Fix some potential Mach port leaks from mach_host_self using a new ScopedMachPort class.

base/mac/scoped_mach_port.h

+// Copyright (c) 2012 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 BASE_MAC_SCOPED_MACH_PORT_H_
+#define BASE_MAC_SCOPED_MACH_PORT_H_
+
+#include <mach/mach.h>
+
+#include "base/basictypes.h"
+#include "base/base_export.h"
+
+namespace base {
+namespace mac {
+
+// A class for managing the life of a Mach port, releasing via
+// mach_port_deallocate either its send and/or receive rights.
+class BASE_EXPORT ScopedMachPort {
+ public:
+  // Creates a scoper by taking ownership of the port.
+  explicit ScopedMachPort(mach_port_t port);
+
+  ~ScopedMachPort();
+
+  operator mach_port_t() const {
+    return port_;
+  }
+
+  mach_port_t get() const {
+    return port_;
+  }
+
+ private:
+  mach_port_t port_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedMachPort);
+};
+
+}  // namespace mac
+}  // namespace base
+
+#endif  // BASE_MAC_SCOPED_MACH_PORT_H_