The two main sources of dependencies are:

chrome/common/mac/launchd.mm uses GTMSMJobCopyDictionary, GTMSMCopyJobCheckInDictionary, and GTMSMJobRemove (and chrome/browser/service_process/service_process_control_mac_unittest.mm uses them as well).

chrome/browser/ui/cocoa/l10n_util.mm uses GTMUILocalizerAndLayoutTweaker

There's also some uses in remoting but I'm not sure what they are about yet.

The first task is moving the GTM service management stuff (the GTMSM* functions) into //chrome somewhere.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2788395cc17f551a8619f91df1a4a42079a32ca8

commit 2788395cc17f551a8619f91df1a4a42079a32ca8
Author: Elly Fong-Jones <ellyjones@chromium.org>
Date: Mon Nov 26 17:02:28 2018

mac: drop dependencies on GTM service management, phase 1

This change drops uses of GTMSMJobRemove and GTMSMJobSubmit, and replaces themm
with uses of new functions in the mac::services namespace.

Bug: 903800
Change-Id: I0e38ddf3532274bd8ff0ea861f14707a183cd3ff
Reviewed-on: https://chromium-review.googlesource.com/c/1337823
Reviewed-by: Mark Mentovai <mark@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610864}
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/browser/service_process/service_process_control_mac.mm
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/browser/service_process/service_process_control_mac_unittest.mm
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/BUILD.gn
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/mac/launchd.h
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/mac/launchd.mm
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/mac/mock_launchd.h
[rename] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/mac/mock_launchd.mm
[add] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/mac/service_management.h
[add] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/mac/service_management.mm
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/service_process_util_mac.mm
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/common/service_process_util_posix.h
[modify] https://crrev.com/2788395cc17f551a8619f91df1a4a42079a32ca8/chrome/test/BUILD.gn

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f65d67a91521e77d08791e5ee5a512ffc49dc524

commit f65d67a91521e77d08791e5ee5a512ffc49dc524
Author: Elly Fong-Jones <ellyjones@chromium.org>
Date: Wed Jan 09 17:56:37 2019

mac cleanup: drop GTM service management dependencies

This change:

1) Adds mac::services::GetJobInfo and mac::services::CheckIn, which replace
   two GTM functions;
2) Changes Launchd and MockLaunchd to use these functions instead of the GTM
   ones;
3) Simplifies ServiceProcessControlMac somewhat as a result

This removes all remaining dependencies on the GTM service management code. The
next step in this work is to remove dependencies on GTMUILocalizer.

Bug: 903800
Change-Id: Ib6a4fe13cb8586a8ae0f6323ff5cafa4870ed636
Reviewed-on: https://chromium-review.googlesource.com/c/1396442
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621214}
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/browser/service_process/service_process_control_mac.mm
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/mac/launchd.h
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/mac/launchd.mm
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/mac/mock_launchd.h
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/mac/mock_launchd.mm
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/mac/service_management.h
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/mac/service_management.mm
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/service_process_util_mac.mm
[modify] https://crrev.com/f65d67a91521e77d08791e5ee5a512ffc49dc524/chrome/common/service_process_util_posix.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c2edcb9895d4923161e51225461d3baed4fe14a4

commit c2edcb9895d4923161e51225461d3baed4fe14a4
Author: Elly Fong-Jones <ellyjones@chromium.org>
Date: Thu Jan 10 16:46:42 2019

gtm: compile out service management code

It is no longer needed for Chrome builds.

Bug: 903800
Change-Id: I3dbe2fc9106f89e3ca1c147721cbe86c5cbd8563
Reviewed-on: https://chromium-review.googlesource.com/c/1404706
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621608}
[modify] https://crrev.com/c2edcb9895d4923161e51225461d3baed4fe14a4/third_party/google_toolbox_for_mac/BUILD.gn

Since we use the code, why not keep using it? We already only list the stuff we actually use in GTM's gn file and not all 65kLoCs. I'm not sure I understand the motivation here.