Add XR instrumentation web content workaround

Adds a workaround for https://crbug.com/908917 into the XR
instrumentation test setup since attempts to work around the issue in
the test runner haven't been completely successful. This workaround
performs a swipe which should be a no-op when running a RenderTest,
which seems to prevent the flakiness when doing pixel diffs.

Bug: 908917
Change-Id: I38bf8fb5abe1c0a2bf19e044dd9237919ec2b019
Reviewed-on: https://chromium-review.googlesource.com/c/1362293
Reviewed-by: Bill Orr <billorr@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614250}
5 files changed