Add a use counter API

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 3cabea9c8549bc35a81ac4c082769d78c1d8c6b5..2a1187361f5a1bcda9f6659b6b8a9bb097a29380 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -1081,6 +1081,9 @@ class Isolate {
   void EnqueueMicrotask(Handle<Object> microtask);
   void RunMicrotasks();
 
+  void SetUseCounterCallback(v8::Isolate::UseCounterCallback callback);
+  void CountUsage(v8::Isolate::UseCounterFeature feature);
+
  private:
   Isolate();
 
@@ -1300,6 +1303,8 @@ class Isolate {
   // List of callbacks when a Call completes.
   List<CallCompletedCallback> call_completed_callbacks_;
 
+  v8::Isolate::UseCounterCallback use_counter_callback_;
+
   friend class ExecutionAccess;
   friend class HandleScopeImplementer;
   friend class IsolateInitializer;