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

chrome/browser/process_singleton.h

 // 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 CHROME_BROWSER_PROCESS_SINGLETON_H_
 #define CHROME_BROWSER_PROCESS_SINGLETON_H_
 #pragma once
 
 #include "build/build_config.h"
 
@@ skipping 60 matching lines @@
   // Exposed for testing.  We use a timeout on Linux, and in tests we want
   // this timeout to be short.
   NotifyResult NotifyOtherProcessWithTimeout(const CommandLine& command_line,
                                              int timeout_seconds,
                                              bool kill_unresponsive);
   NotifyResult NotifyOtherProcessWithTimeoutOrCreate(
       const CommandLine& command_line,
       int timeout_seconds);
 #endif  // defined(OS_LINUX)
 
-#if defined(OS_WIN)
+#if defined(OS_WIN) && !defined(USE_AURA)
   // Used in specific cases to let us know that there is an existing instance
   // of Chrome running with this profile. In general, you should not use this
   // function. Instead consider using NotifyOtherProcessOrCreate().
   // For non profile-specific method, use
   // browser_util::IsBrowserAlreadyRunning().
   bool FoundOtherProcessWindow() const {
       return (NULL != remote_window_);
   }
 #endif  // defined(OS_WIN)
 
@@ skipping 85 matching lines @@
   // File descriptor associated with the lockfile, valid between
   // |Create()| and |Cleanup()|.  Two instances cannot have a lock on
   // the same file at the same time.
   int lock_fd_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ProcessSingleton);
 };
 
 #endif  // CHROME_BROWSER_PROCESS_SINGLETON_H_