Conditionally bail out earlier in Heap::reportMemoryUsageForTracing()

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 2382 matching lines @@
     if (sizeInMB > observedMaxSizeInMB) {
         // Send a UseCounter only when we see the highest memory usage
         // we've ever seen.
         Platform::current()->histogramEnumeration("BlinkGC.CommittedSize", sizeInMB, supportedMaxSizeInMB);
         observedMaxSizeInMB = sizeInMB;
     }
 }
 
 void Heap::reportMemoryUsageForTracing()
 {
+    bool gcTracingEnabled;
+    TRACE_EVENT_CATEGORY_GROUP_ENABLED("blink_gc", &gcTracingEnabled);
+    if (!gcTracingEnabled)
+        return;
+
     // These values are divided by 1024 to avoid overflow in practical cases (TRACE_COUNTER values are 32-bit ints).
     // They are capped to INT_MAX just in case.
     TRACE_COUNTER1("blink_gc", "Heap::allocatedObjectSizeKB", std::min(Heap::allocatedObjectSize() / 1024, static_cast<size_t>(INT_MAX)));
     TRACE_COUNTER1("blink_gc", "Heap::markedObjectSizeKB", std::min(Heap::markedObjectSize() / 1024, static_cast<size_t>(INT_MAX)));
     TRACE_COUNTER1("blink_gc", "Heap::allocatedSpaceKB", std::min(Heap::allocatedSpace() / 1024, static_cast<size_t>(INT_MAX)));
     TRACE_COUNTER1("blink_gc", "Heap::objectSizeAtLastGCKB", std::min(Heap::objectSizeAtLastGC() / 1024, static_cast<size_t>(INT_MAX)));
     TRACE_COUNTER1("blink_gc", "Heap::persistentCount", std::min(Heap::persistentCount(), static_cast<size_t>(INT_MAX)));
     TRACE_COUNTER1("blink_gc", "Heap::persistentCountAtLastGC", std::min(Heap::persistentCountAtLastGC(), static_cast<size_t>(INT_MAX)));
     TRACE_COUNTER1("blink_gc", "Heap::collectedPersistentCount", std::min(Heap::collectedPersistentCount(), static_cast<size_t>(INT_MAX)));
     TRACE_COUNTER1("blink_gc", "Heap::heapSizePerPersistent", std::min(Heap::heapSizePerPersistent(), static_cast<size_t>(INT_MAX)));
@@ skipping 135 matching lines @@
 size_t Heap::s_objectSizeAtLastGC = 0;
 size_t Heap::s_markedObjectSize = 0;
 size_t Heap::s_persistentCount = 0;
 size_t Heap::s_persistentCountAtLastGC = 0;
 size_t Heap::s_collectedPersistentCount = 0;
 size_t Heap::s_partitionAllocSizeAtLastGC = 0;
 size_t Heap::s_heapSizePerPersistent = 0;
 double Heap::s_estimatedMarkingTimePerByte = 0.0;
 
 } // namespace blink