Revert "Remove FX_Alloc() null checks now that it can't return NULL."

core/src/fxge/win32/fx_win32_device.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 "../../../include/fxge/fx_ge_win32.h"
 #include <crtdbg.h>
@@ skipping 637 matching lines @@
     int a;
     FX_COLORREF rgb;
     ArgbDecode(argb, a, rgb);
     LOGBRUSH lb;
     lb.lbColor = rgb;
     lb.lbStyle = BS_SOLID;
     lb.lbHatch = 0;
     FX_DWORD* pDash = NULL;
     if (pGraphState->m_DashCount) {
         pDash = FX_Alloc(FX_DWORD, pGraphState->m_DashCount);
+        if (!pDash) {
+            return NULL;
+        }
         for (int i = 0; i < pGraphState->m_DashCount; i ++) {
             pDash[i] = FXSYS_round(pMatrix ? pMatrix->TransformDistance(pGraphState->m_DashArray[i]) : pGraphState->m_DashArray[i]);
             if (pDash[i] < 1) {
                 pDash[i] = 1;
             }
         }
     }
     HPEN hPen = ExtCreatePen(PenStyle, (DWORD)FXSYS_ceil(width), &lb, pGraphState->m_DashCount, (const DWORD*)pDash);
     if (pDash) {
         FX_Free(pDash);
@@ skipping 526 matching lines @@
     if (m_hDC) {
         SelectObject(m_hDC, m_hOldBitmap);
         DeleteDC(m_hDC);
     }
     if (m_hBitmap) {
         DeleteObject(m_hBitmap);
     }
     delete GetBitmap();
 }
 #endif