Customize Preview Page

Hi, just came across this workflow idea in WP.

Is it possible to add a shortcode/widget/publish button on the preview page so that users can straight away approve the page instead of returning to the page editor to publish? If can how and where do I insert this code?

Let say we are using Oasis workflow, an email is send to relative users to view the updated content in the preview page then use can just approve the change from there.