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

chrome/browser/ui/cocoa/download/download_item_controller.h

Index: chrome/browser/ui/cocoa/download/download_item_controller.h
diff --git a/chrome/browser/ui/cocoa/download/download_item_controller.h b/chrome/browser/ui/cocoa/download/download_item_controller.h
index 78010b6be04b3c4056ba92fcfbb2039ce396ba65..a255e829d91130c2fec693057d32ba6ecb49a594 100644
--- a/chrome/browser/ui/cocoa/download/download_item_controller.h
+++ b/chrome/browser/ui/cocoa/download/download_item_controller.h
@@ -91,6 +91,9 @@ class MenuModel;
 // Called after a download is opened.
 - (void)downloadWasOpened;
 
+// Called after a download is shown in shell.
+- (void)downloadWasShown;
+
 // Asynchronous icon loading callback.
 - (void)setIcon:(NSImage*)icon;
 
@@ -103,6 +106,9 @@ class MenuModel;
 // Returns the DownloadItem model object belonging to this item.
 - (content::DownloadItem*)download;
 
+// Returns the DownloadItemModel object belonging to this item.
+- (DownloadItemModel*)downloadItemModel;
+
 // 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.