Trace where timers were scheduled in Blink

Source/platform/ThreadTimers.cpp

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 104 matching lines @@
     // Do a re-entrancy check.
     if (m_firingTimers)
         return;
     m_firingTimers = true;
     m_pendingSharedTimerFireTime = 0;
 
     double fireTime = monotonicallyIncreasingTime();
     double timeToQuit = fireTime + maxDurationOfFiringTimers;
 
     while (!m_timerHeap.isEmpty() && m_timerHeap.first()->m_nextFireTime <= fireTime) {
-        TimerBase* timer = m_timerHeap.first();
-        timer->m_nextFireTime = 0;
-        timer->m_unalignedNextFireTime = 0;
-        timer->heapDeleteMin();
+        TimerBase& timer = *m_timerHeap.first();
+        timer.m_nextFireTime = 0;
+        timer.m_unalignedNextFireTime = 0;
+        timer.heapDeleteMin();
 
-        double interval = timer->repeatInterval();
-        timer->setNextFireTime(interval ? fireTime + interval : 0);
+        double interval = timer.repeatInterval();
+        timer.setNextFireTime(interval ? fireTime + interval : 0);
+
+        TRACE_EVENT2("blink", "ThreadTimers::sharedTimerFiredInternal",
+            "src_file", timer.location().fileName(),
+            "src_func", timer.location().functionName());
 
         // Once the timer has been fired, it may be deleted, so do nothing else with it after this point.
-        timer->fired();
+        timer.fired();
 
         // Catch the case where the timer asked timers to fire in a nested event loop, or we are over time limit.
         if (!m_firingTimers || timeToQuit < monotonicallyIncreasingTime())
             break;
     }
 
     m_firingTimers = false;
 
     updateSharedTimer();
 }
 
 void ThreadTimers::fireTimersInNestedEventLoop()
 {
     // Reset the reentrancy guard so the timers can fire again.
     m_firingTimers = false;
     updateSharedTimer();
 }
 
 } // namespace WebCore