Don't depend on base::win in PartitionAlloc.

base/allocator/partition_allocator/address_space_randomization.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/allocator/partition_allocator/address_space_randomization.h"
 
 #include "base/allocator/partition_allocator/page_allocator.h"
 #include "base/allocator/partition_allocator/spin_lock.h"
 #include "base/win/windows_version.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #else
 #include <sys/time.h>
 #include <unistd.h>
 #endif
 
+// VersionHelpers.h must be included after windows.h.
+#if defined(OS_WIN)
+#include <VersionHelpers.h>
+#endif
+
 namespace base {
 
 namespace {
 
 // This is the same PRNG as used by tcmalloc for mapping address randomness;
 // see http://burtleburtle.net/bob/rand/smallprng.html
 struct ranctx {
   subtle::SpinLock lock;
   bool initialized;
   uint32_t a;
@@ skipping 56 matching lines @@
   uintptr_t random;
   random = static_cast<uintptr_t>(ranval(&s_ranctx));
 #if defined(ARCH_CPU_X86_64)
   random <<= 32UL;
   random |= static_cast<uintptr_t>(ranval(&s_ranctx));
 // This address mask gives a low likelihood of address space collisions. We
 // handle the situation gracefully if there is a collision.
 #if defined(OS_WIN)
   random &= 0x3ffffffffffUL;
   // Windows >= 8.1 has the full 47 bits. Use them where available.
-  if (base::win::GetVersion() < base::win::Version::VERSION_WIN8_1) {
+  static bool windows_81 = false;
+  static bool windows_81_initialized = false;
+  if (!windows_81_initialized) {
+    windows_81 = IsWindows8Point1OrGreater();
+    windows_81_initialized = true;
+  }
+  if (!windows_81) {
     random += 0x10000000000UL;
   }
 #elif defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
   // This range is copied from the TSan source, but works for all tools.
   random &= 0x007fffffffffUL;
   random += 0x7e8000000000UL;
 #else
   // Linux and OS X support the full 47-bit user space of x64 processors.
   random &= 0x3fffffffffffUL;
 #endif
@@ skipping 16 matching lines @@
   // This is a good range on Windows, Linux and Mac.
   // Allocates in the 0.5-1.5GB region.
   random &= 0x3fffffff;
   random += 0x20000000;
 #endif  // defined(ARCH_CPU_X86_64)
   random &= kPageAllocationGranularityBaseMask;
   return reinterpret_cast<void*>(random);
 }
 
 }  // namespace base