Time triggered tasks in the SendSideCongestionController caused
flakyness in long running unit tests of SendSideCongestionController.
This CL lets the unit test code disable the periodic tasks so they are
only triggered on demand.
Bug: webrtc:9039
Change-Id: I934045d7e6eeaa765dd221cef87389f1d98b58a5
Reviewed-on: https://webrtc-review.googlesource.com/63265
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22536}
247e0b4713