Bug 1355423 - Fix AtkRole and AXSubrole for ARIA treeitem. r=surkov

accessible/base/RoleMap.h

@@ -306,8 +306,8 @@ ROLE(OUTLINE,
 
 ROLE(OUTLINEITEM,
      "outlineitem",
-     ATK_ROLE_LIST_ITEM,
-     NSAccessibilityRowRole,  //XXX: use OutlineRow as subrole.
+     ATK_ROLE_TREE_ITEM,
+     NSAccessibilityRowRole,
      ROLE_SYSTEM_OUTLINEITEM,
      ROLE_SYSTEM_OUTLINEITEM,
      eNameFromSubtreeRule)

accessible/mac/mozAccessible.mm

@@ -901,6 +901,9 @@ ConvertToNSArray(nsTArray<ProxyAccessible*>& aArray)
     case roles::NOTE:
       return @"AXDocumentNote";
 
+    case roles::OUTLINEITEM:
+      return @"AXOutlineRow";
+
     // macOS added an AXSubrole value to distinguish generic AXGroup objects
     // from those which are AXGroups as a result of an explicit ARIA role,
     // such as the non-landmark, non-listitem text containers in DPub ARIA.