Extern in .cpp file is a code smell, part 2.

core/src/fxge/dib/fx_dib_main.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_dib.h"
 #include "../../../include/fxge/fx_ge.h"
 #include "../../../include/fxcodec/fx_codec.h"
 #include "dib_int.h"
@@ skipping 1533 matching lines @@
 }
 CFX_ImageRenderer::CFX_ImageRenderer() {
   m_Status = 0;
   m_pTransformer = NULL;
   m_bRgbByteOrder = FALSE;
   m_BlendType = FXDIB_BLEND_NORMAL;
 }
 CFX_ImageRenderer::~CFX_ImageRenderer() {
   delete m_pTransformer;
 }
-extern FX_RECT _FXDIB_SwapClipBox(FX_RECT& clip,
-                                  int width,
-                                  int height,
-                                  FX_BOOL bFlipX,
-                                  FX_BOOL bFlipY);
 FX_BOOL CFX_ImageRenderer::Start(CFX_DIBitmap* pDevice,
                                  const CFX_ClipRgn* pClipRgn,
                                  const CFX_DIBSource* pSource,
                                  int bitmap_alpha,
                                  FX_DWORD mask_color,
                                  const CFX_AffineMatrix* pMatrix,
                                  FX_DWORD dib_flags,
                                  FX_BOOL bRgbByteOrder,
                                  int alpha_flag,
                                  void* pIccTransform,
@@ skipping 149 matching lines @@
   if (!m_pBitmap->Create(width, height, src_format)) {
     delete m_pBitmap;
     m_pBitmap = NULL;
     return FALSE;
   }
   if (pSrcPalette) {
     m_pBitmap->CopyPalette(pSrcPalette);
   }
   return TRUE;
 }