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

chrome/browser/extensions/chrome_extensions_browser_client.cc

 // Copyright 2013 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/chrome_extensions_browser_client.h"
 
 #include "base/command_line.h"
 #include "base/version.h"
 #include "chrome/browser/app_mode/app_mode_utils.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 289 matching lines @@
 
 bool ChromeExtensionsBrowserClient::IsBackgroundUpdateAllowed() {
   return !base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableBackgroundNetworking);
 }
 
 bool ChromeExtensionsBrowserClient::IsMinBrowserVersionSupported(
     const std::string& min_version) {
   base::Version browser_version =
       base::Version(version_info::GetVersionNumber());
-  base::Version browser_min_version(min_version);
+  Version browser_min_version(min_version);
   if (browser_version.IsValid() && browser_min_version.IsValid() &&
       browser_min_version.CompareTo(browser_version) > 0) {
     return false;
   }
   return true;
 }
 
 ExtensionWebContentsObserver*
 ChromeExtensionsBrowserClient::GetExtensionWebContentsObserver(
     content::WebContents* web_contents) {
@@ skipping 43 matching lines @@
       // locations, and they must be ignored here.
       return;
 
     case VIEW_TYPE_INVALID:
       NOTREACHED();
       return;
   }
 }
 
 }  // namespace extensions