Revert of base: Remove using:: declaration from version.h header.

chrome/installer/util/google_update_settings.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 CHROME_INSTALLER_UTIL_GOOGLE_UPDATE_SETTINGS_H_
 #define CHROME_INSTALLER_UTIL_GOOGLE_UPDATE_SETTINGS_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 253 matching lines @@
   static bool ReenableAutoupdates();
 
   // Records UMA stats about Chrome's update policy.
   static void RecordChromeUpdatePolicyHistograms();
 
   // Returns Google Update's uninstall command line, or an empty string if none
   // is found.
   static base::string16 GetUninstallCommandLine(bool system_install);
 
   // Returns the version of Google Update that is installed.
-  static base::Version GetGoogleUpdateVersion(bool system_install);
+  static Version GetGoogleUpdateVersion(bool system_install);
 
   // Returns the time at which Google Update last started an automatic update
   // check, or the null time if this information isn't available.
   static base::Time GetGoogleUpdateLastStartedAU(bool system_install);
 
   // Returns the time at which Google Update last successfully contacted Google
   // servers and got a valid check response, or the null time if this
   // information isn't available.
   static base::Time GetGoogleUpdateLastChecked(bool system_install);
 
@@ skipping 29 matching lines @@
   // this will do nothing to |experiment_labels|. This will return true if the
   // label did not exist, or was successfully read.
   static bool ReadExperimentLabels(bool system_install,
                                    base::string16* experiment_labels);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(GoogleUpdateSettings);
 };
 
 #endif  // CHROME_INSTALLER_UTIL_GOOGLE_UPDATE_SETTINGS_H_