WebUI: removing paper-slider

Bug: 902873
Change-Id: I2bfd69c997b5d0586eb07d0bfa120d4d0ddd80e8
Reviewed-on: https://chromium-review.googlesource.com/c/1389500
Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Reviewed-by: Dan Beam <dbeam@chromium.org>
Commit-Queue: Esmael El-Moslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618985}
17 files changed