Use the distinguished class, ApiFailure, to signal when a Dart_Result is

runtime/vm/raw_object.cc

 // Copyright (c) 2011, 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 "vm/raw_object.h"
 
 #include "vm/object.h"
 #include "vm/visitor.h"
 
 
@@ skipping 323 matching lines @@
 }
 
 
 intptr_t RawUnhandledException::VisitUnhandledExceptionPointers(
     RawUnhandledException* raw_obj, ObjectPointerVisitor* visitor) {
   visitor->VisitPointers(raw_obj->from(), raw_obj->to());
   return UnhandledException::InstanceSize();
 }
 
 
+intptr_t RawApiFailure::VisitApiFailurePointers(
+    RawApiFailure* raw_obj, ObjectPointerVisitor* visitor) {
+  visitor->VisitPointers(raw_obj->from(), raw_obj->to());
+  return ApiFailure::InstanceSize();
+}
+
+
 intptr_t RawInstance::VisitInstancePointers(RawInstance* raw_obj,
                                             ObjectPointerVisitor* visitor) {
   // Make sure that we got here with the tagged pointer as this.
   ASSERT(raw_obj->IsHeapObject());
   RawInstance* obj = raw_obj->ptr();
   intptr_t instance_size = obj->class_->ptr()->instance_size_;
   intptr_t num_native_fields = obj->class_->ptr()->num_native_fields_;
 
   // Calculate the first and last raw object pointer fields.
   uword obj_addr = RawObject::ToAddr(raw_obj);
@@ skipping 129 matching lines @@
 intptr_t RawJSRegExp::VisitJSRegExpPointers(RawJSRegExp* raw_obj,
                                             ObjectPointerVisitor* visitor) {
   // Make sure that we got here with the tagged pointer as this.
   ASSERT(raw_obj->IsHeapObject());
   intptr_t length = Smi::Value(raw_obj->ptr()->data_length_);
   visitor->VisitPointers(raw_obj->from(), raw_obj->to());
   return JSRegExp::InstanceSize(length);
 }
 
 }  // namespace dart