Share the zygote's fopen overrides with nacl_helper.

sandbox/linux/services/libc_urandom_override.h

Index: sandbox/linux/services/libc_urandom_override.h
diff --git a/sandbox/linux/services/libc_urandom_override.h b/sandbox/linux/services/libc_urandom_override.h
new file mode 100644
index 0000000000000000000000000000000000000000..1990313b9c0f359683f14b7d61370388abdaae55
--- /dev/null
+++ b/sandbox/linux/services/libc_urandom_override.h
@@ -0,0 +1,18 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SANDBOX_LINUX_SERVICES_LIBC_URANDOM_OVERRIDE_H_
+#define SANDBOX_LINUX_SERVICES_LIBC_URANDOM_OVERRIDE_H_
+
+namespace sandbox {
+
+#if !defined(CHROMIUM_SELINUX)
+
+void InitLibcUrandomOverrides();
+
+#endif  // !CHROMIUM_SELINUX
+
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_SERVICES_LIBC_URANDOM_OVERRIDE_H_