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

chrome/browser/download/all_download_item_notifier.cc

 // 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.
 
 #include "chrome/browser/download/all_download_item_notifier.h"
 
 AllDownloadItemNotifier::AllDownloadItemNotifier(
     content::DownloadManager* manager,
     AllDownloadItemNotifier::Observer* observer)
     : manager_(manager),
@@ skipping 44 matching lines @@
 void AllDownloadItemNotifier::OnDownloadOpened(
     content::DownloadItem* item) {
   observer_->OnDownloadOpened(manager_, item);
 }
 
 void AllDownloadItemNotifier::OnDownloadRemoved(
     content::DownloadItem* item) {
   observer_->OnDownloadRemoved(manager_, item);
 }
 
+void AllDownloadItemNotifier::OnDownloadShown(
+    content::DownloadItem* item) {
+  observer_->OnDownloadShown(manager_, item);
+}
+
 void AllDownloadItemNotifier::OnDownloadDestroyed(
     content::DownloadItem* item) {
   item->RemoveObserver(this);
   observing_.erase(item);
 }