There are countless Aura entries in Google's Chromium revision blog, but there is not much information about it beyond a project page and the explanation that it will be a hardware accelerated UI. Google developer François Beaufort recently published videos on YouTube that provide a first look at Aura.
The video showcases an experimental feature that is only available in the Aura version of Chromium - translucent windows, which demos translucent window frames as well as constrained window dragging. Aura is still very much work in progress, but will enable Google to depart from GTK and decrease its reliance on Windows - and achieve much more UI code consistency across all supported platforms.
For the more immediate future, Google recently added a timeline feature in Chromium, which draws a graph of the data traffic sent and received by the browser. There is also a new flag, Pointer Lock, in the most recent nightly builds, which allows web applications to take over the mouse pointer to enhance web app functionality. A browser user can cancel such an action simply pressing the Escape key. A notable additions is also the chrome://sessions local URL, which displays all active tabs in Chrome - which works across multiple devices, if the live tab syncing feature is activated.