A lot of code to call shadowAncestorNode don't consider nested shadow DOM. This exposes inner element of Shadow DOM. This meta bug trucks all of the shadowAncestorNode bugs.
I'm using the document to track the codes... https://docs.google.com/a/chromium.org/spreadsheet/ccc?key=0Aty2DXLelNGhdGZYSVljMVlKcUhQekpRbGdrTWRuWmc&pli=1#gid=0
Actually we still have lot of bugs around here. It's a shame.
Let me merge this bug and Bug 91589. These are both shadowAncestorNode()-related meta bug. *** This bug has been marked as a duplicate of bug 91589 ***
Mass move bugs into the DOM component.