In addition, timestamps are now absolute instead of relative to LOG_START. BUG=webrtc:4741 R=henrik.lundin@webrtc.org, kwiberg@webrtc.org, stefan@webrtc.org, terelius@webrtc.org Review URL: https://codereview.webrtc.org/1209563002. Cr-Commit-Position: refs/heads/master@{#9509}