Implement Windows GPO support for "dlpref" in component updater.

chrome/browser/extensions/updater/chrome_update_client_config.cc

 // Copyright 2015 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 "base/command_line.h"
 #include "base/version.h"
 #include "chrome/browser/component_updater/component_patcher_operation_out_of_process.h"
 #include "chrome/browser/extensions/updater/chrome_update_client_config.h"
 #include "chrome/browser/update_client/chrome_update_query_params_delegate.h"
 #include "chrome/common/channel_info.h"
@@ skipping 49 matching lines @@
 }
 
 std::string ChromeUpdateClientConfig::GetOSLongName() const {
   return impl_.GetOSLongName();
 }
 
 std::string ChromeUpdateClientConfig::ExtraRequestParams() const {
   return impl_.ExtraRequestParams();
 }
 
+std::string ChromeUpdateClientConfig::GetDownloadPreference() const {
+  return std::string();
+}
+
 net::URLRequestContextGetter* ChromeUpdateClientConfig::RequestContext() const {
   return impl_.RequestContext();
 }
 
 scoped_refptr<update_client::OutOfProcessPatcher>
 ChromeUpdateClientConfig::CreateOutOfProcessPatcher() const {
   return make_scoped_refptr(new component_updater::ChromeOutOfProcessPatcher);
 }
 
 bool ChromeUpdateClientConfig::DeltasEnabled() const {
   return impl_.DeltasEnabled();
 }
 
 bool ChromeUpdateClientConfig::UseBackgroundDownloader() const {
   return impl_.UseBackgroundDownloader();
 }
 
 ChromeUpdateClientConfig::~ChromeUpdateClientConfig() {}
 
 }  // namespace extensions