Make the windows_version.h functions threadsafe by using a singleton.

chrome/installer/gcapi/gcapi.cc

Index: chrome/installer/gcapi/gcapi.cc
===================================================================
--- chrome/installer/gcapi/gcapi.cc	(revision 80528)
+++ chrome/installer/gcapi/gcapi.cc	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -8,11 +8,14 @@
 #include <atlcom.h>
 #include <windows.h>
 #include <sddl.h>
-#include <stdlib.h>
+#define STRSAFE_NO_DEPRECATE
 #include <strsafe.h>
 #include <tlhelp32.h>
 
+#include <cstdlib>
+
 #include "google_update_idl.h"
+#include "base/win/windows_version.h"
 
 namespace {
 
@@ -156,33 +159,10 @@
 bool IsChromeInstalled(HKEY root_key) {
   wchar_t version[64];
   size_t size = _countof(version);
-  if (ReadValueFromRegistry(root_key, kChromeRegClientsKey, kChromeRegVersion,
-                            version, &size))
-    return true;
-  return false;
+  return ReadValueFromRegistry(root_key, kChromeRegClientsKey,
+                               kChromeRegVersion, version, &size);
 }
 
-bool IsWinXPSp2OrLater(bool* is_vista_or_later) {
-  OSVERSIONINFOEX osviex = { sizeof(OSVERSIONINFOEX) };
-  int r = ::GetVersionEx((LPOSVERSIONINFO)&osviex);
-  // If this failed we're on Win9X or a pre NT4SP6 OS.
-  if (!r)
-    return false;
-
-  if (osviex.dwMajorVersion < 5)
-    return false;
-
-  if (osviex.dwMajorVersion > 5) {
-    *is_vista_or_later = true;
-    return true;    // way beyond Windows XP;
-  }
-
-  if (osviex.dwMinorVersion >= 1 && osviex.wServicePackMajor >= 2)
-    return true;    // Windows XP SP2 or better.
-
-  return false;     // Windows 2000, WinXP no Service Pack.
-}
-
 // Note this function should not be called on old Windows versions where these
 // Windows API are not available. We always invoke this function after checking
 // that current OS is Vista or later.
@@ -230,9 +210,8 @@
 
 bool IsRunningElevated() {
   // This method should be called only for Vista or later.
-  bool is_vista_or_later = false;
-  IsWinXPSp2OrLater(&is_vista_or_later);
-  if (!is_vista_or_later || !VerifyAdminGroup())
+  if ((base::win::GetVersion() < base::win::VERSION_VISTA) ||
+      !VerifyAdminGroup())
     return false;
 
   HANDLE process_token;
@@ -287,9 +266,11 @@
                                                         DWORD *reasons) {
   DWORD local_reasons = 0;
 
-  bool is_vista_or_later = false;
+  base::win::Version version = base::win::GetVersion();
   // System requirements?
-  if (!IsWinXPSp2OrLater(&is_vista_or_later))
+  if ((version < base::win::VERSION_XP) ||
+      ((version == base::win::VERSION_XP) &&
+       (base::win::OSInfo::GetInstance()->service_pack()[0] < 2)))
     local_reasons |= GCCC_ERROR_OSNOTSUPPORTED;
 
   if (IsChromeInstalled(HKEY_LOCAL_MACHINE))
@@ -300,7 +281,7 @@
 
   if (!VerifyHKLMAccess(kChromeRegClientsKey)) {
     local_reasons |= GCCC_ERROR_ACCESSDENIED;
-  } else if (is_vista_or_later && !VerifyAdminGroup()) {
+  } else if ((version >= base::win::VERSION_VISTA) && !VerifyAdminGroup()) {
     // For Vista or later check for elevation since even for admin user we could
     // be running in non-elevated mode. We require integrity level High.
     local_reasons |= GCCC_ERROR_INTEGRITYLEVEL;