Created an interface for DownloadFile, 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 109 matching lines @@
   void RenameCompletingDownloadFile(DownloadId id,
                                     const FilePath& full_path,
                                     bool overwrite_existing_file);
 
   // The number of downloads currently active on the DownloadFileManager.
   // Primarily for testing.
   int NumberOfActiveDownloads() const {
     return downloads_.size();
   }
 
+ protected:
+   // Creates a new DownloadFile.
+   // Used only for testing, to create a MockDownloadFile instead.
+  DownloadFile* NewDownloadFile(
+      DownloadCreateInfo* info,
+      const DownloadRequestHandle& request_handle,
+      DownloadManager* download_manager);

[Randy Smith (Not in Mondays), 2011/11/10 21:58:43]

I don't think that this is used in this CL?  I don't think I have objections to
it, but I'd like to see it combined with its use cases to judge that.  Willing
to pull it out and put it in in the first CL that uses it?

[ahendrickson, 2011/11/13 00:50:21]

Done.

+
  private:
   friend class base::RefCountedThreadSafe<DownloadFileManager>;
   friend class DownloadManagerTest;
   FRIEND_TEST_ALL_PREFIXES(DownloadManagerTest, StartDownload);
 
   ~DownloadFileManager();
 
   // Timer helpers for updating the UI about the current progress of a download.
   void StartUpdateTimer();
   void StopUpdateTimer();
@@ skipping 29 matching lines @@
   // 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_