No need to pass DownloadItemModel ownership.

chrome/browser/download/test_download_shelf.h

 // Copyright (c) 2012 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 CHROME_BROWSER_DOWNLOAD_TEST_DOWNLOAD_SHELF_H_
 #define CHROME_BROWSER_DOWNLOAD_TEST_DOWNLOAD_SHELF_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chrome/browser/download/download_shelf.h"
 
 // An implementation of DownloadShelf for testing.
 class TestDownloadShelf : public DownloadShelf {
  public:
   TestDownloadShelf();
   virtual ~TestDownloadShelf();
 
   // DownloadShelf:
 
   virtual bool IsShowing() const OVERRIDE;
   virtual bool IsClosing() const OVERRIDE;
   virtual Browser* browser() const OVERRIDE;
 
  protected:
-  virtual void DoAddDownload(DownloadItemModel* download_model) OVERRIDE;
+  virtual void DoAddDownload(content::DownloadItem* download) OVERRIDE;
   virtual void DoShow() OVERRIDE;
   virtual void DoClose() OVERRIDE;
 
  private:
   bool is_showing_;
 
   DISALLOW_COPY_AND_ASSIGN(TestDownloadShelf);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_TEST_DOWNLOAD_SHELF_H_