Bug 1725916: Ensure an Accessible is created if aria-description is set. r=eeejay

Differential Revision: https://phabricator.services.mozilla.com/D122850

accessible/base/ARIAMap.cpp

@@ -1343,6 +1343,12 @@ static const AttrCharacteristics gWAIUnivAttrMap[] = {
   {nsGkAtoms::aria_controls,          ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
   {nsGkAtoms::aria_current,  ATTR_BYPASSOBJ_IF_FALSE | ATTR_VALTOKEN | ATTR_GLOBAL },
   {nsGkAtoms::aria_describedby,       ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
+  // XXX Ideally, aria-description shouldn't expose a description object
+  // attribute (i.e. it should have ATTR_BYPASSOBJ). However, until the
+  // description-from attribute is implemented (bug 1726087), clients such as
+  // NVDA depend on the description object attribute to work out whether the
+  // accDescription originated from aria-description.
+  {nsGkAtoms::aria_description,                                        ATTR_GLOBAL },
   {nsGkAtoms::aria_details,           ATTR_BYPASSOBJ                 | ATTR_GLOBAL },
   {nsGkAtoms::aria_disabled,          ATTR_BYPASSOBJ | ATTR_VALTOKEN | ATTR_GLOBAL },
   {nsGkAtoms::aria_dropeffect,                         ATTR_VALTOKEN | ATTR_GLOBAL },

accessible/tests/mochitest/tree/test_aria_globals.html

@@ -19,6 +19,7 @@
         "busy",
         "controls",
         "describedby",
+        "description",
         "disabled",
         "dropeffect",
         "flowto",
@@ -87,6 +88,7 @@
     <span id="busy" aria-busy="false"></span>
     <span id="controls" aria-controls="pawn"></span>
     <span id="describedby" aria-describedby="pawn"></span>
+    <span id="description" aria-description="hi"></span>
     <span id="disabled" aria-disabled="true"></span>
     <span id="dropeffect" aria-dropeffect="move"></span>
     <span id="flowto" aria-flowto="pawn"></span>
@@ -107,6 +109,7 @@
       <td id="td_busy" aria-busy="false"></td>
       <td id="td_controls" aria-controls="pawn"></td>
       <td id="td_describedby" aria-describedby="pawn"></td>
+      <td id="td_description" aria-description="hi"></td>
       <td id="td_disabled" aria-disabled="true"></td>
       <td id="td_dropeffect" aria-dropeffect="move"></td>
       <td id="td_flowto" aria-flowto="pawn"></td>