Linux sandbox: add test to ensure that pread64 can be forwarded.

sandbox/linux/tests/scoped_temporary_file.h

+// 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.
+
+#ifndef SANDBOX_LINUX_TESTS_SCOPED_TEMPORARY_FILE_H_
+#define SANDBOX_LINUX_TESTS_SCOPED_TEMPORARY_FILE_H_
+
+#include "base/macros.h"
+
+namespace sandbox {
+// Creates and open a temporary file on creation and closes
+// and removes it on destruction.
+// Unlike base/ helpers, this does not require JNI on Android.
+class ScopedTemporaryFile {
+ public:
+  ScopedTemporaryFile();
+  ~ScopedTemporaryFile();
+
+  int fd() const { return fd_; }
+  const char* full_file_name() const { return full_file_name_; }
+
+ private:
+  int fd_;
+  char full_file_name_[128];
+  DISALLOW_COPY_AND_ASSIGN(ScopedTemporaryFile);
+};
+
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_TESTS_SCOPED_TEMPORARY_FILE_H_