Implement CUP signing in UpdateClient.

components/update_client/configurator.h

 // Copyright 2014 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_UPDATE_CLIENT_CONFIGURATOR_H_
 #define COMPONENTS_UPDATE_CLIENT_CONFIGURATOR_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 80 matching lines @@
   virtual scoped_refptr<update_client::OutOfProcessPatcher>
   CreateOutOfProcessPatcher() const = 0;
 
   // True means that this client can handle delta updates.
   virtual bool DeltasEnabled() const = 0;
 
   // True means that the background downloader can be used for downloading
   // non on-demand components.
   virtual bool UseBackgroundDownloader() const = 0;
 
+  // True if signing of update checks is enabled.
+  virtual bool UseCupSigning() const = 0;
+
   // Gets a task runner to a blocking pool of threads suitable for worker jobs.
   virtual scoped_refptr<base::SequencedTaskRunner> GetSequencedTaskRunner()
       const = 0;
 
  protected:
   friend class base::RefCountedThreadSafe<Configurator>;
 
   virtual ~Configurator() {}
 };
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_CONFIGURATOR_H_