[PATCH][CCLA] dijit.form.CheckBox - remove superfluous aria attributes

[mikeb]

dijit.form.CheckBox? has aria role="presentation" but uses aria-checked attribute. Aria-checked attribute is not a global aria attribute and can only be used on specific roles. To fix this I have decided it is best to remove the aria-checked attribute instead of changing the role to role=checkbox. This is because the WAI-ARIA spec states that WAI-ARIA should not be used as a replacement of normal HTML semantics.(​http://www.w3.org/TR/wai-aria/introduction#co-evolution)

Patch also updates the test pages for CheckBox? and Button (needed to check ToggleButton?)

[mikeb]

removes aria-checked attribute from dijit.form.Checkbox since it has no aria role; updates test pages; please proxy commy for michael billau ccla on file with IBM

[Douglas Hays]

mikeb, please test with the attached 16027.patch that adds role=checkbox to see if the violations are gone, and also check dojox/form/TriStateCheckBox since it inherits.

[Douglas Hays]

proposed fix with role=checkbox added plus TriStateCheckBox fixes

[mikeb]

doughays, I tested out the patch and it worked really well for CheckBox?. I had to make one slight change to TriStateCheckBox? (set _aria_attr: "aria-checked", because it was setting aria-pressed instead.) I also removed the aria-readonly from TriStateCheckbox? because that is invalid and updated the test page.

[mikeb]

set _aria_attr so that TriStateCheckbox? sets aria-checked, remove aria-readonly from TriStateCheckbox?, update test page

[Douglas Hays]

In [29816]:

Fixes #16027. Add role=checkbox/radio and aria-checked to CheckBox? and RadioButton? widgets.