Fix a FPE in CStretchEngine::StartStretchHorz().

core/fxge/dib/dib_int.h

 // 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
 
 #ifndef CORE_FXGE_DIB_DIB_INT_H_
 #define CORE_FXGE_DIB_DIB_INT_H_
 
 #include <stdint.h>
@@ skipping 42 matching lines @@
             int src_len,
             int src_min,
             int src_max,
             int flags);
   PixelWeight* GetPixelWeight(int pixel) {
     return (PixelWeight*)(m_pWeightTables + (pixel - m_DestMin) * m_ItemSize);
   }
   int m_DestMin, m_ItemSize;
   uint8_t* m_pWeightTables;
 };
+
 class CStretchEngine {
  public:
   CStretchEngine(IFX_ScanlineComposer* pDestBitmap,
                  FXDIB_Format dest_format,
                  int dest_width,
                  int dest_height,
                  const FX_RECT& clip_rect,
                  const CFX_DIBSource* pSrcBitmap,
                  int flags);
   ~CStretchEngine();
+
   FX_BOOL Continue(IFX_Pause* pPause);
 
- public:
+  FX_BOOL StartStretchHorz();
+  FX_BOOL ContinueStretchHorz(IFX_Pause* pPause);
+  void StretchVert();
+
   FXDIB_Format m_DestFormat;
-  int m_DestBpp, m_SrcBpp, m_bHasAlpha;
+  int m_DestBpp;
+  int m_SrcBpp;
+  int m_bHasAlpha;
   IFX_ScanlineComposer* m_pDestBitmap;
   int m_DestWidth, m_DestHeight;
   FX_RECT m_DestClip;
   uint8_t* m_pDestScanline;
   uint8_t* m_pDestMaskScanline;
   FX_RECT m_SrcClip;
   const CFX_DIBSource* m_pSource;
   uint32_t* m_pSrcPalette;
-  int m_SrcWidth, m_SrcHeight;
-  int m_SrcPitch, m_InterPitch;
+  int m_SrcWidth;
+  int m_SrcHeight;
+  int m_SrcPitch;
+  int m_InterPitch;
   int m_ExtraMaskPitch;
   uint8_t* m_pInterBuf;
   uint8_t* m_pExtraAlphaBuf;
   int m_TransMethod;
   int m_Flags;
   CWeightTable m_WeightTable;
   int m_CurRow;
-  FX_BOOL StartStretchHorz();
-  FX_BOOL ContinueStretchHorz(IFX_Pause* pPause);
-  void StretchVert();
   int m_State;
 };
 
 FX_RECT FXDIB_SwapClipBox(FX_RECT& clip,
                           int width,
                           int height,
                           FX_BOOL bFlipX,
                           FX_BOOL bFlipY);
 
 #endif  // CORE_FXGE_DIB_DIB_INT_H_