Fixes leak of native File objects.

runtime/bin/dartutils.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 "bin/dartutils.h"
 
 #include "bin/crypto.h"
 #include "bin/directory.h"
 #include "bin/extensions.h"
 #include "bin/file.h"
@@ skipping 204 matching lines @@
                           intptr_t num_bytes,
                           void* stream) {
   ASSERT(stream != NULL);
   File* file_stream = reinterpret_cast<File*>(stream);
   bool bytes_written = file_stream->WriteFully(buffer, num_bytes);
   ASSERT(bytes_written);
 }
 
 
 void DartUtils::CloseFile(void* stream) {
-  delete reinterpret_cast<File*>(stream);
+  File* file = reinterpret_cast<File*>(stream);
+  file->Release();
 }
 
 
 bool DartUtils::EntropySource(uint8_t* buffer, intptr_t length) {
   return Crypto::GetRandomBytes(length, buffer);
 }
 
 
 static Dart_Handle SingleArgDart_Invoke(Dart_Handle lib, const char* method,
                                         Dart_Handle arg) {
@@ skipping 1019 matching lines @@
       new CObjectString(CObject::NewString(os_error->message()));
   CObjectArray* result = new CObjectArray(CObject::NewArray(3));
   result->SetAt(0, new CObjectInt32(CObject::NewInt32(kOSError)));
   result->SetAt(1, new CObjectInt32(CObject::NewInt32(os_error->code())));
   result->SetAt(2, error_message);
   return result;
 }
 
 }  // namespace bin
 }  // namespace dart