This patch estimates the connection RTT using EventBasedExponentialMovingAverage. The half time is set to 500 but can be modified using field trials. This new metric is currently unused, but will be used for exploration of of whether it can be used instead of the existing metric. Bug: webrtc:11140 Change-Id: I9db93e9b9eb932e3cd18935cd4ce0d90fc1cb293 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/161000 Commit-Queue: Jonas Oreland <jonaso@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/master@{#29944}