Changes to get rid of dependency on openssl in the dart VM.

vm/bigint_store.h

-// 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.
-
-#ifndef VM_BIGINT_STORE_H_
-#define VM_BIGINT_STORE_H_
-
-#include "vm/globals.h"
-#include "vm/isolate.h"
-
-namespace dart {
-
-// Use to store teporary BIGNUMs.
-class BigintStore {
- public:
-  BigintStore() : bn_(NULL), bn_ctx_(NULL) {}
-  ~BigintStore() {
-    BN_free(bn_);
-    BN_CTX_free(bn_ctx_);
-  }
-
-  static BigintStore* Get() {
-    BigintStore* store = Isolate::Current()->bigint_store();
-    if (store == NULL) {
-      store = new BigintStore();
-      Isolate::Current()->set_bigint_store(store);
-    }
-    return store;
-  }
-
-  BIGNUM* bn_;
-  BN_CTX* bn_ctx_;
-};
-
-}  // namespace dart
-
-#endif  // VM_BIGINT_STORE_H_