Proposal: Make Accessibility Status known via DBus

Problem description: it is desireable to dynamically activate the accessibility framework. As an example this is helpful when the user uses a system for the first time, when the computer is shared with users that have no accessibility needs. The current status is that on Gnome the user has to enable accessibility in the settings and log out once to activate the accessibility framework.

Proposed solution: A dbus notification is sent to inform about the state of the accessibility framework. The enabled status of the accessibility framework can be queried via the same mechanism. Accessibility providers (AT-servers) listen to this signal. When they receive the notification, they start providing accessibility information and register as applications.

The DBus interface contains a property that says whether accessibility is enabled, has a notification signal and a method to enable accessibility.

A signal is sent from: org.freedesktop.Accessibility org.a11y.Bus org.a11y.XXXXXX

Proposed DBus interface:

<?xml version="1.0" encoding="UTF-8"?>
<node name="/node">
<interface name="org.a11y.atspi.FIXMEXXXXXXXXX">
  <property name="IsEnabled" type="b" access="read"/>

  <method name="Enable">
    <arg direction="in" name="enabled" type="b"/>
    <arg direction="out" type="b"/>
  </method>

  <signal name="NotifyAccessibilityEnabled">
    <arg name="enabled" type="b"/>
  </signal>
</interface>
</node>