Reland RedirectNonUINonIOBrowserThreads to TaskScheduler by default on trunk

This reverts commit f07732ec0e39ad7e9f1ad279f2624dbdf261803d
(https://codereview.chromium.org/2791933004)
and reapplies b6d0c9a06ab573af760763fcd7ecf76ae2c87695
(https://codereview.chromium.org/2690183002/).

BUG=653916, 707986
TBR=jam@chromium.org, rkaplow@chromium.org
Previously reviewed at https://codereview.chromium.org/2690183002/

Review-Url: https://codereview.chromium.org/2856583002
Cr-Commit-Position: refs/heads/master@{#468376}


CrOS-Libchrome-Original-Commit: 3e27cb6e501ae55d614b56d566487590518ec223
1 file changed
tree: 49bc7fe93f3484b2be9fd6eda6d3933f1eb7140d
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/