Use SetReturnUnsafe in dart_api_impl.cc.

vm/dart_api_impl.cc

 // Copyright (c) 2012, 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 "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 3700 matching lines @@
 
 
 DART_EXPORT int Dart_GetNativeArgumentCount(Dart_NativeArguments args) {
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   return arguments->Count();
 }
 
 
 DART_EXPORT void Dart_SetReturnValue(Dart_NativeArguments args,
                                      Dart_Handle retval) {
+  NoGCScope no_gc_scope;
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
-  Isolate* isolate = arguments->isolate();
-  DARTSCOPE(isolate);
-  arguments->SetReturn(Object::Handle(isolate, Api::UnwrapHandle(retval)));
+  arguments->SetReturnUnsafe(Api::UnwrapHandle(retval));
 }
 
 
 // --- Scripts and Libraries ---
 
 
 DART_EXPORT Dart_Handle Dart_SetLibraryTagHandler(
     Dart_LibraryTagHandler handler) {
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
@@ skipping 451 matching lines @@
 DART_EXPORT void Dart_InitPerfEventsSupport(Dart_FileWriterFunction function) {
   Dart::set_perf_events_writer(function);
 }
 
 
 DART_EXPORT void Dart_InitFlowGraphPrinting(Dart_FileWriterFunction function) {
   Dart::set_flow_graph_writer(function);
 }
 
 }  // namespace dart