Bug 1696309 - Don't skip aria-owned children early in TreeWalker. r=Jamie

This causes problems when the aria-owns is invalid, for example in a
cyclical link. The reason this was put in in the first place is not
documented or apparent, but maybe a way to reduce churn.

This also fixes an existing test and makes the lineage of a cyclical
aria-owns elements match what chrome does.
(t3_1, t3_2, heading, t3_3).

Differential Revision: https://phabricator.services.mozilla.com/D221276

accessible/base/TreeWalker.cpp

@@ -324,17 +324,7 @@ LocalAccessible* TreeWalker::AccessibleFor(nsIContent* aNode, uint32_t aFlags,
 
   // Create an accessible if allowed.
   if (!(aFlags & eWalkCache) && mContext->IsAcceptableChild(aNode)) {
-    // We may have ARIA owned element in the dependent attributes map, but the
-    // element may be not allowed for this ARIA owns relation, if the relation
-    // crosses out XBL anonymous content boundaries. In this case we won't
-    // create an accessible object for it, when aria-owns is processed, which
-    // may make the element subtree inaccessible. To avoid that let's create
-    // an accessible object now, and later, if allowed, move it in the tree,
-    // when aria-owns relation is processed.
-    if (mDoc->RelocateARIAOwnedIfNeeded(aNode) && !aNode->IsXULElement()) {
-      *aSkipSubtree = true;
-      return nullptr;
-    }
+    mDoc->RelocateARIAOwnedIfNeeded(aNode);
     return GetAccService()->CreateAccessible(aNode, mContext, aSkipSubtree);
   }
 

accessible/tests/mochitest/tree/test_aria_owns.html

@@ -43,16 +43,16 @@
       testAccessibleTree("t2_1", tree);
 
       tree =
-        { SECTION: [ // t3_3
-          { GROUPING: [ // t3_1
-            { NOTE: [ // t3_2
-              { HEADING: [ // DOM child of t3_2
+        { GROUPING: [ // t3_1
+          { NOTE: [ // t3_2
+            { HEADING: [ // DOM child of t3_2
+              { SECTION: [ // t3_3
                 // no kids, no loop
               ] },
             ] },
           ] },
         ] };
-      testAccessibleTree("t3_3", tree);
+      testAccessibleTree("t3_1", tree);
 
       tree =
         { SECTION: [ // t4_1
@@ -122,6 +122,17 @@
         ] };
       testAccessibleTree("presentation_owner", tree);
 
+      tree =
+        { GROUPING: [ // t7
+          { SECTION: [ // t7_1
+            { SECTION: [ // t7_2
+              { SECTION: [ { TEXT_LEAF: [] } ] },
+              ] },
+            ] },
+            { role: ROLE_PUSHBUTTON, name: "heck yes" },
+        ] };
+      testAccessibleTree("t7", tree);
+
       SimpleTest.finish();
     }
 
@@ -192,6 +203,15 @@
   <div id="presentation" role="presentation">
     <div id="presentation_owner" aria-owns="presentation"></div>
   </div>
+
+  <div id="t7" role="group">
+    <div id="t7_1" role="presentation">
+      <div id="t7_2" role="presentation">
+          <div aria-owns="t7_2">heck yes</div>
+      </div>
+    </div>
+    <div role="button" aria-labelledby="t7_1"></div>
+  </div>
 </body>
 
 </html>