GitLab

back_gesture: Update overscroll visuals.

See the recorded video:
https://drive.google.com/file/d/0B5I0jFeLxqIiRldva1VIaVJPNWRrUXlfUmtXOV9zdEFmVDZR/view?usp=sharing

Bug: 1016547
Change-Id: Ifb8c85dbda12b1fa7088d37beda6b8279b8ea6e3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1881811Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Min Chen <minch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711866}