Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=57490 Make it possible to use Tomcat's WebSocket client within a web application when running under a SecurityManager. Based on a patch by Mikael Sterner.
tomcat/tc8.0.x/trunk/
tomcat/tc8.0.x/trunk/java/org/apache/tomcat/websocket/AsyncChannelGroupUtil.java