Migrate WaitableEvent to enum-based constructor in services/

services/shell/standalone/tracer.cc

Index: services/shell/standalone/tracer.cc
diff --git a/services/shell/standalone/tracer.cc b/services/shell/standalone/tracer.cc
index cffcfe09c552472a3512781d1ecf6169c6b9d8e1..2edf844e95bd8d3afeea46cb544533f9e6db2f33 100644
--- a/services/shell/standalone/tracer.cc
+++ b/services/shell/standalone/tracer.cc
@@ -86,7 +86,9 @@ void Tracer::StopTracingAndFlushToDisk() {
     // gather as much data as possible on shutdown.
     base::trace_event::TraceLog::GetInstance()->SetDisabled();
     {
-      base::WaitableEvent flush_complete_event(false, false);
+      base::WaitableEvent flush_complete_event(
+          base::WaitableEvent::ResetPolicy::AUTOMATIC,
+          base::WaitableEvent::InitialState::NOT_SIGNALED);
       // TraceLog::Flush requires a message loop but we've already shut ours
       // down.
       // Spin up a new thread to flush things out.