Please let me file a new bug rather than re-using bug 107797. There are still cases where a Touch event is not fired in shadow tree. I'll attach a testcase later.
Created attachment 186548 [details] Event listeners on nodes in shadow tree are not fired. Put it on LayoutTests/fast/dom/shadow/
https://bugs.webkit.org/show_bug.cgi?id=107800 fixed also this.
The subject of this bug should use 'Touch Event' rather than 'Gesture event'.