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

content/public/test/mock_download_item.cc

Index: content/public/test/mock_download_item.cc
diff --git a/content/public/test/mock_download_item.cc b/content/public/test/mock_download_item.cc
index 7b19c3195401c978600d92a8765c49f77202cafb..ba5d6814cb30d0610594e7a144a95fff5031849f 100644
--- a/content/public/test/mock_download_item.cc
+++ b/content/public/test/mock_download_item.cc
@@ -26,6 +26,11 @@ void MockDownloadItem::NotifyObserversDownloadOpened() {
     observer.OnDownloadOpened(this);
 }
 
+void MockDownloadItem::NotifyObserversDownloadShown() {
+  for (auto& observer : observers_)
+    observer.OnDownloadShown(this);
+}
+
 void MockDownloadItem::NotifyObserversDownloadRemoved() {
   for (auto& observer : observers_)
     observer.OnDownloadRemoved(this);