add port and tag for chrome

Plan is that we will also use test expectations and baselines at
Wptrunner side. Add a port for Chrome so that we can have chrome
specific baselines and test expectations, and the baselines and
test expectations will be used to regenerate wpt metadata.

Bug: 1481730, 1482887
Change-Id: I72f21b67f87d4800600ff8c9c724a3e3a9e426f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4968698
Commit-Queue: Weizhong Xia <weizhong@google.com>
Reviewed-by: Jonathan Lee <jonathanjlee@google.com>
Cr-Commit-Position: refs/heads/main@{#1215815}