Add scripts to support running WPT on Chromium CI.

testing/scripts/ is used to adapt swarming flags to WPT
flags (eg: for sharding), and also to kick-off the
cleanup step.

t_p/b/t/ is for converting
Chromium TestExpectations files into WPT Metadata files for skipped

t_p/b/t/ is run as a cleanup step on
each shard. It rewrites the output of a WPT run by inserting expected
statuses from the TestExpectations file, which includes supporting flaky
tests (ie: multiple expected statuses) which WPT doesn't currently

Bug: 937369
Change-Id: Ic7d2c037ec545f38a1101759db6eb04db54057c6
Commit-Queue: Luke Z <>
Reviewed-by: Dirk Pranke <>
Reviewed-by: Robert Ma <>
Cr-Commit-Position: refs/heads/master@{#672059}
7 files changed