+charleszhao, I wonder whether it is related to new ranker.

Hi Alex, Xiyuan, this bug exists even back to M69. 

I just add some log and find out the reason, which is:

(1) Chrome app still exists in the UpdateRecommendedResults:
https://cs.chromium.org/chromium/src/chrome/browser/ui/app_list/search/app_search_provider.cc?rcl=eca9fd593b12dc8111ac2d779ba42df78e872371&l=612

(2) Chrome app gets a very low score because the app->GetLastActivityTime() is null.

(3) This is true not only for chrome, here are some other apps have the last activity time as null all the time.

id: mgndgikekgjfcpckkfioiadnlibdjbkf/, title: Chromium
id: dhnmfjegnohoakobpikffnelcemaplkm, title: Settings
id: iniodglblcgmngkgdipeiclkdjjpnlbn, title: Camera

Somehow the last activity time is not set for those type of apps?

Thanks Charles to dig into it.

"Settings" is an internal app and I don't think we track the launch time for them. +wutao@ has a bug to track that (somehow I am unable to find it).

"Chrome" is a special app that we shortcut its launch. Looks like it has a side effect of causing its launch time not recorded.

Not sure about "Camera", I saw a CL to migrate it to use the Android one. Maybe that transition caused the activity time to lost. But after you launch it once, it should recover from the state.

Hi xiyuan@, we may only mention to add launch time to "Settings" in some design doc.

Just checked on M69 which where suggested apps look differently, but behavior is the same: Chrome is there initially, but gets pushed out and never show up again. So at least this is not a regression. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c1835110652edd4411000a6cadb3bb580449c410

commit c1835110652edd4411000a6cadb3bb580449c410
Author: Vladislav Kaznacheev <kaznacheev@google.com>
Date: Sat Dec 01 00:16:55 2018

Record launch time for Chrome app

Without this Chrome is pushed out of the list of suggested apps
very soon after the profile creation and never comes back even
after it is launched.

Bug:  894898 
Test: manual
Change-Id: I7d12958c1522336bf831d31b9288a6084cc5f974
Reviewed-on: https://chromium-review.googlesource.com/c/1338472
Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612868}
[modify] https://crrev.com/c1835110652edd4411000a6cadb3bb580449c410/chrome/browser/ui/app_list/app_list_client_impl_browsertest.cc
[modify] https://crrev.com/c1835110652edd4411000a6cadb3bb580449c410/chrome/browser/ui/ash/launcher/browser_shortcut_launcher_item_controller.cc
[modify] https://crrev.com/c1835110652edd4411000a6cadb3bb580449c410/chrome/browser/ui/ash/launcher/browser_shortcut_launcher_item_controller.h
[modify] https://crrev.com/c1835110652edd4411000a6cadb3bb580449c410/chrome/browser/ui/ash/launcher/chrome_launcher_controller_browsertest.cc
[modify] https://crrev.com/c1835110652edd4411000a6cadb3bb580449c410/chrome/browser/ui/ash/launcher/extension_launcher_context_menu.cc

Bulk moving <p-1's to the next milestone because we branched to M-73.

(didn't mean to grab these P-1's)

Verified in 73.0.3629.0

Your change meets the bar and is auto-approved for M72. Please go ahead and merge the CL to branch 3626 manually. Please contact milestone owner if you have questions.
Owners: govind@(Android), kariahda@(iOS), djmm@(ChromeOS), abdulsyed@(Desktop)

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

This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

Thanks for your time! To disable nags, add the Disable-Nags label.

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/+/c9acb33e6de3d402666fc2f493fce9dc880ed649

commit c9acb33e6de3d402666fc2f493fce9dc880ed649
Author: Vladislav Kaznacheev <kaznacheev@google.com>
Date: Mon Dec 10 19:53:09 2018

Record launch time for Chrome app

Without this Chrome is pushed out of the list of suggested apps
very soon after the profile creation and never comes back even
after it is launched.

Bug:  894898 
Test: manual
Change-Id: I7d12958c1522336bf831d31b9288a6084cc5f974
Reviewed-on: https://chromium-review.googlesource.com/c/1338472
Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#612868}(cherry picked from commit c1835110652edd4411000a6cadb3bb580449c410)
Reviewed-on: https://chromium-review.googlesource.com/c/1370400
Reviewed-by: Vladislav Kaznacheev <kaznacheev@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#229}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}
[modify] https://crrev.com/c9acb33e6de3d402666fc2f493fce9dc880ed649/chrome/browser/ui/app_list/app_list_client_impl_browsertest.cc
[modify] https://crrev.com/c9acb33e6de3d402666fc2f493fce9dc880ed649/chrome/browser/ui/ash/launcher/browser_shortcut_launcher_item_controller.cc
[modify] https://crrev.com/c9acb33e6de3d402666fc2f493fce9dc880ed649/chrome/browser/ui/ash/launcher/browser_shortcut_launcher_item_controller.h
[modify] https://crrev.com/c9acb33e6de3d402666fc2f493fce9dc880ed649/chrome/browser/ui/ash/launcher/chrome_launcher_controller_browsertest.cc
[modify] https://crrev.com/c9acb33e6de3d402666fc2f493fce9dc880ed649/chrome/browser/ui/ash/launcher/extension_launcher_context_menu.cc

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/c9acb33e6de3d402666fc2f493fce9dc880ed649

Commit: c9acb33e6de3d402666fc2f493fce9dc880ed649
Author: kaznacheev@google.com
Commiter: kaznacheev@chromium.org
Date: 2018-12-10 19:53:09 +0000 UTC

Record launch time for Chrome app

Without this Chrome is pushed out of the list of suggested apps
very soon after the profile creation and never comes back even
after it is launched.

Bug:  894898 
Test: manual
Change-Id: I7d12958c1522336bf831d31b9288a6084cc5f974
Reviewed-on: https://chromium-review.googlesource.com/c/1338472
Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#612868}(cherry picked from commit c1835110652edd4411000a6cadb3bb580449c410)
Reviewed-on: https://chromium-review.googlesource.com/c/1370400
Reviewed-by: Vladislav Kaznacheev <kaznacheev@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#229}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}