[async-iteration] implement Async-from-Sync Iterator

src/factory.cc

 // Copyright 2014 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 "src/factory.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast.h"
 #include "src/base/bits.h"
@@ skipping 1940 matching lines @@
 Handle<JSIteratorResult> Factory::NewJSIteratorResult(Handle<Object> value,
                                                       bool done) {
   Handle<Map> map(isolate()->native_context()->iterator_result_map());
   Handle<JSIteratorResult> js_iter_result =
       Handle<JSIteratorResult>::cast(NewJSObjectFromMap(map));
   js_iter_result->set_value(*value);
   js_iter_result->set_done(*ToBoolean(done));
   return js_iter_result;
 }
 
+Handle<JSAsyncFromSyncIterator> Factory::NewJSAsyncFromSyncIterator(
+    Handle<HeapObject> sync_iterator) {
+  Handle<Map> map(isolate()->native_context()->async_from_sync_iterator_map());
+  Handle<JSAsyncFromSyncIterator> iterator =
+      Handle<JSAsyncFromSyncIterator>::cast(NewJSObjectFromMap(map));
+
+  iterator->set_sync_iterator(*sync_iterator);
+  return iterator;
+}
+
 Handle<JSMap> Factory::NewJSMap() {
   Handle<Map> map(isolate()->native_context()->js_map_map());
   Handle<JSMap> js_map = Handle<JSMap>::cast(NewJSObjectFromMap(map));
   JSMap::Initialize(js_map, isolate());
   return js_map;
 }
 
 
 Handle<JSSet> Factory::NewJSSet() {
   Handle<Map> map(isolate()->native_context()->js_set_map());
@@ skipping 871 matching lines @@
     Handle<AccessorInfo> prototype =
         Accessors::FunctionPrototypeInfo(isolate(), rw_attribs);
     Descriptor d = Descriptor::AccessorConstant(
         Handle<Name>(Name::cast(prototype->name())), prototype, rw_attribs);
     map->AppendDescriptor(&d);
   }
 }
 
 }  // namespace internal
 }  // namespace v8