coral: Add slide in/out animation to selector view

Uses a clip and translation to slide the selector view in and out. The
clip is necessary as the selector view is normally larger than the coral
chip.

To ensure the selector view is stacked beneath the coral chip, we have
to parent it to a different container.

Bug: 376120706
Test: manual
Change-Id: Ib31a636dfa88acb13b73ade3236f3afa723b65e0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5973664
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiaodan Zhu <zxdan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1375608}