Adds simulated time controller API.

Bug: webrtc:11255
Change-Id: I68289a45b9441b5e612433acd96dc3cb24e47ce4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/168122
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30443}
diff --git a/api/test/create_time_controller.h b/api/test/create_time_controller.h
index f4bd3f2..1b6896f 100644
--- a/api/test/create_time_controller.h
+++ b/api/test/create_time_controller.h
@@ -17,9 +17,13 @@
 
 namespace webrtc {
 
+// Creates a time coltroller that wraps |alarm|.
 std::unique_ptr<TimeController> CreateTimeController(
     ControlledAlarmClock* alarm);
 
+// Creates a time controller that runs in simulated time.
+std::unique_ptr<TimeController> CreateSimulatedTimeController();
+
 // This is creates a call factory that creates Call instances that are backed by
 // a time controller.
 std::unique_ptr<CallFactoryInterface> CreateTimeControllerBasedCallFactory(