Await always waits

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
@@ skipping 1858 matching lines @@
   return Api::ClassId(handle) == kByteBufferCid;
 }
 
 
 DART_EXPORT bool Dart_IsFuture(Dart_Handle handle) {
   TRACE_API_CALL(CURRENT_FUNC);
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(handle));
   if (obj.IsInstance()) {
-    const Library& async_lib =
-        Library::Handle(isolate, Library::AsyncLibrary());
     const Class& future_class =
-        Class::Handle(isolate, async_lib.LookupClass(Symbols::Future()));
+        Class::Handle(isolate->object_store()->future_class());
     ASSERT(!future_class.IsNull());
     const Class& obj_class = Class::Handle(isolate, obj.clazz());
     Error& malformed_type_error = Error::Handle(isolate);
     bool is_future = obj_class.IsSubtypeOf(Object::null_type_arguments(),
                                            future_class,
                                            Object::null_type_arguments(),
                                            &malformed_type_error);
     ASSERT(malformed_type_error.IsNull());  // Type is a raw Future.
     return is_future;
   }
@@ skipping 3515 matching lines @@
 
 
 DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterRootEmbedderCallback(name, callback, user_data);
 }
 
 }  // namespace dart