GitLab

This eases in and out the Omnibox popup opacity over 82ms as it opens
and closes. This matches the animation spec provided by UX.

Bug: 823535
Change-Id: Ic2add1f57f63ae6d043812f2bd5a766f84d302c9
Reviewed-on: https://chromium-review.googlesource.com/1081198
Commit-Queue: Tommy Li <tommycli@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Ali Juma <ajuma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#564295}