1800994 - Modify combobox accessible value logic to better match the ARIA spec

Status: NEW

(Core :: Disability Access APIs, task)

Description

[Nathan LaPré]

The ARIA spec for combobox says:

User agents MUST expose the value of elements with role combobox to assistive technologies. The value of a combobox is represented by one of the following:

• If the combobox element is a host language element that provides a value, such as an HTML input element, the value of the combobox is the value of that element.
• Otherwise, the value of the combobox is represented by its descendant elements and can be determined using the same method used to compute the name of a button from its descendant content.

Meanwhile, the existing code takes a bit of a different approach, searching instead for the first selected option child in LocalAccessible and in RemoteAccessibleBase.

(note that the above behavior will change slightly with this revision, which more or less implements the 2nd bullet point from the spec, but the core issue reported here remains)

I think that we should hew more closely to the spec by removing the option selection code and instead implementing checks for specific html elements. My hope is that this won't break tons of tests and expectations.