Because thread_ object is created in Init, destructor used to crash when calling thread_->Stop() because it was referencing a null pointer. Bug: webrtc:9404 Change-Id: I1c943d0fa50f9341aaa516b32495bb25bf4d664b Reviewed-on: https://webrtc-review.googlesource.com/84122 Reviewed-by: Stefan Holmer <stefan@webrtc.org> Reviewed-by: Artem Titov <titovartem@webrtc.org> Commit-Queue: Sami Kalliomäki <sakal@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23682}