There is a pattern that is safe to convert however, this is when iterating over accounts returned by PO2TS, e.g. like done in signed_in_accounts_view_controller.mm.

  for (const std::string& account_id : oauth2_service->GetAccounts()) {
    AccountInfo account = accountTracker->GetAccountInfo(account_id);
    ...
  }

This can be replaced by the following:

  for (const AccountInfo account_info :
      identity_service->GetAccountsWithRefreshToken()) {
    ...
  }

Given https://bugs.chromium.org/p/chromium/issues/detail?id=908840#c3, we can convert AccountTrackerService::GetAccountInfo() to IdentityManager::GetAccountInfoForAccountWithRefreshToken().

The exceptions are 1. internal uses in components/signin, 2. use from PO2TS delegate implementations.

Sample CL: https://chromium-review.googlesource.com/c/chromium/src/+/1354447

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