The fix is to make app_list_controller_impl observe wallpaper_controller in the same way with https://cs.chromium.org/chromium/src/ash/app_list/app_list_controller_impl.cc?sq=package:chromium&l=409
See unittest here for example: https://cs.chromium.org/chromium/src/ash/app_list/app_list_presenter_delegate_unittest.cc?q=app_list_presenter_delegate_unit&sq=package:chromium&dr&l=1191
The following revision refers to this bug: https://chromium.googlesource.com/chromium/src.git/+/ecaac45637f87b237c105395e2f2d46f927a9e6a commit ecaac45637f87b237c105395e2f2d46f927a9e6a Author: Wenzhao Zang <wzang@chromium.org> Date: Wed May 16 23:27:05 2018 cros: Hide home launcher during wallpaper preview Bug: 834993 Test: --enable-features=EnableHomeLauncher, --new-wallpaper-picker Change-Id: I499db4f6bbb5511f5feb6da0b5df5ccd7ef1143f Reviewed-on: https://chromium-review.googlesource.com/1058490 Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org> Reviewed-by: Xiyuan Xia <xiyuan@chromium.org> Cr-Commit-Position: refs/heads/master@{#559331} [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/app_list/app_list_controller_impl.cc [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/app_list/app_list_controller_impl.h [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/app_list/app_list_presenter_delegate_unittest.cc [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/wallpaper/wallpaper_controller.cc [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/wallpaper/wallpaper_controller.h [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/wallpaper/wallpaper_controller_observer.h [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/wallpaper/wallpaper_controller_test_api.cc [modify] https://crrev.com/ecaac45637f87b237c105395e2f2d46f927a9e6a/ash/wallpaper/wallpaper_controller_test_api.h
Comment 1 by weidongg@chromium.org
, Apr 19 2018