Refactoring DownloadManager::DownloadURL to add proper annotation.

components/download/content/download_driver_impl.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_CONTENT_DOWNLOAD_DRIVER_IMPL_H_
 #define COMPONENTS_DOWNLOAD_CONTENT_DOWNLOAD_DRIVER_IMPL_H_
 
 #include <string>
 
 #include "base/files/file_path.h"
 #include "components/download/internal/download_driver.h"
 #include "components/download/public/download_params.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/download_manager.h"
+#include "net/traffic_annotation/network_traffic_annotation.h"
 
 namespace download {
 
 struct DriverEntry;
 
 // Aggregates and handles all interaction between download service and content
 // download logic.
 class DownloadDriverImpl : public DownloadDriver,
                            public content::DownloadManager::Observer,
                            public content::DownloadItem::Observer {
  public:
   // Creates a driver entry based on a download item.
   static DriverEntry CreateDriverEntry(const content::DownloadItem* item);
 
   // Create the driver. All files downloaded will be saved to |dir|.
   DownloadDriverImpl(content::DownloadManager* manager,
                      const base::FilePath& dir);
   ~DownloadDriverImpl() override;
 
   // DownloadDriver implementation.
   void Initialize(DownloadDriver::Client* client) override;
   bool IsReady() const override;
-  void Start(const DownloadParams& params) override;
+  void Start(
+      const DownloadParams& params,
+      const net::NetworkTrafficAnnotationTag& traffic_annotation) override;
   void Cancel(const std::string& guid) override;
   void Pause(const std::string& guid) override;
   void Resume(const std::string& guid) override;
   base::Optional<DriverEntry> Find(const std::string& guid) override;
 
  private:
   // content::DownloadItem::Observer implementation.
   void OnDownloadUpdated(content::DownloadItem* item) override;
 
   // content::DownloadManager::Observer implementation.
@@ skipping 10 matching lines @@
 
   // The client that receives updates from low level download logic.
   DownloadDriver::Client* client_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadDriverImpl);
 };
 
 }  // namespace download
 
 #endif  // COMPONENTS_DOWNLOAD_CONTENT_DOWNLOAD_DRIVER_IMPL_H_