Get Chrome to build & link with USE_AURA on Windows again.

chrome/browser/process_singleton_aura.cc

 // 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.
 
 #include "chrome/browser/process_singleton.h"
 
 // Look for a Chrome instance that uses the same profile directory.
 ProcessSingleton::ProcessSingleton(const FilePath& user_data_dir)
     :
-#if defined(OS_WIN)
+#if defined(OS_WIN) && !defined(USE_AURA)
     window_(NULL),
 #endif
     locked_(false), foreground_window_(NULL) {
 }
 
 ProcessSingleton::~ProcessSingleton() {
 }
 
 ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcess() {
   // TODO(beng):
@@ skipping 10 matching lines @@
 bool ProcessSingleton::Create() {
   // TODO(beng):
   NOTIMPLEMENTED();
   return true;
 }
 
 void ProcessSingleton::Cleanup() {
   // TODO(beng):
   NOTIMPLEMENTED();
 }