Store API callback entry address prior to entering a callback.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index fa1b34e655fe3aaa752bed7561e382ad3d307322..b66635c500cfbc450d504ded81bacfe6e72fa812 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -380,6 +380,9 @@ BUILTIN(HandleApiCall) {
     {
       // Leaving JavaScript.
       VMState state(EXTERNAL);
+#ifdef ENABLE_LOGGING_AND_PROFILING
+      state.set_external_callback(v8::ToCData<Address>(callback_obj));
+#endif
       value = callback(new_args);
     }
     if (value.IsEmpty()) {
@@ -446,6 +449,9 @@ static Object* HandleApiCallAsFunctionOrConstructor(bool is_construct_call,
     {
       // Leaving JavaScript.
       VMState state(EXTERNAL);
+#ifdef ENABLE_LOGGING_AND_PROFILING
+      state.set_external_callback(v8::ToCData<Address>(callback_obj));
+#endif
       value = callback(new_args);
     }
     if (value.IsEmpty()) {