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

chrome/browser/extensions/extension_sync_data.cc

 // 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 "chrome/browser/extensions/extension_sync_data.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ skipping 218 matching lines @@
 
 bool ExtensionSyncData::PopulateFromExtensionSpecifics(
     const sync_pb::ExtensionSpecifics& specifics) {
   if (!crx_file::id_util::IdIsValid(specifics.id())) {
     LOG(ERROR) << "Attempt to sync bad ExtensionSpecifics (bad ID):\n"
                << GetExtensionSpecificsLogMessage(specifics);
     RecordBadSyncData(BAD_EXTENSION_ID);
     return false;
   }
 
-  base::Version specifics_version(specifics.version());
+  Version specifics_version(specifics.version());
   if (!specifics_version.IsValid()) {
     LOG(ERROR) << "Attempt to sync bad ExtensionSpecifics (bad version):\n"
                << GetExtensionSpecificsLogMessage(specifics);
     RecordBadSyncData(BAD_VERSION);
     return false;
   }
 
   // The update URL must be either empty or valid.
   GURL specifics_update_url(specifics.update_url());
   if (!specifics_update_url.is_empty() && !specifics_update_url.is_valid()) {
@@ skipping 80 matching lines @@
 
   if (entity_specifics.has_extension())
     return PopulateFromExtensionSpecifics(entity_specifics.extension());
 
   LOG(ERROR) << "Attempt to sync bad EntitySpecifics: no extension data.";
   RecordBadSyncData(NO_EXTENSION_SPECIFICS);
   return false;
 }
 
 }  // namespace extensions