GitLab

This CL enables dynamic UiDevTools creation and adds "Create Ui
Dev Tools" button to Ash HUD.

Bug: 1138734

Change-Id: I4458f355241ce6c4c43494f9ee14956f0253b30f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2535010Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Wei Li <weili@chromium.org>
Commit-Queue: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845059}