MessageLoop: wire the unused static method in base::Thread (follow-up cleanup)

Actually use the private static method (CreateUnbound) in base::Thread.

I added the method in the last refactoring patch but forgot to use it;
I can either remove the static method or use it, I do the latter in this
patch as I thought leaving the private ctor of MessageLoop only for
delegated use-case cleaner.

BUG=465458
R=thakis@chromium.org

Review URL: https://codereview.chromium.org/1212193003

Cr-Commit-Position: refs/heads/master@{#336710}


CrOS-Libchrome-Original-Commit: 547a48bb006e275f1192c983a634e911c8c1edbd
2 files changed
tree: fd499f6e3ea35752dd0ffb3b98c83900f7ef8f1c
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/