Summary:
Both export methods behaved slightly differently:
* Export to file returned earlier when running in background, which skiped the tracking of export termination;
* Share link always showed notification, even when on foreground;
* Share link status "hanged" - the share was never unset.
This change makes both consistent:
* Always track export finish - whether its in foreground or background;
* Only show notificaiton if running in background;
* Always reset the share/status.
On top of this it also:
* Normalizes the screenshot status to terminate in '...' as all the others;
* Only copies export URL to clipboard when exporting link if running in the background.
Reviewed By: passy
Differential Revision: D21425095
fbshipit-source-id: 9864a63269df6bd05ab065ff0e5d9f17b9ac6db6
64deaee5a7