Ensure XMLDocumentParser doesn't hit a nullptr isolate while parsing a fragment
Bug: 376320342
Change-Id: I32e153fd991088bf3a85c9977fcb0c4506713491
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5984010
Reviewed-by: Joey Arhar jarhar@chromium.org
Auto-Submit: Nate Chapin japhet@chromium.org
Commit-Queue: Nate Chapin japhet@chromium.org
Cr-Commit-Position: refs/heads/main@{#1377775}