GitLab

- Delete powerwash dialog from browser settings
- Remove settings animated pages, main page behavior, and route
  observer behavior from browser about page

Bug: 990170
Change-Id: I1f2f0a1eb454d55c8f84b7374c7be4e66b238ea2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1979082
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727019}