[async-iteration] add support for for-await-of loops in Async Functions

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 8ed1e3c0738ed1d3a5f4c212def5de9deb6c24a5..2969edfc76c43b13eb5ace315fd0bf9c1c53e2b7 100644
--- a/src/runtime/runtime-internal.cc
+++ b/src/runtime/runtime-internal.cc
@@ -225,6 +225,13 @@ RUNTIME_FUNCTION(Runtime_ThrowSymbolIteratorInvalid) {
       isolate, NewTypeError(MessageTemplate::kSymbolIteratorInvalid));
 }
 
+RUNTIME_FUNCTION(Runtime_ThrowSymbolAsyncIteratorInvalid) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 0);
+  THROW_NEW_ERROR_RETURN_FAILURE(
+      isolate, NewTypeError(MessageTemplate::kSymbolAsyncIteratorInvalid));
+}
+
 RUNTIME_FUNCTION(Runtime_ThrowNotGeneric) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
@@ -497,5 +504,12 @@ RUNTIME_FUNCTION(Runtime_AllowDynamicFunction) {
       Builtins::AllowDynamicFunction(isolate, target, global_proxy));
 }
 
+RUNTIME_FUNCTION(Runtime_CreateAsyncFromSyncIterator) {
+  // TODO(caitp): split AsyncFromSyncIterator functionality out of
+  //              https://codereview.chromium.org/2622833002
+  UNREACHABLE();
+  return isolate->heap()->undefined_value();
+}
+
 }  // namespace internal
 }  // namespace v8