b9d8d10d42
StunRequestTests were using the real time clock to measure fairly large retransmit intervals (up to several seconds). This was making the tests slow and flaky when the system was heavily loaded. See https://build.chromium.org/p/client.webrtc/builders/Win64%20Release/builds/9274/steps/rtc_unittests/logs/stdio for an example of a recent failure. This change makes the tests use a simulated clock instead. They are now very quick, precise and reliable. R=honghaiz@webrtc.org, zhihuang@webrtc.org Review URL: https://codereview.webrtc.org/2300143005 . Cr-Commit-Position: refs/heads/master@{#14097}