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

sandbox/linux/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 
 declare_args() {
   compile_suid_client = is_linux
 
   compile_credentials = is_linux
@@ skipping 48 matching lines @@
     ]
     deps += [
       ":seccomp_bpf",
     ]
   }
 }
 
 # The main sandboxing test target.
 test("sandbox_linux_unittests") {
   sources = [
-    "tests/main.cc",
-    "tests/unit_tests_unittest.cc",
     "services/broker_process_unittest.cc",
     "services/scoped_process_unittest.cc",
     "services/thread_helpers_unittests.cc",
     "services/yama_unittests.cc",
+    "tests/main.cc",
+    "tests/scoped_temporary_file.cc",
+    "tests/scoped_temporary_file.h",
+    "tests/scoped_temporary_file_unittest.cc",
+    "tests/unit_tests_unittest.cc",
   ]
 
   deps = [
     ":sandbox",
     ":sandbox_linux_test_utils",
     "//base",
     "//base/test:test_support",
     "//testing/gtest",
   ]
 
@@ skipping 220 matching lines @@
   #      'type': 'none',
   #      'variables': {
   #        'test_suite_name': 'sandbox_linux_jni_unittests',
   #      },
   #      'dependencies': [
   #        'sandbox_linux_jni_unittests',
   #      ],
   #      'includes': [ '../../build/apk_test.gypi' ],
   #      }
 }