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

components/component_updater/configurator_impl.h

 // 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.
 
 #ifndef COMPONENTS_COMPONENT_UPDATER_CONFIGURATOR_IMPL_H_
 #define COMPONENTS_COMPONENT_UPDATER_CONFIGURATOR_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 49 matching lines @@
   base::Version GetBrowserVersion() const;
 
   // Returns the OS's long name like "Windows", "Mac OS X", etc.
   std::string GetOSLongName() const;
 
   // Parameters added to each url request. It can be empty if none are needed.
   // The return string must be safe for insertion as an attribute in an
   // XML element.
   std::string ExtraRequestParams() const;
 
+  // Provides a hint for the server to control the order in which multiple
+  // download urls are returned.
+  std::string GetDownloadPreference() const;
+
   // The source of contexts for all the url requests.
   net::URLRequestContextGetter* RequestContext() const;
 
   // True means that this client can handle delta updates.
   bool DeltasEnabled() const;
 
   // True means that the background downloader can be used for downloading
   // non on-demand components.
   bool UseBackgroundDownloader() const;
 
@@ skipping 11 matching lines @@
   bool deltas_enabled_;
   bool background_downloads_enabled_;
   bool fallback_to_alt_source_url_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(ConfiguratorImpl);
 };
 
 }  // namespace component_updater
 
 #endif  // COMPONENTS_COMPONENT_UPDATER_CONFIGURATOR_IMPL_H_