Fix performance issue in InstanceCounters for DOM nodes

third_party/WebKit/Source/core/inspector/InstanceCounters.h

 /*
 * Copyright (C) 2012 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 44 matching lines @@
     ResourceCounter,
     ScriptPromiseCounter,
     V8PerContextDataCounter,
     WorkerGlobalScopeCounter,
 
     // This value must be the last.
     CounterTypeLength,
   };
 
   static inline void incrementCounter(CounterType type) {
+    DCHECK_NE(type, NodeCounter);
     atomicIncrement(&s_counters[type]);
   }
 
   static inline void decrementCounter(CounterType type) {
+    DCHECK_NE(type, NodeCounter);
     atomicDecrement(&s_counters[type]);
   }
 
+  static inline void incrementNodeCounter() {
+    DCHECK(isMainThread());
+    s_nodeCounter++;
+  }
+
+  static inline void decrementNodeCounter() {
+    DCHECK(isMainThread());
+    s_nodeCounter--;
+  }
+
   CORE_EXPORT static int counterValue(CounterType);
 
  private:
   CORE_EXPORT static int s_counters[CounterTypeLength];
+  CORE_EXPORT static int s_nodeCounter;
 };
 
 }  // namespace blink
 
 #endif  // !defined(InstanceCounters_h)