Create a "GetWOW64Status()" utility function and make the rest of the codebas...

base/win/windows_version.h

-// Copyright (c) 2010 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.
 
 #ifndef BASE_WIN_WINDOWS_VERSION_H_
 #define BASE_WIN_WINDOWS_VERSION_H_
 #pragma once
 
+typedef void* HANDLE;
+
 namespace base {
 namespace win {
 
 // NOTE: Keep these in order so callers can do things like
 // "if (GetWinVersion() > WINVERSION_2000) ...".  It's OK to change the values,
 // though.
 enum Version {
   VERSION_PRE_2000 = 0,  // Not supported
   VERSION_2000 = 1,      // Not supported
   VERSION_XP = 2,
   VERSION_SERVER_2003 = 3,
   VERSION_VISTA = 4,
   VERSION_2008 = 5,
   VERSION_WIN7 = 6,
 };
 
 // Returns the running version of Windows.
 Version GetVersion();
 
 // Returns the major and minor version of the service pack installed.
 void GetServicePackLevel(int* major, int* minor);
 
+enum WOW64Status {

[rvargas (doing something else), 2011/03/04 00:12:18]

I would prefer if the enum was not a status (as in something that can change),
and instead the name was more "fixed"... this "is running under wow" or not, as
opposed to "disabled" which would always make me double check what it means. But
I don't have a real suggestion for a better name, so if you don't have a better
name that's ok.

[Peter Kasting, 2011/03/04 01:11:48]

Hmm.  I see your point.  I can't think of anything better though.  "WOW64State"
is equally bad.

+  WOW64_DISABLED,
+  WOW64_ENABLED,
+  WOW64_UNKNOWN,
+};
+
+// Returns whether this process is running under WOW64 (the wrapper that allows
+// 32-bit processes to run on 64-bit versions of Windows).  This will return
+// WOW64_DISABLED for both "32-bit Chrome on 32-bit Windows" and "64-bit Chrome
+// on 64-bit Windows".  WOW64_UNKNOWN means "an error occurred", e.g. the
+// process does not have sufficient access rights to determine this.
+WOW64Status GetWOW64Status();
+
+// Like GetWOW64Status(), but for the supplied handle instead of the current
+// process.
+WOW64Status GetWOW64StatusForProcess(HANDLE process_handle);
+
 }  // namespace win
 }  // namespace base
 
 #endif  // BASE_WIN_WINDOWS_VERSION_H_