xpc-connection

When passed with a config hash-map, returns a parent CrossPageChannel object. Keys in the config hash map are downcased versions of the goog.net.xpc.CfgFields enum keys, e.g. goog.net.xpc.CfgFields.PEER_URI becomes :peer_uri in the config hash. When passed with no args, creates a child CrossPageChannel object, and the config is automatically taken from the URL param 'xpc', as per the CrossPageChannel API.