Add FileIOTrusted class.

ppapi/cpp/trusted/file_io_trusted.h

+// Copyright (c) 2011 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_TRUSTED_FILE_IO_TRUSTED_H_
+#define PPAPI_CPP_TRUSTED_FILE_IO_TRUSTED_H_
+
+#include <string>
+
+#include "ppapi/c/pp_stdint.h"
+
+namespace pp {
+
+class FileIO;
+class CompletionCallback;
+
+class FileIO_Trusted {
+ public:
+  /// Creates a FileIO_Trusted object.
+  FileIO_Trusted();
+
+  int32_t GetOSFileDescriptor(const FileIO& file_io);
+
+  int32_t WillWrite(const FileIO& file_io,
+                    int64_t offset,
+                    int32_t bytes_to_write,
+                    const CompletionCallback& callback);
+
+  int32_t WillSetLength(const FileIO& file_io,
+                        int64_t length,
+                        const CompletionCallback& callback);
+};
+
+}  // namespace pp
+
+#endif  // PPAPI_CPP_TRUSTED_FILE_IO_TRUSTED_H_