[CrOS perf test] Rotation in Overview Mode

The reason why it was flaky was that it label animation was
going while rotating. Wait until label is shown so that
we rotate the screen including label.

I'll file a separae bug to cancel the label animation.

Bug: 952885
Change-Id: Ic2af278d44182ba87e3e934e58fe872d5bc3e83e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619423
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661381}
5 files changed