Mojo: Move public C system header files to mojo/public/c/system/.

mojo/public/system/system_export.h

Index: mojo/public/system/system_export.h
diff --git a/mojo/public/system/system_export.h b/mojo/public/system/system_export.h
deleted file mode 100644
index 6b563ff13372be825672837e71a19ad826e22496..0000000000000000000000000000000000000000
--- a/mojo/public/system/system_export.h
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright 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 MOJO_PUBLIC_SYSTEM_SYSTEM_EXPORT_H_
-#define MOJO_PUBLIC_SYSTEM_SYSTEM_EXPORT_H_
-
-#if defined(WIN32)
-
-#if defined(MOJO_SYSTEM_IMPLEMENTATION)
-#define MOJO_SYSTEM_EXPORT __declspec(dllexport)
-#else
-#define MOJO_SYSTEM_EXPORT __declspec(dllimport)
-#endif
-
-#else  // !defined(WIN32)
-
-#if defined(MOJO_SYSTEM_IMPLEMENTATION)
-#define MOJO_SYSTEM_EXPORT __attribute__((visibility("default")))
-#else
-#define MOJO_SYSTEM_EXPORT
-#endif
-
-#endif  // defined(WIN32)
-
-#endif  // MOJO_PUBLIC_SYSTEM_SYSTEM_EXPORT_H_