Issue 890768  has been merged into this issue.

This will also benefit from the new AccountsMutator APIs to migrate away from AccountTrackerService::SeedAccountInfo().

Starting to work on this with starting to remove Signin Manager, first.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/eb3eb9163a613230a85ec6356eb6abbb6ed4472f

commit eb3eb9163a613230a85ec6356eb6abbb6ed4472f
Author: Julie Jeongeun Kim <jkim@igalia.com>
Date: Wed Jan 16 05:49:29 2019

[s13n] Convert CWVSyncController to IdentityManager

This CL only migrates CWVSyncController production code away from
SigninManager, leaves migration away from ProfileOAuth2TokenService
and AccountTrackerService for a follow up step.

Bug: 903838
Change-Id: Ifc8e1f471554af3211bd020112265d57c9360e72
Reviewed-on: https://chromium-review.googlesource.com/c/1404543
Reviewed-by: Hiroshi Ichikawa <ichikawa@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Julie Jeongeun Kim <jkim@igalia.com>
Cr-Commit-Position: refs/heads/master@{#623126}
[modify] https://crrev.com/eb3eb9163a613230a85ec6356eb6abbb6ed4472f/ios/web_view/internal/cwv_web_view_configuration.mm
[modify] https://crrev.com/eb3eb9163a613230a85ec6356eb6abbb6ed4472f/ios/web_view/internal/sync/cwv_sync_controller.mm
[modify] https://crrev.com/eb3eb9163a613230a85ec6356eb6abbb6ed4472f/ios/web_view/internal/sync/cwv_sync_controller_internal.h
[modify] https://crrev.com/eb3eb9163a613230a85ec6356eb6abbb6ed4472f/ios/web_view/internal/sync/cwv_sync_controller_unittest.mm

For removing ATS, the new issue was created. crbug.com/922801.
So, I'll handle removing ATS with crbug.com/922801 and close this issue.

Hi Julie, this bug can still be open for eliminating the usage of ProfileOAuth2TokenService, right? Thanks!

Hi Colin,
Right. I'll add 'Blocked on' issue with crbug.com/913927.