Send *Statistics and Timestamp messages from SimulatedMessageBridge

This makes the simulation environment much closer to reality.

Change-Id: Ie0f44c17d9c9a750363335def1b008cef8c809b0
diff --git a/aos/events/simulated_event_loop.cc b/aos/events/simulated_event_loop.cc
index c339ce0..b2e54bb 100644
--- a/aos/events/simulated_event_loop.cc
+++ b/aos/events/simulated_event_loop.cc
@@ -986,7 +986,13 @@
 }
 
 void SimulatedEventLoopFactory::DisableForwarding(const Channel *channel) {
+  CHECK(bridge_) << ": Can't disable forwarding without a message bridge.";
   bridge_->DisableForwarding(channel);
 }
 
+void SimulatedEventLoopFactory::DisableStatistics() {
+  CHECK(bridge_) << ": Can't disable statistics without a message bridge.";
+  bridge_->DisableStatistics();
+}
+
 }  // namespace aos