Clean up media header include guards

media/cast/test/utility/net_utility.h

Index: media/cast/test/utility/net_utility.h
diff --git a/media/cast/test/utility/net_utility.h b/media/cast/test/utility/net_utility.h
index c1199be7a873f9f623c593915585ed13ca684460..9650388348a9d876386952ab33ec78de6758afaf 100644
--- a/media/cast/test/utility/net_utility.h
+++ b/media/cast/test/utility/net_utility.h
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifndef MEDIA_CAST_TEST_UTILITY_NET_UTILITY_H_
+#define MEDIA_CAST_TEST_UTILITY_NET_UTILITY_H_
+
 #include "net/base/ip_endpoint.h"
 
 namespace media {
@@ -16,3 +19,5 @@ net::IPEndPoint GetFreeLocalPort();
 }  // namespace test
 }  // namespace cast
 }  // namespace media
+
+#endif  // MEDIA_CAST_TEST_UTILITY_NET_UTILITY_H_