Add initial Controller to DownloadService

components/download/internal/download_driver.h

 // Copyright 2017 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_DOWNLOAD_INTERNAL_DOWNLOAD_DRIVER_H_
 #define COMPONENTS_DOWNLOAD_INTERNAL_DOWNLOAD_DRIVER_H_
 
 #include <string>
 
 #include "base/optional.h"
@@ skipping 28 matching lines @@
     virtual void OnDownloadFailed(const DriverEntry& download, int reason) = 0;
 
     // Called when any download is successfully completed.
     virtual void OnDownloadSucceeded(const DriverEntry& download,
                                      const base::FilePath& path) = 0;
 
     // Called when any download is updated.
     virtual void OnDownloadUpdated(const DriverEntry& download) = 0;
   };
 
+  virtual ~DownloadDriver() = default;
+
   // Initialize the driver to receive download updates.
   virtual void Initialize(Client* client) = 0;
 
   // Returns if the driver is ready. Returns false when the driver is not
   // initialized by the client, or low level download library has been shut
   // down.
   virtual bool IsReady() const = 0;
 
   // Starts a new download.
   virtual void Start(const DownloadParams& params) = 0;
 
   // Cancels an existing download, all data associated with this download should
   // be removed.
   virtual void Cancel(const std::string& guid) = 0;
 
   // Pauses the download.
   virtual void Pause(const std::string& guid) = 0;
 
   // Resumes the download
   virtual void Resume(const std::string& guid) = 0;
 
   // Find a download record from low level download library.
   virtual base::Optional<DriverEntry> Find(const std::string& guid) = 0;
 };
 
 }  // namespace download
 
 #endif  // COMPONENTS_DOWNLOAD_INTERNAL_DOWNLOAD_DRIVER_H_