GitLab

Concurrency checks gives bogus worker_count values
since https://chromium-review.googlesource.com/c/chromium/src/+/2304972
The thread that just returned from worker task will still count as
active. This can cause races that will trigger dcheck. This could be
fixed probably by tweaking worker_count similar to
https://chromium-review.googlesource.com/c/chromium/src/+/2355297
Since this is dcheck-only code that adds significant complexity however,
it makes more sense to strip the code:
- dcheck can trigger in valid use cases
- The issues that the dcheck will catch would also cause Join to never
  return. This should be easy enough to detect without the dcheck.

Bug: 1114823
Change-Id: I1181ba7f530cf81624f578ed0f324849ad930e41
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2363074
Commit-Queue: François Doray <fdoray@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799301}