Implement spawnFunction from the new isolate api.

runtime/vm/zone.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 "vm/zone.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
 #include "vm/isolate.h"
@@ skipping 225 matching lines @@
 
 
 void Zone::VisitObjectPointers(ObjectPointerVisitor* visitor) {
   Zone* zone = this;
   while (zone != NULL) {
     zone->handles()->VisitObjectPointers(visitor);
     zone = zone->previous_;
   }
 }
 
+
+char* Zone::PrintToString(const char* format, ...) {
+  va_list args;
+  va_start(args, format);
+  intptr_t len = OS::VSNPrint(NULL, 0, format, args);
+  va_end(args);
+
+  char* buffer = reinterpret_cast<char*>(Allocate(len + 1));
+  va_list args2;
+  va_start(args2, format);
+  OS::VSNPrint(buffer, (len + 1), format, args2);
+  va_end(args2);
+
+  return buffer;
+}
+
+
 }  // namespace dart