Hibernate the thread if there are no events in the queue. Wake it up when an event is added to the …

webrtc/call/rtc_event_log_helper_thread.h

Index: webrtc/call/rtc_event_log_helper_thread.h
diff --git a/webrtc/call/rtc_event_log_helper_thread.h b/webrtc/call/rtc_event_log_helper_thread.h
index 60ed912b65163a22971272c8b9ab05cd4fcc5e89..2d5a78586dae0f02e7c29315dd11ae35c7d685a7 100644
--- a/webrtc/call/rtc_event_log_helper_thread.h
+++ b/webrtc/call/rtc_event_log_helper_thread.h
@@ -67,22 +67,27 @@ class RtcEventLogHelperThread final {
   RtcEventLogHelperThread(
       SwapQueue<ControlMessage>* message_queue,
       SwapQueue<std::unique_ptr<rtclog::Event>>* event_queue,
-      rtc::Event* wake_up,
-      rtc::Event* file_finished,
       const Clock* const clock);
   ~RtcEventLogHelperThread();
 
+  // This function MUST be called once a STOP_FILE message is added to the
+  // signalling queue. The function will make sure that the output thread
+  // wakes up to read the message, and it blocks until the output thread has
+  // finished writing to the file.
+  void WaitForFileFinished();
+
+  // This fuction MUST be called once an event is added to the event queue.
+  void SignalNewEvent();
+
  private:
   static bool ThreadOutputFunction(void* obj);
 
-  void TerminateThread();
   bool AppendEventToString(rtclog::Event* event);
-  void AppendEventToHistory(const rtclog::Event& event);
-  void LogToMemory();
+  bool LogToMemory();
   void StartLogFile();
-  void LogToFile();
+  bool LogToFile();
   void StopLogFile();
-  void WriteLog();
+  void ProcessEvents();
 
   // Message queues for passing events to the logging thread.
   SwapQueue<ControlMessage>* message_queue_;
@@ -108,8 +113,9 @@ class RtcEventLogHelperThread final {
   // Temporary space for serializing profobuf data.
   std::string output_string_;
 
-  rtc::Event* wake_up_;
-  rtc::Event* stopped_;
+  rtc::Event wake_periodically_;
+  rtc::Event wake_from_hibernation_;
+  rtc::Event file_finished_;
 
   const Clock* const clock_;