I've just started to look into this one so maybe it's a silly question, but grepping around I found other delegates:

  * extensions/shell/browser/shell_oauth2_token_service_delegate.h
  * google_apis/gaia/fake_oauth2_token_service_delegate.h

Any comment on what should be done for those two?

Hi Mario,

Not a silly question at all! We don't need to do anything for those delegates at this time, as they're not delegates of ProfileOAuth2TokenService. There is a ChromeOS delegate in //chrome that we'll need to handle; I'm going to make a bug for that one but need to finish examining it first. Thanks!

Sounds good, thanks for clarifying. Also, sorry for posting on the wrong ticket, my comment should have been placed in crbug.com/912137, posted it here by mistake (was reading the 2 tickets at the same time)

Quick heads-up, see the CLs for the 2 steps mentioned here below:
  * Cleanup of dependencies in MutableProfileOAuth2TokenServiceDelegate: https://chromium-review.googlesource.com/c/chromium/src/+/1424880
  * Move MutableProfileOAuth2TokenServiceDelegate into //components: https://chromium-review.googlesource.com/c/chromium/src/+/1425500

I'll move then into review as soon as bots are green

One more comment:

As mentioned by @msarda in the review for the first CL (1424880), "passing this thought the client has the downside that we have implement it on iOS where it is actually never used. Let's pass the NetworkConectionTracker as an extra parameter in the constructor of the MutableProfileOAuth2TokenServiceDelegate and remove it from the SigninClient."

So, the first CL has changed into implementing that strategy.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/efedc0a38f94579295b29d0fccf0e035ef109e01

commit efedc0a38f94579295b29d0fccf0e035ef109e01
Author: Mario Sanchez Prada <mario@igalia.com>
Date: Tue Jan 22 14:26:02 2019

Don't depend on //content from MutableProfileOAuth2TokenServiceDelegate

Remove the dependency from the production file by having a reference to
the NetworkConnectionTracker in MutableProfileOAuth2TokenServiceDelegate,
and from the associated unit test by relying on ScopedTaskEnvironment.

Bug: 922555
Change-Id: I7e5885cb41007ec5ee72f562b9cca48f307338f0
Reviewed-on: https://chromium-review.googlesource.com/c/1424880
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624772}
[modify] https://crrev.com/efedc0a38f94579295b29d0fccf0e035ef109e01/chrome/browser/signin/mutable_profile_oauth2_token_service_delegate.cc
[modify] https://crrev.com/efedc0a38f94579295b29d0fccf0e035ef109e01/chrome/browser/signin/mutable_profile_oauth2_token_service_delegate.h
[modify] https://crrev.com/efedc0a38f94579295b29d0fccf0e035ef109e01/chrome/browser/signin/mutable_profile_oauth2_token_service_delegate_unittest.cc
[modify] https://crrev.com/efedc0a38f94579295b29d0fccf0e035ef109e01/chrome/browser/signin/profile_oauth2_token_service_factory.cc