Set up for mac native secure sockets

runtime/bin/secure_socket_macos.h

Index: runtime/bin/secure_socket_macos.h
diff --git a/runtime/bin/secure_socket_macos.h b/runtime/bin/secure_socket_macos.h
new file mode 100644
index 0000000000000000000000000000000000000000..5566f8ec23242f9e7aa325e92b05d33c2ac5b97b
--- /dev/null
+++ b/runtime/bin/secure_socket_macos.h
@@ -0,0 +1,38 @@
+// Copyright (c) 2016, 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 BIN_SECURE_SOCKET_MACOS_H_
+#define BIN_SECURE_SOCKET_MACOS_H_
+
+#if !defined(BIN_SECURE_SOCKET_H_)
+#error Do not include secure_socket_macos.h directly. Use secure_socket.h.
+#endif
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/SecureTransport.h>
+#include <Security/Security.h>
+
+#include "bin/dartutils.h"
+
+namespace dart {
+namespace bin {
+
+// SSLFilter encapsulates the SecureTransport code in a filter that communicates
+// with the containing _SecureFilterImpl Dart object through four shared
+// ExternalByteArray buffers, for reading and writing plaintext, and
+// reading and writing encrypted text.  The filter handles handshaking
+// and certificate verification.
+class SSLFilter {
+ public:
+  // Callback called by the IOService.
+  static CObject* ProcessFilterRequest(const CObjectArray& request);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SSLFilter);
+};
+
+}  // namespace bin
+}  // namespace dart
+
+#endif  // BIN_SECURE_SOCKET_MACOS_H_