exports.RTCSessionDescription = RTCSessionDescription || window.mozRTCSessionDescription || window.RTCSessionDescription;
exports.RTCPeerConnection = RTCPeerConnection || window.mozRTCPeerConnection || window.webkitRTCPeerConnection || window.RTCPeerConnection;
exports.RTCIceCandidate = RTCIceCandidate || window.mozRTCIceCandidate || window.RTCIceCandidate;