node->shadowAncestorNode() returns node itself if node is not in ShadowDOM. This might be sometimes useful, however it is very confusing sometimes. It should return null if it is not in Shadow DOM, or we should have another non-confusing method.
+1
*** Bug 87230 has been marked as a duplicate of this bug. ***
Now it seems this is equivalent to Bug 91821 *** This bug has been marked as a duplicate of bug 91821 ***