Also change the type of "time interval" to int from uint32. Fixed a few TODO therein. I think we should have the following convention: 1. All time delay/intervals should have type int although the time instant should have time uint32_t. 2. "interval" is preferred to "delay" if the delay will be repeated (like rescheduling). BUG= R=pthatcher@webrtc.org Review URL: https://codereview.webrtc.org/1762863002 . Cr-Commit-Position: refs/heads/master@{#11888}