Move a couple of utility functions to a new namespace_utils class.

sandbox/linux/services/namespace_utils.h

Index: sandbox/linux/services/namespace_utils.h
diff --git a/sandbox/linux/services/namespace_utils.h b/sandbox/linux/services/namespace_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..61c3f1307d71edec5368190d1164f35de5b02cf2
--- /dev/null
+++ b/sandbox/linux/services/namespace_utils.h
@@ -0,0 +1,34 @@
+// Copyright (c) 2014 The Chromium Authors. All rights reserved.

[jln (very slow on Chromium), 2015/01/14 00:46:37]

Not (c) after "Copyright" anymore

[rickyz (no longer on Chrome), 2015/01/23 01:20:19]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SANDBOX_LINUX_SERVICES_NAMESPACE_UTILS_H_
+#define SANDBOX_LINUX_SERVICES_NAMESPACE_UTILS_H_
+
+#include <sys/types.h>
+
+#include "base/macros.h"
+#include "base/template_util.h"
+#include "sandbox/sandbox_export.h"
+

[jln (very slow on Chromium), 2015/01/14 00:46:37]

Please, add a little bit of documentation about what this class is for. (cf
style guide)

[rickyz (no longer on Chrome), 2015/01/23 01:20:19]

Not the best comment, since the class is a little sparse - hope that's OK

+namespace sandbox {
+
+class SANDBOX_EXPORT NamespaceUtils {
+ public:
+  COMPILE_ASSERT((base::is_same<uid_t, gid_t>::value), UidAndGidAreSameType);
+  // generic_id_t can be used for either uid_t or gid_t.
+  typedef uid_t generic_id_t;
+
+  // Write a uid or gid mapping from |id| to |id| in |map_file|.
+  static bool WriteToIdMapFile(const char* map_file, generic_id_t id);
+
+  // Returns true if the namespace type |type| is supported. |type| must be one
+  // of CLONE_NEWIPC, CLONE_NEWNET, CLONE_NEWNS, CLONE_NEWPID, CLONE_NEWUSER, or
+  // CLONE_NEWUTS. This relies on access to /proc, so it will not work from
+  // within a chroot.
+  static bool SupportsLinuxNamespace(int type);
+};

[jln (very slow on Chromium), 2015/01/14 00:46:37]

DISALLOW_IMPLICIT_CONSTRUCTORS

[rickyz (no longer on Chrome), 2015/01/23 01:20:17]

Done.

+
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_SERVICES_NAMESPACE_UTILS_H_