Fix an incorrect usage of reusable handles in Dart_Allocate.

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/bigint_operations.h"
@@ skipping 3099 matching lines @@
 DART_EXPORT Dart_Handle Dart_Allocate(Dart_Handle type) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   CHECK_CALLBACK_STATE(isolate);
 
   const Type& type_obj = Api::UnwrapTypeHandle(isolate, type);
   // Get the class to instantiate.
   if (type_obj.IsNull()) {
     RETURN_TYPE_ERROR(isolate, type, Type);
   }
-  REUSABLE_CLASS_HANDLESCOPE(isolate);
-  Class& cls = isolate->ClassHandle();
-  cls = type_obj.type_class();
-
+  const Class& cls = Class::Handle(isolate, type_obj.type_class());
   if (!cls.is_fields_marked_nullable()) {
     // Mark all fields as nullable.
     Class& iterate_cls = Class::Handle(isolate, cls.raw());
     Field& field = Field::Handle(isolate);
     Array& fields = Array::Handle(isolate);
     while (!iterate_cls.IsNull()) {
       iterate_cls.set_is_fields_marked_nullable();
       fields = iterate_cls.fields();
       iterate_cls = iterate_cls.SuperClass();
       for (int field_num = 0; field_num < fields.Length(); field_num++) {
         field ^= fields.At(field_num);
         if (field.is_static()) {
           continue;
         }
         field.UpdateGuardedCidAndLength(Object::null_object());
       }
     }
   }
 
-  REUSABLE_ERROR_HANDLESCOPE(isolate);
-  Error& error = isolate->ErrorHandle();
-  error = cls.EnsureIsFinalized(isolate);
+  const Error& error = Error::Handle(isolate, cls.EnsureIsFinalized(isolate));
   if (!error.IsNull()) {
     // An error occurred, return error object.
     return Api::NewHandle(isolate, error.raw());
   }
   // Allocate an object for the given class.
   return Api::NewHandle(isolate, Instance::New(cls));
 }
 
 
 static Dart_Handle SetupArguments(Isolate* isolate,
@@ skipping 1477 matching lines @@
 
 
 DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterRootEmbedderCallback(name, callback, user_data);
 }
 
 }  // namespace dart