Use DownloadItemModel for storing chrome/ specific UI data for DownloadItems.

chrome/browser/download/download_util.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.
 //
 // Download utilities.
 
 #ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UTIL_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UTIL_H_
 
 #include <string>
@@ skipping 180 matching lines @@
 
   CHROME_DOWNLOAD_SOURCE_LAST_ENTRY,
 };
 
 // Increment one of the above counts.
 void RecordDownloadCount(ChromeDownloadCountTypes type);
 
 // Record initiation of a download from a specific source.
 void RecordDownloadSource(ChromeDownloadSource source);
 
-// Check whether a download should be displayed in the download shelf.
-bool ShouldShowInShelf(content::DownloadItem* item);
-
-// Set whether a download should be displayed in the download shelf.
-void SetShouldShowInShelf(content::DownloadItem* item, bool should_show);
-
 }  // namespace download_util
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UTIL_H_