Async Clipboard: Automate/duplicate WPT tests

- Having WPT tests run on buildbots automatically should increase velocity
(no longer need to run them manually and reduce chance of regressions
- Note to update corresponding tests so that buildbots and web platform are both
up to date.

Bug: 896479
Change-Id: Ic2dcbe46fac51dcd1ef01af7f5ed0f360a3ee00f
Reviewed-on: https://chromium-review.googlesource.com/c/1404401
Reviewed-by: Gary Kacmarcik <garykac@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Commit-Queue: Darwin Huang <huangdarwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622275}
15 files changed