32_DESKTOP_ || _FX_OS_ == _FX_WIN64_
 #include <windows.h>
 #include <gdiplus.h>
@@ skipping 1182 matching lines @@
         dest_pixel_format = PixelFormat32bppARGB;
     }
     LPBYTE buf = FX_Alloc(BYTE, info_size);
     if (!buf) {
         if (pStream) {
             pStream->Release();
         }
         return NULL;
     }
     BITMAPINFOHEADER* pbmih = (BITMAPINFOHEADER*)buf;
-    FXSYS_memset32(buf, 0, info_size);
     pbmih->biBitCount = bpp;
     pbmih->biCompression = BI_RGB;
     pbmih->biHeight = -(int)height;
     pbmih->biPlanes = 1;
     pbmih->biWidth = width;
     Rect rect(0, 0, width, height);
     BitmapData* pBitmapData = FX_Alloc(BitmapData, 1);
     if (!pBitmapData) {
         if (pStream) {
             pStream->Release();
@@ skipping 63 matching lines @@
         FXSYS_memcpy32(pData, pInfo->pScan0, dest_pitch * height);
     } else for (int i = 0; i < height; i ++) {
             FXSYS_memcpy32(pData + dest_pitch * i, pInfo->pScan0 + pInfo->Stride * i, dest_pitch);
         }
     CFX_DIBitmap* pDIBitmap = _FX_WindowsDIB_LoadFromBuf(pInfo->pbmi, pData, pInfo->pbmi->bmiHeader.biBitCount == 32);
     FX_Free(pData);
     FreeDIBitmap(pInfo);
     return pDIBitmap;
 }
 #endif