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As requested by UX team, disable the ink drop effect of the scrollable
shelf's arrow button by this CL.

Bug: 1019012
Change-Id: I6a7224911cafb70167d4f152b53b93fdd3fa6004
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1885500
Auto-Submit: Andrew Xu <andrewxu@chromium.org>
Commit-Queue: Manu Cornet <manucornet@chromium.org>
Reviewed-by: Manu Cornet <manucornet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710339}