This is an update of our Aura plans first explained in [1] and then in [2]. Please read those if you don't know what Aura is.
At that point we didn't have a timeline but now we do. We are trying to ship Aura on Windows in m32. The main issue is performance but we are making fast progress towards parity on that front. As in any release we are metrics driven; if we don't meet the speed, stability, security metrics we simply don't ship.
Aura is a grand unification of our graphics and UI stack that has significant implications. Here are the ones that you want to be aware of:
1- For Win7 and Win8 machines with capable video hardware and relatively new drivers, Aura fully uses the GPU.
This might lead to issues for some users with non standard configurations. We are increasing the test efforts to include varied hardware but we don't expect to catch every bug.
2- For WinXP and Vista users we will always use the software-only path.
A lot of the performance work we are doing is related to make this mode as fast as it is in m31. However, in the short term we expect to use more CPU cycles and more memory than m31. Part of it is just a trade-off between scrolling performance and use of resources. We'll work to refine our stack in upcoming releases so we only pay the price for the things we really care about.
3- We have an automatic mechanism to switch Chrome from the GPU path to software path if we detect trouble.
It is nearly instantaneous in the case where the GPU process crashes. However, if the GPU process hangs it takes longer for Chrome to detect this condition, and of course BSODs are not something that we can prevent in most cases.
4- Opt-in or out.
In the short term users can opt-in or out from GPU acceleration from the settings menu -> system -> Use hardware acceleration. This setting will go away for XP and Vista users
once we switch to use DX11 because that is not available on those releases. We don't have a timeline for that yet.
5- WebGL and Pepper Flash.
If Aura is in software mode (for XP users for example) both WebGL and Pepper flash are also in software mode. This means that Flash's stage 3D [3] is unavailable. In previous versions of Chrome we could tolerate some parts of the page using hardware acceleration and others not using it but that is not practical with Aura. In the case of Flash the user can switch to NPAPI flash (for now, NPAPI is going away by the end of 2014) or Opt-in into hardware acceleration.
6- Windows 8 mode and Ash.
Ash is the Aura Shell [4]. Which most people know as the ChromeOS windowing environment. Aura implies Ash, so we decided to use Ash as our shell environment for Windows 8 metro mode. We are currently experimenting on how much of the shell we expose in Windows 8 mode, but even if Chrome m32 looks like m31 in metro mode Ash will still be running under the covers.
7- Linux and Mac.
The plan of record is to move Linux Chrome to Aura in m33. There are no plans to move Mac to Aura.
8- Legacy UI/ Graphics stack.
It will be removed from the codebase once there are no clients . If the current plans hold, it means it will be removed before we branch for m34.
-cpu