Remove obsolete chromeos specific code

chrome/app/chrome_exe_main_gtk.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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 "build/build_config.h"
 #include "chrome/browser/first_run/upgrade_util.h"
 
 // The entry point for all invocations of Chromium, browser and renderer. On
 // windows, this does nothing but load chrome.dll and invoke its entry point in
 // order to make it easy to update the app from GoogleUpdate. We don't need
 // that extra layer with on linux.
 
 extern "C" {
 int ChromeMain(int argc, const char** argv);
 }
 
 int main(int argc, const char** argv) {
   int return_code = ChromeMain(argc, argv);
 
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+#if defined(OS_LINUX)
   // Launch a new instance if we're shutting down because we detected an
   // upgrade in the persistent mode.
   upgrade_util::RelaunchChromeBrowserWithNewCommandLineIfNeeded();
 #endif
 
   return return_code;
 }