CandidateStats didn't use an initializer list which caused the `candidate` member variable to be constructed with a random id (calling an expensive rng method), only to be overwritten directly thereafter. Bug: webrtc:12840 Change-Id: I0366f674281d236896cb9539812dc2d88c1b37ef Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/221600 Reviewed-by: Henrik Boström <hbos@webrtc.org> Commit-Queue: Tommi <tommi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34244}