Update allocPageErrorCode only when mmap fails.

third_party/WebKit/Source/wtf/PageAllocator.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 61 matching lines @@
 // the hint. If false, the hint is mandatory and a successful allocation will
 // not differ from the hint.
 static void* systemAllocPages(void* hint, size_t len, PageAccessibilityConfiguration pageAccessibility)
 {
     ASSERT(!(len & kPageAllocationGranularityOffsetMask));
     ASSERT(!(reinterpret_cast<uintptr_t>(hint) & kPageAllocationGranularityOffsetMask));
     void* ret;
 #if OS(WIN)
     DWORD accessFlag = pageAccessibility == PageAccessible ? PAGE_READWRITE : PAGE_NOACCESS;
     ret = VirtualAlloc(hint, len, MEM_RESERVE | MEM_COMMIT, accessFlag);
-    allocPageErrorCode = !ret ? GetLastError() : ERROR_SUCCESS;
+    if (!ret)
+        allocPageErrorCode = GetLastError();
 #else
     int accessFlag = pageAccessibility == PageAccessible ? (PROT_READ | PROT_WRITE) : PROT_NONE;
     ret = mmap(hint, len, accessFlag, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
     if (ret == MAP_FAILED) {
         allocPageErrorCode = errno;
         ret = 0;
-    } else {
-        allocPageErrorCode = 0;
     }
 #endif
     return ret;
 }
 
 // Trims base to given length and alignment. Windows returns null on failure and frees base.
 static void* trimMapping(void *base, size_t baseLen, size_t trimLen, uintptr_t align, PageAccessibilityConfiguration pageAccessibility)
 {
     size_t preSlack = reinterpret_cast<uintptr_t>(base) & (align - 1);
     if (preSlack)
@@ skipping 168 matching lines @@
 #endif
 }
 
 uint32_t getAllocPageErrorCode()
 {
     return allocPageErrorCode;
 }
 
 } // namespace WTF