Add sessions to HttpServer.

runtime/bin/crypto_linux.cc

Index: runtime/bin/crypto_linux.cc
diff --git a/runtime/bin/crypto_linux.cc b/runtime/bin/crypto_linux.cc
new file mode 100644
index 0000000000000000000000000000000000000000..08f6dacad9ae3c3391b465945760ad97f2a26d84
--- /dev/null
+++ b/runtime/bin/crypto_linux.cc
@@ -0,0 +1,18 @@
+// 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 <errno.h>
+#include <fcntl.h>
+
+#include "bin/fdutils.h"
+#include "bin/crypto.h"
+
+
+bool Crypto::GetRandomBytes(intptr_t count, uint8_t* buffer) {
+  intptr_t fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY));
+  if (fd < 0) return false;
+  intptr_t bytes_read = read(fd, buffer, count);
+  close(fd);
+  return bytes_read == count;
+}