GitLab

This gives the fade in/out effect on the loading progress bar that 2D UI
now has.

BUG=853821
R=tiborg

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:linux_vr;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I3d07e2ea005c0fbaafb9042a257b3eac4979a4e9
Reviewed-on: https://chromium-review.googlesource.com/1104984
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568425}