Add a get_random_bytes() syscall to replace the SRPC-based implementation

src/trusted/service_runtime/sys_random.h

+/*
+ * Copyright (c) 2014 The Native Client 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 NATIVE_CLIENT_SERVICE_RUNTIME_NACL_SYS_RANDOM_H_
+#define NATIVE_CLIENT_SERVICE_RUNTIME_NACL_SYS_RANDOM_H_ 1
+
+#include "native_client/src/include/nacl_base.h"
+#include "native_client/src/include/portability.h"
+
+EXTERN_C_BEGIN
+
+struct NaClAppThread;
+
+int32_t NaClSysGetRandomBytes(struct NaClAppThread *natp,
+                              uint32_t buf_addr, uint32_t buf_size);
+
+EXTERN_C_END
+
+#endif