The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2239ae835a7b7442b8602d9be9f1bfabff857b2c

commit 2239ae835a7b7442b8602d9be9f1bfabff857b2c
Author: wutao <wutao@chromium.org>
Date: Tue Mar 13 22:35:45 2018

cros: Add smoothness UMA for Launcher folder animations.

This cl adds UMA for Launcher folder show/hide animations.

Bug:  821160 
Test: Tested on eve and minnie with added UMA.
Change-Id: I8771df817445caa92900f66750ce4675c0150492
Reviewed-on: https://chromium-review.googlesource.com/959559
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542940}
[modify] https://crrev.com/2239ae835a7b7442b8602d9be9f1bfabff857b2c/tools/metrics/histograms/histograms.xml
[modify] https://crrev.com/2239ae835a7b7442b8602d9be9f1bfabff857b2c/ui/app_list/app_list_metrics.cc
[modify] https://crrev.com/2239ae835a7b7442b8602d9be9f1bfabff857b2c/ui/app_list/app_list_metrics.h
[modify] https://crrev.com/2239ae835a7b7442b8602d9be9f1bfabff857b2c/ui/app_list/views/app_list_folder_view.cc
[modify] https://crrev.com/2239ae835a7b7442b8602d9be9f1bfabff857b2c/ui/app_list/views/app_list_folder_view.h
[modify] https://crrev.com/2239ae835a7b7442b8602d9be9f1bfabff857b2c/ui/app_list/views/apps_grid_view.cc
[modify] https://crrev.com/2239ae835a7b7442b8602d9be9f1bfabff857b2c/ui/app_list/views/apps_grid_view.h

Requested to merge back to M66 in order to evaluate animation improvement.

Your change meets the bar and is auto-approved for M66. Please go ahead and merge the CL to branch 3359 manually. Please contact milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), josafat@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d4b51a2664f5786438f39421c8f64030a40dec3d

commit d4b51a2664f5786438f39421c8f64030a40dec3d
Author: wutao <wutao@chromium.org>
Date: Wed Mar 14 22:54:40 2018

M66 Merge: cros: Add smoothness UMA for Launcher folder animations.

This cl adds UMA for Launcher folder show/hide animations.

TBR=xiyuan@chromium.org,holte@chromium.org

Bug:  821160 
Test: Tested on eve and minnie with added UMA.
Change-Id: I8771df817445caa92900f66750ce4675c0150492
Reviewed-on: https://chromium-review.googlesource.com/959559
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#542940}(cherry picked from commit 2239ae835a7b7442b8602d9be9f1bfabff857b2c)
Reviewed-on: https://chromium-review.googlesource.com/963662
Reviewed-by: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/branch-heads/3359@{#251}
Cr-Branched-From: 66afc5e5d10127546cc4b98b9117aff588b5e66b-refs/heads/master@{#540276}
[modify] https://crrev.com/d4b51a2664f5786438f39421c8f64030a40dec3d/tools/metrics/histograms/histograms.xml
[modify] https://crrev.com/d4b51a2664f5786438f39421c8f64030a40dec3d/ui/app_list/app_list_metrics.cc
[modify] https://crrev.com/d4b51a2664f5786438f39421c8f64030a40dec3d/ui/app_list/app_list_metrics.h
[modify] https://crrev.com/d4b51a2664f5786438f39421c8f64030a40dec3d/ui/app_list/views/app_list_folder_view.cc
[modify] https://crrev.com/d4b51a2664f5786438f39421c8f64030a40dec3d/ui/app_list/views/app_list_folder_view.h
[modify] https://crrev.com/d4b51a2664f5786438f39421c8f64030a40dec3d/ui/app_list/views/apps_grid_view.cc
[modify] https://crrev.com/d4b51a2664f5786438f39421c8f64030a40dec3d/ui/app_list/views/apps_grid_view.h