Allow recursive messages reporting as it is already used.

src/messages.cc

Index: src/messages.cc
diff --git a/src/messages.cc b/src/messages.cc
index 0cc82512c42842166fc24c92c8c1faf9e50b6d9c..abc25377851b5c4a76a404b5519edf75adc70226 100644
--- a/src/messages.cc
+++ b/src/messages.cc
@@ -104,15 +104,6 @@ Handle<JSMessageObject> MessageHandler::MakeMessageObject(
 void MessageHandler::ReportMessage(Isolate* isolate,
                                    MessageLocation* loc,
                                    Handle<Object> message) {
-  // If we are in process of message reporting, just ignore all other requests
-  // to report a message as they are due to unhandled exceptions thrown in
-  // message callbacks.
-  if (isolate->in_exception_reporting()) {
-    PrintF("uncaught exception thrown while reporting\n");
-    return;
-  }
-  isolate->set_in_exception_reporting(true);
-
   // We are calling into embedder's code which can throw exceptions.
   // Thus we need to save current exception state, reset it to the clean one
   // and ignore scheduled exceptions callbacks can throw.
@@ -138,14 +129,16 @@ void MessageHandler::ReportMessage(Isolate* isolate,
       v8::MessageCallback callback =
           FUNCTION_CAST<v8::MessageCallback>(callback_obj->proxy());
       Handle<Object> callback_data(listener.get(1));
-      callback(api_message_obj, v8::Utils::ToLocal(callback_data));
+      {
+        // Do not allow exceptions to propagate.
+        v8::TryCatch tryCatch;
+        callback(api_message_obj, v8::Utils::ToLocal(callback_data));
+      }
       if (isolate->has_scheduled_exception()) {
         isolate->clear_scheduled_exception();
       }
     }
   }
-
-  isolate->set_in_exception_reporting(false);
 }