[NaCl SDK] nacl_io: big refactor to return error value (errno).

native_client_sdk/src/libraries/nacl_io/error.h

Index: native_client_sdk/src/libraries/nacl_io/error.h
diff --git a/native_client_sdk/src/libraries/nacl_io/error.h b/native_client_sdk/src/libraries/nacl_io/error.h
new file mode 100644
index 0000000000000000000000000000000000000000..8f7510e46e47d578ab933ab689d5891277631ea5
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/error.h
@@ -0,0 +1,17 @@
+/* Copyright (c) 2013 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 LIBRARIES_NACL_IO_ERROR_H_
+#define LIBRARIES_NACL_IO_ERROR_H_
+
+struct Error {
+  // TODO(binji): Add debugging constructor w/ __FILE__, __LINE__.
+  // crbug.com/247816
+  Error(int error) : error(error) {}
+  operator int() const { return error; }
+
+  int error;
+};
+
+#endif  // LIBRARIES_NACL_IO_ERROR_H_