Created a DownloadManager interface, for use in unit tests..

content/browser/download/download_file_manager.h

 // Copyright (c) 2011 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.
 //
 // The DownloadFileManager owns a set of DownloadFile objects, each of which
 // represent one in progress download and performs the disk IO for that
 // download. The DownloadFileManager itself is a singleton object owned by the
 // ResourceDispatcherHost.
 //
 // The DownloadFileManager uses the file_thread for performing file write
@@ skipping 39 matching lines @@
 #include "base/timer.h"
 #include "content/browser/download/download_id.h"
 #include "content/browser/download/interrupt_reasons.h"
 #include "content/common/content_export.h"
 #include "net/base/net_errors.h"
 #include "ui/gfx/native_widget_types.h"
 
 struct DownloadCreateInfo;
 struct DownloadSaveInfo;
 class DownloadFile;
-class DownloadManager;
+class DownloadManagerInterface;
 class DownloadRequestHandle;
 class FilePath;
 class GURL;
 class ResourceDispatcherHost;
 
 namespace content {
 class DownloadBuffer;
 }
 
 namespace net {
@@ skipping 28 matching lines @@
 
   // Handlers for notifications sent from the UI thread and run on the
   // FILE thread.  These are both terminal actions with respect to the
   // download file, as far as the DownloadFileManager is concerned -- if
   // anything happens to the download file after they are called, it will
   // be ignored.
   void CancelDownload(DownloadId id);
   void CompleteDownload(DownloadId id);
 
   // Called on FILE thread by DownloadManager at the beginning of its shutdown.
-  void OnDownloadManagerShutdown(DownloadManager* manager);
+  void OnDownloadManagerShutdown(DownloadManagerInterface* manager);
 
   // The DownloadManager in the UI thread has provided an intermediate
   // .crdownload name for the download specified by |id|.
   void RenameInProgressDownloadFile(DownloadId id, const FilePath& full_path);
 
   // The DownloadManager in the UI thread has provided a final name for the
   // download specified by |id|.
   // |overwrite_existing_file| prevents uniquification, and is used for SAFE
   // downloads, as the user may have decided to overwrite the file.
   // Sent from the UI thread and run on the FILE thread.
@@ skipping 19 matching lines @@
   void StopUpdateTimer();
   void UpdateInProgressDownloads();
 
   // Clean up helper that runs on the download thread.
   void OnShutdown();
 
   // Creates DownloadFile on FILE thread and continues starting the download
   // process.
   void CreateDownloadFile(DownloadCreateInfo* info,
                           const DownloadRequestHandle& request_handle,
-                          DownloadManager* download_manager,
+                          DownloadManagerInterface* download_manager,
                           bool hash_needed);
 
   // Called only on the download thread.
   DownloadFile* GetDownloadFile(DownloadId global_id);
 
   // Called only from RenameInProgressDownloadFile and
   // RenameCompletingDownloadFile on the FILE thread.
   // |rename_error| indicates what error caused the cancel.
   void CancelDownloadOnRename(DownloadId global_id, net::Error rename_error);
 
   // Erases the download file with the given the download |id| and removes
   // it from the maps.
   void EraseDownload(DownloadId global_id);
 
   typedef base::hash_map<DownloadId, DownloadFile*> DownloadFileMap;
 
   // A map of all in progress downloads.  It owns the download files.
   DownloadFileMap downloads_;
 
   // Schedule periodic updates of the download progress. This timer
   // is controlled from the FILE thread, and posts updates to the UI thread.
   base::RepeatingTimer<DownloadFileManager> update_timer_;
 
   ResourceDispatcherHost* resource_dispatcher_host_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFileManager);
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_MANAGER_H_