Trace tracing Start/Stop events.

webrtc/base/event_tracer.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "webrtc/base/event_tracer.h"
@@ skipping 121 matching lines @@
       if (shutting_down)
         break;
     }
     fprintf(output_file_, "]}\n");
     if (output_file_owned_)
       fclose(output_file_);
     output_file_ = nullptr;
   }
 
   void Start(FILE* file, bool owned) {
+    RTC_DCHECK(thread_checker_.CalledOnValidThread());
     RTC_DCHECK(file);
     RTC_DCHECK(!output_file_);
     output_file_ = file;
     output_file_owned_ = owned;
     {
       rtc::CritScope lock(&crit_);
       // Since the atomic fast-path for adding events to the queue can be
       // bypassed while the logging thread is shutting down there may be some
       // stale events in the queue, hence the vector needs to be cleared to not
       // log events from a previous logging session (which may be days old).
       trace_events_.clear();
     }
     // Enable event logging (fast-path). This should be disabled since starting
     // shouldn't be done twice.
     RTC_CHECK_EQ(0,
                  rtc::AtomicOps::CompareAndSwap(&g_event_logging_active, 0, 1));
 
     // Finally start, everything should be set up now.
     logging_thread_.Start();
+    TRACE_EVENT_INSTANT0("webrtc", "EventLogger::Start");
   }
 
   void Stop() {
+    RTC_DCHECK(thread_checker_.CalledOnValidThread());
+    TRACE_EVENT_INSTANT0("webrtc", "EventLogger::Stop");
     // Try to stop. Abort if we're not currently logging.
     if (rtc::AtomicOps::CompareAndSwap(&g_event_logging_active, 1, 0) == 0)
       return;
 
     // Wake up logging thread to finish writing.
     shutdown_event_.Set();
     // Join the logging thread.
     logging_thread_.Stop();
   }
 
@@ skipping 87 matching lines @@
   RTC_DCHECK(old_logger);
   RTC_CHECK(rtc::AtomicOps::CompareAndSwapPtr(
                 &g_event_logger, old_logger,
                 static_cast<EventLogger*>(nullptr)) == old_logger);
   delete old_logger;
   webrtc::SetupEventTracer(nullptr, nullptr);
 }
 
 }  // namespace tracing
 }  // namespace rtc