Fix a crash in the event tracing shutdown path

webrtc/base/event_tracer.cc

Index: webrtc/base/event_tracer.cc
diff --git a/webrtc/base/event_tracer.cc b/webrtc/base/event_tracer.cc
index 57c28fcbdc37ff92a0b891ff0af9d0cf460e37a5..8802095680092581982c51c43553fbfe6d1b220c 100644
--- a/webrtc/base/event_tracer.cc
+++ b/webrtc/base/event_tracer.cc
@@ -197,7 +197,9 @@ class EventLogger final {
 
 static bool EventTracingThreadFunc(void* params) {
   static_cast<EventLogger*>(params)->Log();
-  return true;
+  // False indicates that the thread function has done its job and doesn't need
+  // to be restarted again. Log() runs its own internal loop.
+  return false;
 }
 
 static EventLogger* volatile g_event_logger = nullptr;