GitLab

This change adds a highlight element action which updates the css shadow of a
given element.

R=gogerald@chromium.org

Bug: 806868
Change-Id: Ife28259e4020721fd87487770b154c452425a48c
Reviewed-on: https://chromium-review.googlesource.com/c/1262555
Commit-Queue: Mathias Carlen <mcarlen@chromium.org>
Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597032}