1839577 - Add a complementary function for OkIf

Status: NEW

(Core :: Storage: Quota Manager, task, P3)

Description

[Jan Varga [:janv]]

Bug 1839551 is mapping OkIf result instead of returning a custom return value:

  QM_TRY(OkIf(!QuotaManager::IsShuttingDown()).mapErr([](const auto&) {
    return NS_ERROR_ABORT;
  }));

I think the code would be even nicer if we had a function like ErrIf<ErrorValue>:

  QM_TRY(ErrIf<NS_ERROR_ABORT>(QuotaManager::IsShuttingDown()));