Remove deprecated headers from mojo/public/{c,cpp}/system.

mojo/public/cpp/system/core.h

Index: mojo/public/cpp/system/core.h
diff --git a/mojo/public/cpp/system/core.h b/mojo/public/cpp/system/core.h
deleted file mode 100644
index e50fa7d8d110b08ca8de6a6fad1a5b3baeae297f..0000000000000000000000000000000000000000
--- a/mojo/public/cpp/system/core.h
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2014 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.
-
-// DEPRECATED -- do not use: include individual header files instead.
-//
-// TODO(vtl): Delete this header file.
-
-#ifndef MOJO_PUBLIC_CPP_SYSTEM_CORE_H_
-#define MOJO_PUBLIC_CPP_SYSTEM_CORE_H_
-
-#include "mojo/public/cpp/system/buffer.h"
-#include "mojo/public/cpp/system/data_pipe.h"
-#include "mojo/public/cpp/system/handle.h"
-#include "mojo/public/cpp/system/macros.h"
-#include "mojo/public/cpp/system/message_pipe.h"
-#include "mojo/public/cpp/system/time.h"
-
-#endif  // MOJO_PUBLIC_CPP_SYSTEM_CORE_H_