Bug 1042563 - [Homescreen] Implement performance startup events

https://bugzilla.mozilla.org/show_bug.cgi?id=1042563
After talking with @KevinGrandon, we are probably going to have to move the event later rather than earlier since there technically is a search bar located in the app and this will count as chrome. Also we aren't accounting for localization in this as well, so another reason this may get moved to later.