Re: [orca-list] Accessibility of Chromium / Google Chrome

[Dominic Mazzoni <dmazzoni google com>]

On Tue, Aug 16, 2011 at 3:58 AM, Mario Sanchez Prada
<msanchez igalia com> wrote:
> > Unfortunately, Chrome does not use the GTK+ port of Webkit, and there
> > are technical reasons why it's not possible for us to use that code
> > directly, so we'd have to rewrite most of that code.
>
> Just out of curiosity, I'd like to know (as far as it's possible) some
> details about why it was not possible.

For security, Chromium creates a separate renderer process for each
tab you have open. These processes each run their own instance of
WebKit but they're completely sandboxed so they can't access the
operating system - they just receive events from Chromium's main
process and send back bitmaps and other metadata. So Chromium's
renderer processes don't use a platform-specific port of WebKit, they
use a special Chromium port, that shuttles the rendered webpage,
including accessibility data, back to the main process securely. It
sounds cumbersome but it's actually very fast and efficient, and the
total isolation means that it's very hard for a bug in the code
running in one tab to result in a security vulnerability.

> I know how to build WK (at least the gtk port) and also the chromium
> browser on my Linux machine (ideally a release build, dynamically linked
> -otherwise I usually find problems), as well as ORCA and the ATK/AT-SPI
> needs, so I think I could help on this too, whenever time permits :-)

That's great! I'm glad to see there are so many people on this list
who will be able to try things out at the source level, that should
make it a lot easier.

- Dominic