Which clients need this at the moment?

Policy for now; if a new policy is sent out that doesn't include some apps that were in the old policy, we need to uninstall those apps.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd

commit 3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd
Author: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Date: Thu Aug 30 14:29:30 2018

policy: Uninstall apps that are no longer forced installed

Implements the WebAppPolicyManager side of uninstalling policy-installed
apps.

WebAppPolicyManager saves a set of the apps it last installed. Then when
a new policy arrives, it compares the saved set with the most recent
set and uninstalls any apps that are not in the latest policy.

We keep this set of last installed apps because if we were to retrieve
the list of installed apps from the ExtensionIdsMap, we could miss some
uninstalls i.e. uninstalling apps that are in the process of being
installed. For example, if we get a new policy with apps A and B. While
we install A, a new policy arrives only with app A. If we were to
retrieve the list of installed apps, we would only see A and would miss
uninstalling B.

Bug:  876174 
Change-Id: I8805565ed8e38f2264a27a802b025bd8d4480cc2
Reviewed-on: https://chromium-review.googlesource.com/1195293
Commit-Queue: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587563}
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/bookmark_apps/BUILD.gn
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/bookmark_apps/policy/web_app_policy_manager.cc
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/bookmark_apps/policy/web_app_policy_manager.h
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/bookmark_apps/policy/web_app_policy_manager_unittest.cc
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/components/pending_app_manager.h
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/components/test_pending_app_manager.cc
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/components/test_pending_app_manager.h
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/extensions/pending_bookmark_app_manager.cc
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/extensions/pending_bookmark_app_manager.h
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/extensions/web_app_extension_ids_map.cc
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/extensions/web_app_extension_ids_map.h
[modify] https://crrev.com/3bd271c27e8d0f1f6712b79c0a79fdffc6a998dd/chrome/browser/web_applications/web_app_provider.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bfad279d02ae4976dcf962c534785fbcb0e95cdf

commit bfad279d02ae4976dcf962c534785fbcb0e95cdf
Author: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Date: Fri Aug 31 00:19:18 2018

desktop-pwas: Implement PendingAppManager::UninstallApps

UninstallApps adds uninstallation tasks to the queue of tasks and
uninstalls the corresponding extension for the provided URL.

Bug:  876174 
Change-Id: Id79adb12a0999332aaec830acb48eadbf62b2abb
Reviewed-on: https://chromium-review.googlesource.com/1196782
Commit-Queue: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587872}
[modify] https://crrev.com/bfad279d02ae4976dcf962c534785fbcb0e95cdf/chrome/browser/web_applications/extensions/pending_bookmark_app_manager.cc
[modify] https://crrev.com/bfad279d02ae4976dcf962c534785fbcb0e95cdf/chrome/browser/web_applications/extensions/pending_bookmark_app_manager_unittest.cc

Your change meets the bar and is auto-approved for M70. Please go ahead and merge the CL to branch 3538 manually. Please contact milestone owner if you have questions.
Owners: benmason@(Android), kariahda@(iOS), geohsu@(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/+/5fbf8d3ac6e98c9fe6bd37696fd3df8aeb31640c

commit 5fbf8d3ac6e98c9fe6bd37696fd3df8aeb31640c
Author: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Date: Wed Sep 05 00:41:39 2018

desktop-pwas: Implement PendingAppManager::UninstallApps

UninstallApps adds uninstallation tasks to the queue of tasks and
uninstalls the corresponding extension for the provided URL.

Bug:  876174 
Change-Id: Id79adb12a0999332aaec830acb48eadbf62b2abb
Reviewed-on: https://chromium-review.googlesource.com/1196782
Commit-Queue: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#587872}(cherry picked from commit bfad279d02ae4976dcf962c534785fbcb0e95cdf)
Reviewed-on: https://chromium-review.googlesource.com/1205970
Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Cr-Commit-Position: refs/branch-heads/3538@{#40}
Cr-Branched-From: 79f7c91a2b2a2932cd447fa6f865cb6662fa8fa6-refs/heads/master@{#587811}
[modify] https://crrev.com/5fbf8d3ac6e98c9fe6bd37696fd3df8aeb31640c/chrome/browser/web_applications/extensions/pending_bookmark_app_manager.cc
[modify] https://crrev.com/5fbf8d3ac6e98c9fe6bd37696fd3df8aeb31640c/chrome/browser/web_applications/extensions/pending_bookmark_app_manager_unittest.cc