Update all users of base::Version to explicitly specify the namespace, and clean up the header.

extensions/common/extension.cc

 // Copyright (c) 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 "extensions/common/extension.h"
 
 #include "base/base64.h"
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 572 matching lines @@
   name_ = UTF16ToUTF8(localized_name);
   return true;
 }
 
 bool Extension::LoadVersion(base::string16* error) {
   std::string version_str;
   if (!manifest_->GetString(keys::kVersion, &version_str)) {
     *error = ASCIIToUTF16(errors::kInvalidVersion);
     return false;
   }
-  version_.reset(new Version(version_str));
+  version_.reset(new base::Version(version_str));
   if (!version_->IsValid() || version_->components().size() > 4) {
     *error = ASCIIToUTF16(errors::kInvalidVersion);
     return false;
   }
   return true;
 }
 
 bool Extension::LoadAppFeatures(base::string16* error) {
   if (!LoadExtent(keys::kWebURLs, &extent_,
                   errors::kInvalidWebURLs, errors::kInvalidWebURL, error)) {
@@ skipping 183 matching lines @@
 
 UpdatedExtensionPermissionsInfo::UpdatedExtensionPermissionsInfo(
     const Extension* extension,
     const PermissionSet* permissions,
     Reason reason)
     : reason(reason),
       extension(extension),
       permissions(permissions) {}
 
 }   // namespace extensions