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

chrome/browser/ui/cocoa/download/download_item_controller.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.
 
 #import <Cocoa/Cocoa.h>
 
 #include <memory>
 
 #include "base/time/time.h"
 
@@ skipping 114 matching lines @@
 // Updates the UI and menu state from |downloadModel|.
 - (void)setStateFromDownload:(DownloadItemModel*)downloadModel;
 
 // Remove ourself from the download UI.
 - (void)remove;
 
 // Update item's visibility depending on if the item is still completely
 // contained in its parent.
 - (void)updateVisibility:(id)sender;
 
-// Called after a download is opened.
-- (void)downloadWasOpened;
+// Called after a download is opened or shown.
+- (void)downloadWasOpenedOrShown;
 
 // Asynchronous icon loading callback.
 - (void)setIcon:(NSImage*)icon;
 
 // Download item button clicked
 - (IBAction)handleButtonClick:(id)sender;
 
 // Returns the size this item wants to have.
 - (NSSize)preferredSize;
 
 // Returns the DownloadItem model object belonging to this item.
 - (content::DownloadItem*)download;
 
 // Returns the MenuModel for the download item context menu. The returned
 // MenuModel is owned by the DownloadItemController and will be valid until the
 // DownloadItemController is destroyed.
 - (ui::MenuModel*)contextMenuModel;
 
 // Updates the tooltip with the download's path.
 - (void)updateToolTip;
 
 // Handling of dangerous downloads
 - (void)clearDangerousMode;
 - (BOOL)isDangerousMode;
 - (IBAction)saveDownload:(id)sender;
 - (IBAction)discardDownload:(id)sender;
 - (IBAction)showContextMenu:(id)sender;
 
 @end