Add browser test for issue 947683

It was reported that pressing right arrow with search button
would focus on the last shelf item when ChromeVox enabled. On
Tot, this issue has been fixed. Write a browser test to avoid
regression.

Test: browser_tests
Bug: 947683
Change-Id: Icdd250101b14c7d7175167801fb5478915845d1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1580222
Commit-Queue: Andrew Xu <andrewxu@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654231}
3 files changed