Fix the fileListingHelper template function specialisation

The WebContentsAdapter::filesSelectedInChooser function parameter type
has been changed since the Chromium update.
Thus content::FileChooserFileInfo has to be used instead of ui::SelectedFileInfo.

Change-Id: Ia6a50409f3f7c704228cb739fc50d694e633dbee
Reviewed-by: Andras Becsi <andras.becsi@theqtcompany.com>