ACTION-2064: The ATK/AT-SPI2 mappings for aria-readonly need to be updated.

From https://developer.gnome.org/atk/unstable/atk-AtkState.html#AtkStateType:

ATK_STATE_EDITABLE
Indicates that this object can contain text, and that the user can change the textual contents of this object by editing those contents directly. For an object which is expected to be editable due to its type, but which cannot be edited due to the application or platform preventing the user from doing so, that object's AtkStateSet should lack ATK_STATE_EDITABLE and should contain ATK_STATE_READ_ONLY.

ATK_STATE_READ_ONLY
Indicates that a widget which is ENABLED and SENSITIVE has a value which can be read, but not modified, by the user. Note that this state should only be applied to widget types whose value is normally directly user modifiable, such as check boxes, radio buttons, spin buttons, text input fields, and combo boxes, as a means to convey that the expected interaction with that widget is not possible. When the expected interaction with a widget does not include modification by the user, as is the case with labels and containers, ATK_STATE_READ_ONLY should not be applied. See also ATK_STATE_EDITABLE. Since : ATK-2-16


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The mapping in the Core AAM for aria-readonly="true" on ATK/AT-SPI2 is "Not Mapped"; it should instead be STATE_READ_ONLY, along with a similar inheritance statement for gridcell that all the other platforms have.

The mapping in the Core AAM for aria-readonly="false" on ATK/AT-SPI2 is to STATE_EDITABLE. That is correct for text controls; not for other widget types.

Closing as per AAPI meeting 15-Nov-2016.