Add default constructor for rtc::Event

Bug: webrtc:9962
Change-Id: Icaa91e657e6881fcb1553f354c07866109a0ea68
Reviewed-on: https://webrtc-review.googlesource.com/c/109500
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25535}
diff --git a/audio/audio_send_stream.cc b/audio/audio_send_stream.cc
index a357520..37f89c5 100644
--- a/audio/audio_send_stream.cc
+++ b/audio/audio_send_stream.cc
@@ -803,7 +803,7 @@
                                                bool has_packet_feedback) {
   RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
   RTC_DCHECK_GE(max_bitrate_bps, min_bitrate_bps);
-  rtc::Event thread_sync_event(false /* manual_reset */, false);
+  rtc::Event thread_sync_event;
   worker_queue_->PostTask([&] {
     // We may get a callback immediately as the observer is registered, so make
     // sure the bitrate limits in config_ are up-to-date.
@@ -823,7 +823,7 @@
 
 void AudioSendStream::RemoveBitrateObserver() {
   RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
-  rtc::Event thread_sync_event(false /* manual_reset */, false);
+  rtc::Event thread_sync_event;
   worker_queue_->PostTask([this, &thread_sync_event] {
     bitrate_allocator_->RemoveObserver(this);
     thread_sync_event.Set();