GitLab

This requires deleting WindowSelectorItem::RoundedContainerView.

screenshot: https://screenshot.googleplex.com/Gu5wG5LOPHY

Test: manual, run WindowSelectorTests
Bug: 839477
Change-Id: I933d0de5ba38a9c829d2266f945cc62fd2b5d7c9
Reviewed-on: https://chromium-review.googlesource.com/1161482
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580668}