Download shelf autohides on showing in shell, just same as regular open

chrome/browser/ui/views/download/download_item_view.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.
 //
 // A ChromeView that implements one download on the Download shelf.
 // Each DownloadItemView contains an application icon, a text label
 // indicating the download's file name, a text label indicating the
 // download's status (such as the number of bytes downloaded so far)
 // and a button for canceling an in progress download, or opening
 // the completed download.
@@ skipping 55 matching lines @@
   // IconManager::Client interface.
   void OnExtractIconComplete(gfx::Image* icon);
 
   // Returns the DownloadItem model object belonging to this item.
   content::DownloadItem* download() { return model_.download(); }
 
   // DownloadItem::Observer methods
   virtual void OnDownloadUpdated(content::DownloadItem* download) OVERRIDE;
   virtual void OnDownloadOpened(content::DownloadItem* download) OVERRIDE;
   virtual void OnDownloadDestroyed(content::DownloadItem* download) OVERRIDE;
+  virtual void OnDownloadShown(content::DownloadItem* download) OVERRIDE;
 
   // Overridden from views::View:
   virtual void Layout() OVERRIDE;
   virtual gfx::Size GetPreferredSize() OVERRIDE;
   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
   virtual bool OnMouseDragged(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseCaptureLost() OVERRIDE;
   virtual void OnMouseMoved(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseExited(const ui::MouseEvent& event) OVERRIDE;
@@ skipping 250 matching lines @@
 
   // The icon loaded in the download shelf is based on the file path of the
   // item.  Store the path used, so that we can detect a change in the path
   // and reload the icon.
   base::FilePath last_download_item_path_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemView);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_DOWNLOAD_DOWNLOAD_ITEM_VIEW_H__