The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4620e6d60f26c40b3707c29279e083a86629fc5e

commit 4620e6d60f26c40b3707c29279e083a86629fc5e
Author: wutao <wutao@chromium.org>
Date: Thu Mar 15 17:25:29 2018

cros: Add UMA to measure latency to show/hide Launcher UI.

This cl adds UMA to measure input latency to show/hide launcher UI.

Bug:  821184 
Test: tested on eve with added UMA.
Change-Id: I8c87684371d92e8da0a7e7e8731932f5fd61d4d1
Reviewed-on: https://chromium-review.googlesource.com/961253
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543422}
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/accelerators/accelerator_controller.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/app_list_controller_impl.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/app_list_controller_impl.h
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/app_list_presenter_delegate.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/app_list_presenter_impl.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/app_list_presenter_impl.h
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/app_list_view_delegate_mash.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/presenter/app_list_presenter_impl_unittest.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/app_list/test/app_list_test_helper.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/shelf/app_list_shelf_item_delegate.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ash/shelf/shelf_layout_manager.cc
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/tools/metrics/histograms/histograms.xml
[modify] https://crrev.com/4620e6d60f26c40b3707c29279e083a86629fc5e/ui/app_list/app_list_metrics.h