You might notice that Drafts, All Mail, Spam, and Trash are missing from the new layout, which probably means that the navigation bar scrolls. The reason why this might have leaked out has to do with the short time involved in putting together these presentations. In fact, the speaker giving the talk, Google's Jens Nagel, even accidentally included his real email address on the slide, which has been blotted out.
We have no time frame when to expect this redesigned version of Gmail for Android to get pushed out, but after taking a look at it we're sure everyone is thinking that the sooner the better.
source: AndroidPolice via electronista