If I were you, I'd follow one of these two ways:
1. Drop the ActionBar
If the main goal of this screen is to take a photo, users will most likely want to hold their devices in horizontal position. This will cause ActionBar to take up quite a lot of space, with very little of actual use to users.
The good example here is native Camera app (if I'm not mistaken since Jelly Bean). You can quickly jump to Gallery straight from Camera fragment just by swiping from right. Maybe this kind of behavior will do the job in your application.
Shortly: don't use ActionBar, use swipe right-left gesture to switch between camera and gallery
2. Transparent ActionBar
If for some reason you'd still like to use ActionBar (eg. pictures will be mostly taken in portrait orientation), make it transparent to let user see the biggest possible image.
Don't use split action bar as it would take up even more space.
Some links that you mi find useful:
Shortly: make ActionBar transparent and almost invisible to user
Hope it helped and I didn't do something wrong, as it is my first stackexchange answer.