With commit a3d35af444 variable
itemInfo in js/ui/appDisplay.js was changed to a new object
(AppInfo from js/misc/appInfo.js) but some of the code in
js/ui/appDisplay.js wasn't updated accordingly. This commit
fixes that and makes the search box in the overlay usable
again.
This lets us share the recent-app-tracking, recent-file-tracking, and
icon-drawing code between the overlay and the sidebar, without the
sidebar having to poke into AppDisplayItem and DocDisplayItem's guts.