[Selection API] Add DOM Mutations removal test
Add a tentative WPT test where we remove various DOM nodes and see its
effect on the getComposedRanges' returned StaticRanges.
Change-Id: I3d9c22b499a5a3fc4905dce2a46fa9ddaef85f45
Bug: 40286116
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5938337
Reviewed-by: Siye Liu siliu@microsoft.com
Commit-Queue: Di Zhang dizhangg@chromium.org
Cr-Commit-Position: refs/heads/main@{#1370101}