[debugger] Ensure debug listeners do not throw

src/d8.cc

 // 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.
 
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 
 #include <algorithm>
@@ skipping 1789 matching lines @@
             .ToLocalChecked();
     Local<String> callback_name =
         v8::String::NewFromUtf8(isolate_, "receive", v8::NewStringType::kNormal)
             .ToLocalChecked();
     Local<Context> context = context_.Get(isolate_);
     Local<Value> callback =
         context->Global()->Get(context, callback_name).ToLocalChecked();
     if (callback->IsFunction()) {
       v8::TryCatch try_catch(isolate_);
       Local<Value> args[] = {message};
-      if (Local<Function>::Cast(callback)
-              ->Call(context, Undefined(isolate_), 1, args)
-              .IsEmpty()) {
-        try_catch.ReThrow();
-      }
+      MaybeLocal<Value> result = Local<Function>::Cast(callback)->Call(
+          context, Undefined(isolate_), 1, args);
+      CHECK(!result.IsEmpty());  // Listeners may not throw.
     }
   }
 
   Isolate* isolate_;
   Global<Context> context_;
 };
 
 class InspectorClient : public v8_inspector::V8InspectorClient {
  public:
   InspectorClient(Local<Context> context, bool connect) {
@@ skipping 1123 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif