tracing: remove sampling state profiler

third_party/WebKit/Source/platform/heap/Heap.cpp

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 49 matching lines @@
 
 class ParkThreadsScope final {
   STACK_ALLOCATED();
 
  public:
   explicit ParkThreadsScope(ThreadState* state)
       : m_state(state), m_shouldResumeThreads(false) {}
 
   bool parkThreads() {
     TRACE_EVENT0("blink_gc", "ThreadHeap::ParkThreadsScope");
-    const char* samplingState = TRACE_EVENT_GET_SAMPLING_STATE();
-    if (m_state->isMainThread())
-      TRACE_EVENT_SET_SAMPLING_STATE("blink_gc", "BlinkGCWaiting");
 
     // TODO(haraken): In an unlikely coincidence that two threads decide
     // to collect garbage at the same time, avoid doing two GCs in
     // a row and return false.
     double startTime = WTF::currentTimeMS();
 
     m_shouldResumeThreads = m_state->heap().park();
 
     double timeForStoppingThreads = WTF::currentTimeMS() - startTime;
     DEFINE_THREAD_SAFE_STATIC_LOCAL(
         CustomCountHistogram, timeToStopThreadsHistogram,
         new CustomCountHistogram("BlinkGC.TimeForStoppingThreads", 1, 1000,
                                  50));
     timeToStopThreadsHistogram.count(timeForStoppingThreads);
 
-    if (m_state->isMainThread())
-      TRACE_EVENT_SET_NONCONST_SAMPLING_STATE(samplingState);
     return m_shouldResumeThreads;
   }
 
   ~ParkThreadsScope() {
     // Only cleanup if we parked all threads in which case the GC happened
     // and we need to resume the other threads.
     if (m_shouldResumeThreads)
       m_state->heap().resume();
   }
 
@@ skipping 549 matching lines @@
   ProcessHeap::decreaseTotalMarkedObjectSize(m_stats.markedObjectSize());
 
   m_stats.reset();
   for (ThreadState* state : m_threads)
     state->resetHeapCounters();
 }
 
 ThreadHeap* ThreadHeap::s_mainThreadHeap = nullptr;
 
 }  // namespace blink