CL here: https://chromium-review.googlesource.com/c/chromium/src/+/1340315

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/dbbbfb3c2522ddd5d7e1236130b85bcf10f4816f

commit dbbbfb3c2522ddd5d7e1236130b85bcf10f4816f
Author: Mario Sanchez Prada <mario@igalia.com>
Date: Tue Nov 27 08:25:08 2018

Migrate TokenHandleFetcher to the IdentityManager

Move away from OAuth2TokenService and SigninManagerBase by implementing
IdentityManager::Observer and using Identity Service's APIs only (i.e.
IdentityManager, PrimaryAccessTokenFetcher).

Bug:  905689 
Change-Id: I68e971ddf8a23987abfdadb8e2daf7b17a4a6ddb
Reviewed-on: https://chromium-review.googlesource.com/c/1340315
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Cr-Commit-Position: refs/heads/master@{#611044}
[modify] https://crrev.com/dbbbfb3c2522ddd5d7e1236130b85bcf10f4816f/chrome/browser/chromeos/login/signin/token_handle_fetcher.cc
[modify] https://crrev.com/dbbbfb3c2522ddd5d7e1236130b85bcf10f4816f/chrome/browser/chromeos/login/signin/token_handle_fetcher.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c352b1d635eeb4b19c2326620a63e1fde5d189c7

commit c352b1d635eeb4b19c2326620a63e1fde5d189c7
Author: Mario Sanchez Prada <mario@igalia.com>
Date: Tue Nov 27 12:42:36 2018

Simplify token retrieval logic in TokenHandleFetcher

Instead of relying on an implementation of IdentityManager::Observer and
a private flag to know when a RefreshToken is available before requesting
using PrimaryAccountAccessTokenFetcher, use PAATF's mode to wait until the
primary account has a refresh token available (i.e. kWaitUntilAvailable)
whenever needed when TokenHandleFetcher::BackfillToken() is invoked, or
simply using kImmediate if such refresh token is already available.

Bug:  905689 
Change-Id: Idf8e8b58a9bda518f2bd11d140b4e8776194a8f4
Reviewed-on: https://chromium-review.googlesource.com/c/1343264
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611079}
[modify] https://crrev.com/c352b1d635eeb4b19c2326620a63e1fde5d189c7/chrome/browser/chromeos/login/signin/token_handle_fetcher.cc
[modify] https://crrev.com/c352b1d635eeb4b19c2326620a63e1fde5d189c7/chrome/browser/chromeos/login/signin/token_handle_fetcher.h