Add virtual/outofblink-cors[-ns]/external/wpt/xhr

Bug: 736308
Change-Id: If43151792576d37399bead99c863c225ff614056
Reviewed-on: https://chromium-review.googlesource.com/1151073
Reviewed-by: Adam Rice <ricea@chromium.org>
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578270}
4 files changed