Add OS_CHROMEOS case in file_util::GetHomeDir()

base/chromeos/chromeos_version.h

 // 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.
 
 #ifndef BASE_CHROMEOS_CHROMEOS_VERSION_H_
 #define BASE_CHROMEOS_CHROMEOS_VERSION_H_
 
+#include <string>
+
 #include "base/base_export.h"
 
 namespace base {
 namespace chromeos {
 
 // Returns true if the browser is running on Chrome OS.
 // Useful for implementing stubs for Linux desktop.
 BASE_EXPORT bool IsRunningOnChromeOS();
 
+// Returns the home directory path, or an empty string if the home directory
+// is not found.
+BASE_EXPORT std::string GetHomeDirectory();
+
 }  // namespace chromeos
 }  // namespace base
 
 #endif  // BASE_CHROMEOS_CHROMEOS_VERSION_H_