Add safe FX_Alloc2D() macro

core/src/fxge/dib/fx_dib_engine.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 "dib_int.h"
 #include <limits.h>
@@ skipping 298 matching lines @@
 FX_BOOL CStretchEngine::StartStretchHorz()
 {
     if (m_DestWidth == 0 || m_pDestScanline == NULL || m_SrcClip.Height() > (int)((1U << 29) / m_InterPitch) || m_SrcClip.Height() == 0) {
         return FALSE;
     }
     m_pInterBuf = FX_TryAlloc(unsigned char, m_SrcClip.Height() * m_InterPitch);
     if (m_pInterBuf == NULL) {
         return FALSE;
     }
     if (m_pSource && m_bHasAlpha && m_pSource->m_pAlphaMask) {
-        m_pExtraAlphaBuf = FX_Alloc(unsigned char, m_SrcClip.Height() * m_ExtraMaskPitch);
-        if (!m_pExtraAlphaBuf) {
-            return FALSE;
-        }
+        m_pExtraAlphaBuf = FX_Alloc2D(unsigned char, m_SrcClip.Height(), m_ExtraMaskPitch);
         FX_DWORD size = (m_DestClip.Width() * 8 + 31) / 32 * 4;
         m_pDestMaskScanline = FX_TryAlloc(unsigned char, size);
         if (!m_pDestMaskScanline) {
             return FALSE;
         }
     }
     m_WeightTable.Calc(m_DestWidth, m_DestClip.left, m_DestClip.right, m_SrcWidth, m_SrcClip.left, m_SrcClip.right, m_Flags);
     if (m_WeightTable.m_pWeightTables == NULL) {
         return FALSE;
     }
@@ skipping 507 matching lines @@
             return TRUE;
         }
         m_pSource->DownSampleScanline(src_y, m_pScanline, m_DestBPP, m_DestWidth, m_bFlipX, m_ClipRect.left, result_width);
         if (m_pMaskScanline) {
             m_pSource->m_pAlphaMask->DownSampleScanline(src_y, m_pMaskScanline, 1, m_DestWidth, m_bFlipX, m_ClipRect.left, result_width);
         }
         m_pDest->ComposeScanline(dest_y, m_pScanline, m_pMaskScanline);
     }
     return FALSE;
 }