Fix bug in calculation of averge queue time in paced sender.

Also work around a flaw in fake encoder which caused bogus perf
regression in rampup tests.

BUG=560434
R=mflodman@webrtc.org, stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1474533006 .

Cr-Original-Commit-Position: refs/heads/master@{#10811}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: ad113e50d251c95adcf501ed29f8312ad1193a35
4 files changed