Add RequestOSFileHandle as a private PPAPI

ppapi/cpp/private/file_io_private.h

Index: ppapi/cpp/private/file_io_private.h
diff --git a/ppapi/cpp/private/file_io_private.h b/ppapi/cpp/private/file_io_private.h
new file mode 100644
index 0000000000000000000000000000000000000000..c291be564bc6e9b1e233a6289e2aba4bb42e75c9
--- /dev/null
+++ b/ppapi/cpp/private/file_io_private.h
@@ -0,0 +1,42 @@
+// 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 PPAPI_CPP_PRIVATE_FILE_IO_PRIVATE_H_
+#define PPAPI_CPP_PRIVATE_FILE_IO_PRIVATE_H_
+
+#include "ppapi/c/pp_stdint.h"
+#include "ppapi/c/private/pp_file_handle.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/file_io.h"
+
+namespace pp {
+
+class FileIO;
+
+class FileIO_Private : public FileIO {
+ public:
+  FileIO_Private();
+  explicit FileIO_Private(const InstanceHandle& instance);
+
+  // This interface may leak the memory and file handle if the factory
+  // of |cc| is destructed.  We need to use
+  // CompletionCallbackWithOutput to prevent the memory leak and
+  // create something like PassFileHandle to prevent the handle leak.
+  // See https://codereview.chromium.org/13032002/#ps33001
+  //
+  // Currently, TestCompletionCallbackWithOutput won't work for non
+  // vector types, so we should fix it first.
+  // http://crbug.com/224741
+  //
+  // Meanwhile, this interface should be used only from tests and
+  // other code should use the C interface of this API.
+  //
+  // TODO(hamaji): Fix. http://crbug.com/224745
+  int32_t RequestOSFileHandle(PP_FileHandle* result_handle,
+                              const CompletionCallback& cc);
+};
+
+}  // namespace pp
+
+#endif  // PPAPI_CPP_PRIVATE_FILE_IO_PRIVATE_H_