Revert "Add a trace event when a task scheduler worker is active."

This reverts commit d641a6adecc1dddf67823f2b424b6ebac79bce02.

Reason for revert: This CL causes TSan failures: crbug.com/811482

Original change's description:
> Add a trace event when a task scheduler worker is active.
> 
> Example trace with this enabled: https://drive.google.com/file/d/11si1qvQUhRi1jMPNTzgJpqp3D-yFKOf7/view?usp=sharing
> 
> Also fix a racy setup order in MemoryDumpManagerTest exercised by this change.
> 
> R=​fdoray@chromium.org
> 
> Bug: 811035
> Change-Id: I328dca43f7b5bfd42bcf1a69b1e191fe41523ade
> Reviewed-on: https://chromium-review.googlesource.com/913251
> Reviewed-by: François Doray <fdoray@chromium.org>
> Commit-Queue: Gabriel Charette <gab@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#536177}

TBR=gab@chromium.org,primiano@chromium.org,fdoray@chromium.org

Change-Id: I6372620c5cff7b04d44be9909f3123436ee6019c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 811035
Reviewed-on: https://chromium-review.googlesource.com/915581
Reviewed-by: Hajime Hoshi <hajimehoshi@chromium.org>
Commit-Queue: Hajime Hoshi <hajimehoshi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536256}

CrOS-Libchrome-Original-Commit: afeefc5f0138cda1aa5f1f87e67876dbebcdf7f2
2 files changed
tree: a9323abf7171d23648c50832c3ae387878123727
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/