GitLab

When Alt-tab ends, leading to a desk switch, we should query
the traget active desk, not the currently active desk, since
the desk switch animation will be in progress.

BUG=1042486
TEST=Added new tests

Change-Id: I17481169bf9cd1b9a66bec702a9fafafeac6cc85
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2004059
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732704}