Since the interval between the timestamps does not include the send/receive time of the last/first packet we correct the interval by adding the average of the interval between probing packets. BUG=webrtc:5859 R=mflodman@webrtc.org, stefan@webrtc.org Review URL: https://codereview.webrtc.org/2224173003 . Cr-Commit-Position: refs/heads/master@{#13719}