[Not for review] Add traces for crbug.com/726626

third_party/WebKit/Source/core/timing/PerformanceBase.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 27 matching lines @@
 #include "core/frame/LocalFrame.h"
 #include "core/frame/UseCounter.h"
 #include "core/loader/DocumentLoadTiming.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/timing/PerformanceLongTaskTiming.h"
 #include "core/timing/PerformanceObserver.h"
 #include "core/timing/PerformanceResourceTiming.h"
 #include "core/timing/PerformanceServerTiming.h"
 #include "core/timing/PerformanceUserTiming.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/loader/fetch/ResourceResponse.h"
 #include "platform/loader/fetch/ResourceTimingInfo.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "platform/wtf/CurrentTime.h"
 
 namespace blink {
 
 namespace {
 
 SecurityOrigin* GetSecurityOrigin(ExecutionContext* context) {
@@ skipping 539 matching lines @@
       ClampTimeResolution(time_in_seconds));
 }
 
 DOMHighResTimeStamp PerformanceBase::MonotonicTimeToDOMHighResTimeStamp(
     double monotonic_time) const {
   return MonotonicTimeToDOMHighResTimeStamp(time_origin_, monotonic_time,
                                             false /* allow_negative_value */);
 }
 
 DOMHighResTimeStamp PerformanceBase::now() const {
+  TRACE_EVENT0("ServiceWorker", "PerformanceBase::now");
   return MonotonicTimeToDOMHighResTimeStamp(MonotonicallyIncreasingTime());
 }
 
 DEFINE_TRACE(PerformanceBase) {
   visitor->Trace(frame_timing_buffer_);
   visitor->Trace(resource_timing_buffer_);
   visitor->Trace(navigation_timing_);
   visitor->Trace(user_timing_);
   visitor->Trace(server_timing_buffer_);
   visitor->Trace(first_paint_timing_);
   visitor->Trace(first_contentful_paint_timing_);
   visitor->Trace(observers_);
   visitor->Trace(active_observers_);
   visitor->Trace(suspended_observers_);
   EventTargetWithInlineData::Trace(visitor);
 }
 
 }  // namespace blink