async-tasks-impl: Adding refreshBehavior in ProgressButton ctor if task ...

...container already running:

If a user starts a long running task and leaves the page with the ProgressButton, when coming back to the page again, the ProgressButton should showing and updating the current progress. I tried to implement this by passing the already running task container to the ProgressButton when the page is re-created. This, however, doesn't work since the ProgressButton implementation doesn't add the refresh behavior to the button in the ctor. This patch could fix this behavior.