SequencedTaskChecker is not part of rtc_base_approved and will not work
in Chromium. This CL simply removes it since it was just a precaution
and is not necessary for the tool. The thread assumptions are stated in
the class comment.
TBR=phensman@webrtc.org
Bug: webrtc:9642
Change-Id: I871ac361975595d8ed07b2e2447e3581c9ba9968
Reviewed-on: https://webrtc-review.googlesource.com/95648
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24401}
1b5e5db842