Devtools: fix a failed aria assertion in ListControl.js

Issue:
Node.prototype.hasSameShadowRoot is used in ARIAUtils to check if two elements are in the same
shadow DOM since aria doesn't work well crossing shadow-boundaries
on occasion where node has not been added to the DOM yet by the time this API get called
(the associated bug is one of the instances), the assertion fails.

This change:
1. fix an issue exposed by the check in ListControl.js

Bug: 978634
Change-Id: Iefd8d3b50272f706b9a5e5310024abeb449ee230
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1680655
Commit-Queue: Junyi Xiao <juxiao@microsoft.com>
Reviewed-by: Erik Luo <luoe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681569}
1 file changed