[promises] Move PromiseReactionJob to c++

src/runtime/runtime-internal.cc

Index: src/runtime/runtime-internal.cc
diff --git a/src/runtime/runtime-internal.cc b/src/runtime/runtime-internal.cc
index b7974bcf0970f303fcf1ab230ce1dec45058199f..fcd567d3df4a68e3c59abb2c98a05b9517aee74a 100644
--- a/src/runtime/runtime-internal.cc
+++ b/src/runtime/runtime-internal.cc
@@ -571,6 +571,23 @@ RUNTIME_FUNCTION(Runtime_GetAndResetRuntimeCallStats) {
   }
 }
 
+RUNTIME_FUNCTION(Runtime_EnqueuePromiseReactionJob) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 6);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, tasks, 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, deferreds, 2);
+  CONVERT_ARG_HANDLE_CHECKED(Object, before_debug_event, 3);
+  CONVERT_ARG_HANDLE_CHECKED(Object, after_debug_event, 4);
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, reaction_context, 5);
+  Handle<PromiseHandleInfo> promise_handle_info =
+      isolate->factory()->NewPromiseHandleInfo(
+          value, tasks, deferreds, before_debug_event, after_debug_event,
+          reaction_context);

[adamk, 2016/10/11 17:56:41]

Rather than creating a function, I think you should be able to capture the
current native context here, from isolate->native_context().

+  isolate->EnqueueMicrotask(promise_handle_info);
+  return isolate->heap()->undefined_value();
+}
+
 RUNTIME_FUNCTION(Runtime_EnqueuePromiseResolveThenableJob) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 6);