Comment 7 for bug 857153

Currently, Firefox determines that accessibility is enabled if GNOME_ACCESSIBILITY is set to 1 in the environment or if /desktop/gnome/interface/accessibility is set to True in gconf. The latter check successfully determines whether accessibility is enabled for GNOME 2 but not for GNOME 3. Currently, a distribution would need to, ie, patch the firefox loader script to set GNOME_ACCESSIBILITY=1 for Firefox to be accessible under GNOME 3.

There is now a gsettings key (toolkit-accessibility in the org.gnome.desktop.interface schema), but this is specific to GNOME, and so using it may not be optimal with AT-SPI becoming usable in XFCE and eventually KDE. In order to handle this, the AT-SPI bus launcher (org.a11y.Bus) has a org.a11y.Status.IsEnabled property on the bus object (/org/a11y/bus). Under GNOME, this is a proxy for the GSettings key. Xfce will likely have code in the future to ensure that this property is set correctly. I would recommend that Firefox should check this property first, falling back to gconf if there is an error checking the property, but I'm not sure how best to handle this in the code. Currently, there is a system pref (config.use_system_prefs.accessibility) which maps to the gconf key. There is also code in several places that checks the value of GNOME_ACCESSIBILITY. So I guess we want to somehow have custom handling for this system prefernce, if that is doable, or write a function somewhere to test whether a11y is enabled (making the D-Bus call and falling back to checking the system pref on error) and use that in the places where it is needed to check the state of accessibility.

Advice welcome.