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

base/allocator/partition_allocator/address_space_randomization.cc

Index: base/allocator/partition_allocator/address_space_randomization.cc
diff --git a/base/allocator/partition_allocator/address_space_randomization.cc b/base/allocator/partition_allocator/address_space_randomization.cc
index ca9efdd8be49e527e901358d2db0b1ed43cd0ae3..d54fb4434e3104c8c7b90aedfcc767887cfef5be 100644
--- a/base/allocator/partition_allocator/address_space_randomization.cc
+++ b/base/allocator/partition_allocator/address_space_randomization.cc
@@ -16,6 +16,11 @@
 #include <unistd.h>
 #endif
 
+// VersionHelpers.h must be included after windows.h.
+#if defined(OS_WIN)
+#include <VersionHelpers.h>
+#endif
+
 namespace base {
 
 namespace {
@@ -92,7 +97,13 @@ void* GetRandomPageBase() {
 #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)