It's the War Assets option.
Edit: Derp, I didn't read as much as I should've before replying. But redownload the trainer, the option is there.
[Edited by Shotgunmaniac, 4/3/2012 9:14:57 AM]
Yeah, I saw that. But see my edit for my previous post: Origin Retail trainer definitely has the option there.
Ah, yeah. Chrome tends to do that, I think it outright explodes in one way or another when you exceed a certain threshold in cache size rather than start doing the Firefox "if you don't take care of me I'll start eating your computer from the inside, starting with memory leaks" deal. But hey, at least Chrome doesn't start introducing new ways to cause memory leaks every time it updates!
As for a revision number system, simply spot check the "updated:" date for the trainer itself. It's also a good practice to just tick "track this title" on every game's page if you download a trainer for it. You automatically get an email whenever something is updated, which would've spared you a bit of trouble in this case most likely.