WebRTC Polyfills

//RTCPeerConnection
window.RTCPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection ||
            window.webkitRTCPeerConnection || window.msRTCPeerConnection;
//getUserMedia
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia ||
                       navigator.mozGetUserMedia || navigator.msGetUserMedia;
//SessionDescription
window.SessionDescription = window.RTCSessionDescription || window.mozRTCSessionDescription ||
                            window.webkitRTCSessionDescription || msSessionDescription;