b3c6810be3
This will be useful for any tests that test objects with time-dependent behavior. It will allow such tests to be written in such a way that their outcome is more repeatable (less flaky), and will also allow such tests to finish quicker. For example, a test for STUN timeout doesn't need to wait the full timeout interval in real time; it can simply advance the simulated clock. BUG=webrtc:4925 R=pthatcher@webrtc.org Review URL: https://codereview.webrtc.org/1895933003 . Cr-Commit-Position: refs/heads/master@{#12950}