Introduce BeforeCallEnteredCallback.

src/isolate.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include <queue>
 #include <set>
 
@@ skipping 1037 matching lines @@
     return js_calls_from_api_counter_;
   }
 
   // Get (and lazily initialize) the registry for per-isolate symbols.
   Handle<JSObject> GetSymbolRegistry();
 
   void AddCallCompletedCallback(CallCompletedCallback callback);
   void RemoveCallCompletedCallback(CallCompletedCallback callback);
   void FireCallCompletedCallback();
 
+  void AddBeforeCallEnteredCallback(BeforeCallEnteredCallback callback);
+  void RemoveBeforeCallEnteredCallback(BeforeCallEnteredCallback callback);
+  void FireBeforeCallEnteredCallback();
+
   void SetPromiseRejectCallback(PromiseRejectCallback callback);
   void ReportPromiseReject(Handle<JSObject> promise, Handle<Object> value,
                            v8::PromiseRejectEvent event);
 
   void EnqueueMicrotask(Handle<Object> microtask);
   void RunMicrotasks();
 
   void SetUseCounterCallback(v8::Isolate::UseCounterCallback callback);
   void CountUsage(v8::Isolate::UseCounterFeature feature);
 
@@ skipping 243 matching lines @@
 
   int next_optimization_id_;
 
   // Counts javascript calls from the API. Wraps around on overflow.
   unsigned int js_calls_from_api_counter_;
 
 #if TRACE_MAPS
   int next_unique_sfi_id_;
 #endif
 
+  // List of callbacks before a Call starts execution.
+  List<BeforeCallEnteredCallback> before_call_entered_callbacks_;
+
   // List of callbacks when a Call completes.
   List<CallCompletedCallback> call_completed_callbacks_;
 
   v8::Isolate::UseCounterCallback use_counter_callback_;
   BasicBlockProfiler* basic_block_profiler_;
 
   List<Object*> partial_snapshot_cache_;
 
   v8::ArrayBuffer::Allocator* array_buffer_allocator_;
 
@@ skipping 226 matching lines @@
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ISOLATE_H_