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

chrome/browser/platform_util_internal.h

Index: chrome/browser/platform_util_internal.h
diff --git a/chrome/browser/platform_util_internal.h b/chrome/browser/platform_util_internal.h
index 0b93b7dcddacfe74e6ce07729351ad10cdba45e0..90144c43049469a1cb0c9ed84cb3918b05f90c60 100644
--- a/chrome/browser/platform_util_internal.h
+++ b/chrome/browser/platform_util_internal.h
@@ -20,6 +20,12 @@ namespace internal {
 // Always called on the blocking pool.
 void PlatformOpenVerifiedItem(const base::FilePath& path, OpenItemType type);
 
+// Called by platform_util.cc on desktop platforms to invoke platform specific
+// logic to open the folder containing the item specified by |full_path| in the
+// desktop's default manner.
+void PlatformShowItemInFolder(Profile* profile,
+                              const base::FilePath& full_path);
+
 // Prevent shell or external applications from being invoked during testing.
 void DisableShellOperationsForTesting();