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/**
 * Description of import/upgrade into Moodle:
 *
 * 1. Visit https://github.com/webrtc/adapter/releases.
 * 2. Check if the version has been updated from what is listed in lib/thirdpartylibs.xml in the Moodle wwwroot.
 * 3. If it has -
 *    1. Download the source code.
 *    2. Copy the content of the file release/adapter.js from the archive (ignore the first line).
 *    3. Replace the content below "return (function e(t,n,r) .." in this file with the content you copied.
 *    4. Ensure to update lib/thirdpartylibs.xml with any changes.
 */

// ESLint directives.
/* eslint-disable */

// JSHint directives.
/* jshint ignore:start */

define([], function() {
return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
/*
 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree.
 */
 /* eslint-env node */
'use strict';

var SDPUtils = require('sdp');

function writeMediaSection(transceiver, caps, type, stream, dtlsRole) {
    var sdp = SDPUtils.writeRtpDescription(transceiver.kind, caps);

// Map ICE parameters (ufrag, pwd) to SDP.
    sdp += SDPUtils.writeIceParameters(
        transceiver.iceGatherer.getLocalParameters());

// Map DTLS parameters to SDP.
    sdp += SDPUtils.writeDtlsParameters(
        transceiver.dtlsTransport.getLocalParameters(),
        type === 'offer' ? 'actpass' : dtlsRole || 'active');

sdp += 'a=mid:' + transceiver.mid + '\r\n';

if (transceiver.rtpSender && transceiver.rtpReceiver) {
        sdp += 'a=sendrecv\r\n';
    } else if (transceiver.rtpSender) {
        sdp += 'a=sendonly\r\n';
    } else if (transceiver.rtpReceiver) {
        sdp += 'a=recvonly\r\n';
    } else {
        sdp += 'a=inactive\r\n';
    }

if (transceiver.rtpSender) {
        var trackId = transceiver.rtpSender._initialTrackId ||
            transceiver.rtpSender.track.id;
        transceiver.rtpSender._initialTrackId = trackId;
        // spec.
        var msid = 'msid:' + (stream ? stream.id : '-') + ' ' +
            trackId + '\r\n';
        sdp += 'a=' + msid;
        // for Chrome. Legacy should no longer be required.
        sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
            ' ' + msid;

// RTX
        if (transceiver.sendEncodingParameters[0].rtx) {
            sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
                ' ' + msid;
            sdp += 'a=ssrc-group:FID ' +
                transceiver.sendEncodingParameters[0].ssrc + ' ' +
                transceiver.sendEncodingParameters[0].rtx.ssrc +
                '\r\n';
        }
    }
    // FIXME: this should be written by writeRtpDescription.
    sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
        ' cname:' + SDPUtils.localCName + '\r\n';
    if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
        sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
            ' cname:' + SDPUtils.localCName + '\r\n';
    }
    return sdp;
}

// Edge does not like
// 1) stun: filtered after 14393 unless ?transport=udp is present
// 2) turn: that does not have all of turn:host:port?transport=udp
// 3) turn: with ipv6 addresses
// 4) turn: occurring muliple times
function filterIceServers(iceServers, edgeVersion) {
    var hasTurn = false;
    iceServers = JSON.parse(JSON.stringify(iceServers));
    return iceServers.filter(function(server) {
        if (server && (server.urls || server.url)) {
            var urls = server.urls || server.url;
            if (server.url && !server.urls) {
                console.warn('RTCIceServer.url is deprecated! Use urls instead.');
            }
            var isString = typeof urls === 'string';
            if (isString) {
                urls = [urls];
            }
            urls = urls.filter(function(url) {
                var validTurn = url.indexOf('turn:') === 0 &&
                    url.indexOf('transport=udp') !== -1 &&
                    url.indexOf('turn:[') === -1 &&
                    !hasTurn;

if (validTurn) {
                    hasTurn = true;
                    return true;
                }
                return url.indexOf('stun:') === 0 && edgeVersion >= 14393 &&
                    url.indexOf('?transport=udp') === -1;
            });

delete server.url;
            server.urls = isString ? urls[0] : urls;
            return !!urls.length;
        }
    });
}

// Determines the intersection of local and remote capabilities.
function getCommonCapabilities(localCapabilities, remoteCapabilities) {
    var commonCapabilities = {
        codecs: [],
        headerExtensions: [],
        fecMechanisms: []
    };

var rtxCapabilityMatches = function(lRtx, rRtx, lCodecs, rCodecs) {
        var lCodec = findCodecByPayloadType(lRtx.parameters.apt, lCodecs);
        var rCodec = findCodecByPayloadType(rRtx.parameters.apt, rCodecs);
        return lCodec && rCodec &&
            lCodec.name.toLowerCase() === rCodec.name.toLowerCase();
    };

localCapabilities.codecs.forEach(function(lCodec) {
        for (var i = 0; i < remoteCapabilities.codecs.length; i++) {
            var rCodec = remoteCapabilities.codecs[i];
            if (lCodec.name.toLowerCase() === rCodec.name.toLowerCase() &&
                lCodec.clockRate === rCodec.clockRate) {
                if (lCodec.name.toLowerCase() === 'rtx' &&
                    lCodec.parameters && rCodec.parameters.apt) {
                    // for RTX we need to find the local rtx that has a apt
                    // which points to the same local codec as the remote one.
                    if (!rtxCapabilityMatches(lCodec, rCodec,
                        localCapabilities.codecs, remoteCapabilities.codecs)) {
                        continue;
                    }
                }
                rCodec = JSON.parse(JSON.stringify(rCodec)); // deepcopy
                // number of channels is the highest common number of channels
                rCodec.numChannels = Math.min(lCodec.numChannels,
                    rCodec.numChannels);
                // push rCodec so we reply with offerer payload type
                commonCapabilities.codecs.push(rCodec);

// determine common feedback mechanisms
                rCodec.rtcpFeedback = rCodec.rtcpFeedback.filter(function(fb) {
                    for (var j = 0; j < lCodec.rtcpFeedback.length; j++) {
                        if (lCodec.rtcpFeedback[j].type === fb.type &&
                            lCodec.rtcpFeedback[j].parameter === fb.parameter) {
                            return true;
                        }
                    }
                    return false;
                });
                // FIXME: also need to determine .parameters
                //  see https://github.com/openpeer/ortc/issues/569
                break;
            }
        }
    });

localCapabilities.headerExtensions.forEach(function(lHeaderExtension) {
        for (var i = 0; i < remoteCapabilities.headerExtensions.length;
             i++) {
            var rHeaderExtension = remoteCapabilities.headerExtensions[i];
            if (lHeaderExtension.uri === rHeaderExtension.uri) {
                commonCapabilities.headerExtensions.push(rHeaderExtension);
                break;
            }
        }
    });

// FIXME: fecMechanisms
    return commonCapabilities;
}

// is action=setLocalDescription with type allowed in signalingState
function isActionAllowedInSignalingState(action, type, signalingState) {
    return {
        offer: {
            setLocalDescription: ['stable', 'have-local-offer'],
            setRemoteDescription: ['stable', 'have-remote-offer']
        },
        answer: {
            setLocalDescription: ['have-remote-offer', 'have-local-pranswer'],
            setRemoteDescription: ['have-local-offer', 'have-remote-pranswer']
        }
    }[type][action].indexOf(signalingState) !== -1;
}

function makeError(name, description) {
    var e = new Error(description);
    e.name = name;
    // legacy error codes from https://heycam.github.io/webidl/#idl-DOMException-error-names
    e.code = {
        NotSupportedError: 9,
        InvalidStateError: 11,
        InvalidAccessError: 15,
        TypeError: undefined,
        OperationError: undefined
    }[name];
    return e;
}

module.exports = function(window, edgeVersion) {
    // https://w3c.github.io/mediacapture-main/#mediastream
    // Helper function to add the track to the stream and
    // dispatch the event ourselves.
    function addTrackToStreamAndFireEvent(track, stream) {
        stream.addTrack(track);
        stream.dispatchEvent(new window.MediaStreamTrackEvent('addtrack',
            {track: track}));
    }

function removeTrackFromStreamAndFireEvent(track, stream) {
        stream.removeTrack(track);
        stream.dispatchEvent(new window.MediaStreamTrackEvent('removetrack',
            {track: track}));
    }

var RTCPeerConnection = function(config) {
        var pc = this;

var _eventTarget = document.createDocumentFragment();
        ['addEventListener', 'removeEventListener', 'dispatchEvent']
            .forEach(function(method) {
                pc[method] = _eventTarget[method].bind(_eventTarget);
            });

this.canTrickleIceCandidates = null;

this.needNegotiation = false;

this.localStreams = [];
        this.remoteStreams = [];

this.localDescription = null;
        this.remoteDescription = null;

this.signalingState = 'stable';
        this.iceConnectionState = 'new';
        this.connectionState = 'new';
        this.iceGatheringState = 'new';

config = JSON.parse(JSON.stringify(config || {}));

this.usingBundle = config.bundlePolicy === 'max-bundle';
        if (config.rtcpMuxPolicy === 'negotiate') {
            throw(makeError('NotSupportedError',
                'rtcpMuxPolicy \'negotiate\' is not supported'));
        } else if (!config.rtcpMuxPolicy) {
            config.rtcpMuxPolicy = 'require';
        }

switch (config.iceTransportPolicy) {
            case 'all':
            case 'relay':
                break;
            default:
                config.iceTransportPolicy = 'all';
                break;
        }

switch (config.bundlePolicy) {
            case 'balanced':
            case 'max-compat':
            case 'max-bundle':
                break;
            default:
                config.bundlePolicy = 'balanced';
                break;
        }

config.iceServers = filterIceServers(config.iceServers || [], edgeVersion);

this._iceGatherers = [];
        if (config.iceCandidatePoolSize) {
            for (var i = config.iceCandidatePoolSize; i > 0; i--) {
                this._iceGatherers.push(new window.RTCIceGatherer({
                    iceServers: config.iceServers,
                    gatherPolicy: config.iceTransportPolicy
                }));
            }
        } else {
            config.iceCandidatePoolSize = 0;
        }

this._config = config;

// per-track iceGathers, iceTransports, dtlsTransports, rtpSenders, ...
        // everything that is needed to describe a SDP m-line.
        this.transceivers = [];

this._sdpSessionId = SDPUtils.generateSessionId();
        this._sdpSessionVersion = 0;

this._dtlsRole = undefined; // role for a=setup to use in answers.

this._isClosed = false;
    };

// set up event handlers on prototype
    RTCPeerConnection.prototype.onicecandidate = null;
    RTCPeerConnection.prototype.onaddstream = null;
    RTCPeerConnection.prototype.ontrack = null;
    RTCPeerConnection.prototype.onremovestream = null;
    RTCPeerConnection.prototype.onsignalingstatechange = null;
    RTCPeerConnection.prototype.oniceconnectionstatechange = null;
    RTCPeerConnection.prototype.onconnectionstatechange = null;
    RTCPeerConnection.prototype.onicegatheringstatechange = null;
    RTCPeerConnection.prototype.onnegotiationneeded = null;
    RTCPeerConnection.prototype.ondatachannel = null;

RTCPeerConnection.prototype._dispatchEvent = function(name, event) {
        if (this._isClosed) {
            return;
        }
        this.dispatchEvent(event);
        if (typeof this['on' + name] === 'function') {
            this['on' + name](event);
        }
    };

RTCPeerConnection.prototype._emitGatheringStateChange = function() {
        var event = new Event('icegatheringstatechange');
        this._dispatchEvent('icegatheringstatechange', event);
    };

RTCPeerConnection.prototype.getConfiguration = function() {
        return this._config;
    };

RTCPeerConnection.prototype.getLocalStreams = function() {
        return this.localStreams;
    };

RTCPeerConnection.prototype.getRemoteStreams = function() {
        return this.remoteStreams;
    };

// internal helper to create a transceiver object.
    // (which is not yet the same as the WebRTC 1.0 transceiver)
    RTCPeerConnection.prototype._createTransceiver = function(kind, doNotAdd) {
        var hasBundleTransport = this.transceivers.length > 0;
        var transceiver = {
            track: null,
            iceGatherer: null,
            iceTransport: null,
            dtlsTransport: null,
            localCapabilities: null,
            remoteCapabilities: null,
            rtpSender: null,
            rtpReceiver: null,
            kind: kind,
            mid: null,
            sendEncodingParameters: null,
            recvEncodingParameters: null,
            stream: null,
            associatedRemoteMediaStreams: [],
            wantReceive: true
        };
        if (this.usingBundle && hasBundleTransport) {
            transceiver.iceTransport = this.transceivers[0].iceTransport;
            transceiver.dtlsTransport = this.transceivers[0].dtlsTransport;
        } else {
            var transports = this._createIceAndDtlsTransports();
            transceiver.iceTransport = transports.iceTransport;
            transceiver.dtlsTransport = transports.dtlsTransport;
        }
        if (!doNotAdd) {
            this.transceivers.push(transceiver);
        }
        return transceiver;
    };

RTCPeerConnection.prototype.addTrack = function(track, stream) {
        if (this._isClosed) {
            throw makeError('InvalidStateError',
                'Attempted to call addTrack on a closed peerconnection.');
        }

var alreadyExists = this.transceivers.find(function(s) {
            return s.track === track;
        });

if (alreadyExists) {
            throw makeError('InvalidAccessError', 'Track already exists.');
        }

var transceiver;
        for (var i = 0; i < this.transceivers.length; i++) {
            if (!this.transceivers[i].track &&
                this.transceivers[i].kind === track.kind) {
                transceiver = this.transceivers[i];
            }
        }
        if (!transceiver) {
            transceiver = this._createTransceiver(track.kind);
        }

this._maybeFireNegotiationNeeded();

if (this.localStreams.indexOf(stream) === -1) {
            this.localStreams.push(stream);
        }

transceiver.track = track;
        transceiver.stream = stream;
        transceiver.rtpSender = new window.RTCRtpSender(track,
            transceiver.dtlsTransport);
        return transceiver.rtpSender;
    };

RTCPeerConnection.prototype.addStream = function(stream) {
        var pc = this;
        if (edgeVersion >= 15025) {
            stream.getTracks().forEach(function(track) {
                pc.addTrack(track, stream);
            });
        } else {
            // Clone is necessary for local demos mostly, attaching directly
            // to two different senders does not work (build 10547).
            // Fixed in 15025 (or earlier)
            var clonedStream = stream.clone();
            stream.getTracks().forEach(function(track, idx) {
                var clonedTrack = clonedStream.getTracks()[idx];
                track.addEventListener('enabled', function(event) {
                    clonedTrack.enabled = event.enabled;
                });
            });
            clonedStream.getTracks().forEach(function(track) {
                pc.addTrack(track, clonedStream);
            });
        }
    };

RTCPeerConnection.prototype.removeTrack = function(sender) {
        if (this._isClosed) {
            throw makeError('InvalidStateError',
                'Attempted to call removeTrack on a closed peerconnection.');
        }

if (!(sender instanceof window.RTCRtpSender)) {
            throw new TypeError('Argument 1 of RTCPeerConnection.removeTrack ' +
                'does not implement interface RTCRtpSender.');
        }

var transceiver = this.transceivers.find(function(t) {
            return t.rtpSender === sender;
        });

if (!transceiver) {
            throw makeError('InvalidAccessError',
                'Sender was not created by this connection.');
        }
        var stream = transceiver.stream;

transceiver.rtpSender.stop();
        transceiver.rtpSender = null;
        transceiver.track = null;
        transceiver.stream = null;

// remove the stream from the set of local streams
        var localStreams = this.transceivers.map(function(t) {
            return t.stream;
        });
        if (localStreams.indexOf(stream) === -1 &&
            this.localStreams.indexOf(stream) > -1) {
            this.localStreams.splice(this.localStreams.indexOf(stream), 1);
        }

this._maybeFireNegotiationNeeded();
    };

RTCPeerConnection.prototype.removeStream = function(stream) {
        var pc = this;
        stream.getTracks().forEach(function(track) {
            var sender = pc.getSenders().find(function(s) {
                return s.track === track;
            });
            if (sender) {
                pc.removeTrack(sender);
            }
        });
    };

RTCPeerConnection.prototype.getSenders = function() {
        return this.transceivers.filter(function(transceiver) {
            return !!transceiver.rtpSender;
        })
            .map(function(transceiver) {
                return transceiver.rtpSender;
            });
    };

RTCPeerConnection.prototype.getReceivers = function() {
        return this.transceivers.filter(function(transceiver) {
            return !!transceiver.rtpReceiver;
        })
            .map(function(transceiver) {
                return transceiver.rtpReceiver;
            });
    };

RTCPeerConnection.prototype._createIceGatherer = function(sdpMLineIndex,
                                                              usingBundle) {
        var pc = this;
        if (usingBundle && sdpMLineIndex > 0) {
            return this.transceivers[0].iceGatherer;
        } else if (this._iceGatherers.length) {
            return this._iceGatherers.shift();
        }
        var iceGatherer = new window.RTCIceGatherer({
            iceServers: this._config.iceServers,
            gatherPolicy: this._config.iceTransportPolicy
        });
        Object.defineProperty(iceGatherer, 'state',
            {value: 'new', writable: true}
        );

this.transceivers[sdpMLineIndex].bufferedCandidateEvents = [];
        this.transceivers[sdpMLineIndex].bufferCandidates = function(event) {
            var end = !event.candidate || Object.keys(event.candidate).length === 0;
            // polyfill since RTCIceGatherer.state is not implemented in
            // Edge 10547 yet.
            iceGatherer.state = end ? 'completed' : 'gathering';
            if (pc.transceivers[sdpMLineIndex].bufferedCandidateEvents !== null) {
                pc.transceivers[sdpMLineIndex].bufferedCandidateEvents.push(event);
            }
        };
        iceGatherer.addEventListener('localcandidate',
            this.transceivers[sdpMLineIndex].bufferCandidates);
        return iceGatherer;
    };

// start gathering from an RTCIceGatherer.
    RTCPeerConnection.prototype._gather = function(mid, sdpMLineIndex) {
        var pc = this;
        var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer;
        if (iceGatherer.onlocalcandidate) {
            return;
        }
        var bufferedCandidateEvents =
            this.transceivers[sdpMLineIndex].bufferedCandidateEvents;
        this.transceivers[sdpMLineIndex].bufferedCandidateEvents = null;
        iceGatherer.removeEventListener('localcandidate',
            this.transceivers[sdpMLineIndex].bufferCandidates);
        iceGatherer.onlocalcandidate = function(evt) {
            if (pc.usingBundle && sdpMLineIndex > 0) {
                // if we know that we use bundle we can drop candidates with
                // Ñ•dpMLineIndex > 0. If we don't do this then our state gets
                // confused since we dispose the extra ice gatherer.
                return;
            }
            var event = new Event('icecandidate');
            event.candidate = {sdpMid: mid, sdpMLineIndex: sdpMLineIndex};

var serializedCandidate = SDPUtils.writeCandidate(cand);
                event.candidate = Object.assign(event.candidate,
                    SDPUtils.parseCandidate(serializedCandidate));

event.candidate.candidate = serializedCandidate;
                event.candidate.toJSON = function() {
                    return {
                        candidate: event.candidate.candidate,
                        sdpMid: event.candidate.sdpMid,
                        sdpMLineIndex: event.candidate.sdpMLineIndex,
                        usernameFragment: event.candidate.usernameFragment
                    };
                };
            }

// update local description.
            var sections = SDPUtils.getMediaSections(pc.localDescription.sdp);
            if (!end) {
                sections[event.candidate.sdpMLineIndex] +=
                    'a=' + event.candidate.candidate + '\r\n';
            } else {
                sections[event.candidate.sdpMLineIndex] +=
                    'a=end-of-candidates\r\n';
            }
            pc.localDescription.sdp =
                SDPUtils.getDescription(pc.localDescription.sdp) +
                sections.join('');
            var complete = pc.transceivers.every(function(transceiver) {
                return transceiver.iceGatherer &&
                    transceiver.iceGatherer.state === 'completed';
            });

if (pc.iceGatheringState !== 'gathering') {
                pc.iceGatheringState = 'gathering';
                pc._emitGatheringStateChange();
            }

// Emit candidate. Also emit null candidate when all gatherers are
            // complete.
            if (!end) {
                pc._dispatchEvent('icecandidate', event);
            }
            if (complete) {
                pc._dispatchEvent('icecandidate', new Event('icecandidate'));
                pc.iceGatheringState = 'complete';
                pc._emitGatheringStateChange();
            }
        };

// emit already gathered candidates.
        window.setTimeout(function() {
            bufferedCandidateEvents.forEach(function(e) {
                iceGatherer.onlocalcandidate(e);
            });
        }, 0);
    };

// Create ICE transport and DTLS transport.
    RTCPeerConnection.prototype._createIceAndDtlsTransports = function() {
        var pc = this;
        var iceTransport = new window.RTCIceTransport(null);
        iceTransport.onicestatechange = function() {
            pc._updateIceConnectionState();
            pc._updateConnectionState();
        };

return {
            iceTransport: iceTransport,
            dtlsTransport: dtlsTransport
        };
    };

// Destroy ICE gatherer, ICE transport and DTLS transport.
    // Without triggering the callbacks.
    RTCPeerConnection.prototype._disposeIceAndDtlsTransports = function(
        sdpMLineIndex) {
        var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer;
        if (iceGatherer) {
            delete iceGatherer.onlocalcandidate;
            delete this.transceivers[sdpMLineIndex].iceGatherer;
        }
        var iceTransport = this.transceivers[sdpMLineIndex].iceTransport;
        if (iceTransport) {
            delete iceTransport.onicestatechange;
            delete this.transceivers[sdpMLineIndex].iceTransport;
        }
        var dtlsTransport = this.transceivers[sdpMLineIndex].dtlsTransport;
        if (dtlsTransport) {
            delete dtlsTransport.ondtlsstatechange;
            delete dtlsTransport.onerror;
            delete this.transceivers[sdpMLineIndex].dtlsTransport;
        }
    };

// Start the RTP Sender and Receiver for a transceiver.
    RTCPeerConnection.prototype._transceive = function(transceiver,
                                                       send, recv) {
        var params = getCommonCapabilities(transceiver.localCapabilities,
            transceiver.remoteCapabilities);
        if (send && transceiver.rtpSender) {
            params.encodings = transceiver.sendEncodingParameters;
            params.rtcp = {
                cname: SDPUtils.localCName,
                compound: transceiver.rtcpParameters.compound
            };
            if (transceiver.recvEncodingParameters.length) {
                params.rtcp.ssrc = transceiver.recvEncodingParameters[0].ssrc;
            }
            transceiver.rtpSender.send(params);
        }
        if (recv && transceiver.rtpReceiver && params.codecs.length > 0) {
            // remove RTX field in Edge 14942
            if (transceiver.kind === 'video'
                && transceiver.recvEncodingParameters
                && edgeVersion < 15019) {
                transceiver.recvEncodingParameters.forEach(function(p) {
                    delete p.rtx;
                });
            }
            if (transceiver.recvEncodingParameters.length) {
                params.encodings = transceiver.recvEncodingParameters;
            } else {
                params.encodings = [{}];
            }
            params.rtcp = {
                compound: transceiver.rtcpParameters.compound
            };
            if (transceiver.rtcpParameters.cname) {
                params.rtcp.cname = transceiver.rtcpParameters.cname;
            }
            if (transceiver.sendEncodingParameters.length) {
                params.rtcp.ssrc = transceiver.sendEncodingParameters[0].ssrc;
            }
            transceiver.rtpReceiver.receive(params);
        }
    };

RTCPeerConnection.prototype.setLocalDescription = function(description) {
        var pc = this;

// Note: pranswer is not supported.
        if (['offer', 'answer'].indexOf(description.type) === -1) {
            return Promise.reject(makeError('TypeError',
                'Unsupported type "' + description.type + '"'));
        }

if (!isActionAllowedInSignalingState('setLocalDescription',
            description.type, pc.signalingState) || pc._isClosed) {
            return Promise.reject(makeError('InvalidStateError',
                'Can not set local ' + description.type +
                ' in state ' + pc.signalingState));
        }

var sections;
        var sessionpart;
        if (description.type === 'offer') {
            // VERY limited support for SDP munging. Limited to:
            // * changing the order of codecs
            sections = SDPUtils.splitSections(description.sdp);
            sessionpart = sections.shift();
            sections.forEach(function(mediaSection, sdpMLineIndex) {
                var caps = SDPUtils.parseRtpParameters(mediaSection);
                pc.transceivers[sdpMLineIndex].localCapabilities = caps;
            });

pc.transceivers.forEach(function(transceiver, sdpMLineIndex) {
                pc._gather(transceiver.mid, sdpMLineIndex);
            });
        } else if (description.type === 'answer') {
            sections = SDPUtils.splitSections(pc.remoteDescription.sdp);
            sessionpart = sections.shift();
            var isIceLite = SDPUtils.matchPrefix(sessionpart,
                'a=ice-lite').length > 0;
            sections.forEach(function(mediaSection, sdpMLineIndex) {
                var transceiver = pc.transceivers[sdpMLineIndex];
                var iceGatherer = transceiver.iceGatherer;
                var iceTransport = transceiver.iceTransport;
                var dtlsTransport = transceiver.dtlsTransport;
                var localCapabilities = transceiver.localCapabilities;
                var remoteCapabilities = transceiver.remoteCapabilities;

// treat bundle-only as not-rejected.
                var rejected = SDPUtils.isRejected(mediaSection) &&
                    SDPUtils.matchPrefix(mediaSection, 'a=bundle-only').length === 0;

if (!rejected && !transceiver.rejected) {
                    var remoteIceParameters = SDPUtils.getIceParameters(
                        mediaSection, sessionpart);
                    var remoteDtlsParameters = SDPUtils.getDtlsParameters(
                        mediaSection, sessionpart);
                    if (isIceLite) {
                        remoteDtlsParameters.role = 'server';
                    }

if (!pc.usingBundle || sdpMLineIndex === 0) {
                        pc._gather(transceiver.mid, sdpMLineIndex);
                        if (iceTransport.state === 'new') {
                            iceTransport.start(iceGatherer, remoteIceParameters,
                                isIceLite ? 'controlling' : 'controlled');
                        }
                        if (dtlsTransport.state === 'new') {
                            dtlsTransport.start(remoteDtlsParameters);
                        }
                    }

// Calculate intersection of capabilities.
                    var params = getCommonCapabilities(localCapabilities,
                        remoteCapabilities);

// Start the RTCRtpSender. The RTCRtpReceiver for this
                    // transceiver has already been started in setRemoteDescription.
                    pc._transceive(transceiver,
                        params.codecs.length > 0,
                        false);
                }
            });
        }

pc.localDescription = {
            type: description.type,
            sdp: description.sdp
        };
        if (description.type === 'offer') {
            pc._updateSignalingState('have-local-offer');
        } else {
            pc._updateSignalingState('stable');
        }

return Promise.resolve();
    };

RTCPeerConnection.prototype.setRemoteDescription = function(description) {
        var pc = this;

if (!isActionAllowedInSignalingState('setRemoteDescription',
            description.type, pc.signalingState) || pc._isClosed) {
            return Promise.reject(makeError('InvalidStateError',
                'Can not set remote ' + description.type +
                ' in state ' + pc.signalingState));
        }

sections.forEach(function(mediaSection, sdpMLineIndex) {
            var lines = SDPUtils.splitLines(mediaSection);
            var kind = SDPUtils.getKind(mediaSection);
            // treat bundle-only as not-rejected.
            var rejected = SDPUtils.isRejected(mediaSection) &&
                SDPUtils.matchPrefix(mediaSection, 'a=bundle-only').length === 0;
            var protocol = lines[0].substr(2).split(' ')[2];

var direction = SDPUtils.getDirection(mediaSection, sessionpart);
            var remoteMsid = SDPUtils.parseMsid(mediaSection);

var mid = SDPUtils.getMid(mediaSection) || SDPUtils.generateIdentifier();

// Reject datachannels which are not implemented yet.
            if ((kind === 'application' && protocol === 'DTLS/SCTP') || rejected) {
                // TODO: this is dangerous in the case where a non-rejected m-line
                //     becomes rejected.
                pc.transceivers[sdpMLineIndex] = {
                    mid: mid,
                    kind: kind,
                    rejected: true
                };
                return;
            }

if (!rejected && pc.transceivers[sdpMLineIndex] &&
                pc.transceivers[sdpMLineIndex].rejected) {
                // recycle a rejected transceiver.
                pc.transceivers[sdpMLineIndex] = pc._createTransceiver(kind, true);
            }

var transceiver;
            var iceGatherer;
            var iceTransport;
            var dtlsTransport;
            var rtpReceiver;
            var sendEncodingParameters;
            var recvEncodingParameters;
            var localCapabilities;

var track;
            // FIXME: ensure the mediaSection has rtcp-mux set.
            var remoteCapabilities = SDPUtils.parseRtpParameters(mediaSection);
            var remoteIceParameters;
            var remoteDtlsParameters;
            if (!rejected) {
                remoteIceParameters = SDPUtils.getIceParameters(mediaSection,
                    sessionpart);
                remoteDtlsParameters = SDPUtils.getDtlsParameters(mediaSection,
                    sessionpart);
                remoteDtlsParameters.role = 'client';
            }
            recvEncodingParameters =
                SDPUtils.parseRtpEncodingParameters(mediaSection);

var rtcpParameters = SDPUtils.parseRtcpParameters(mediaSection);

var isComplete = SDPUtils.matchPrefix(mediaSection,
                'a=end-of-candidates', sessionpart).length > 0;
            var cands = SDPUtils.matchPrefix(mediaSection, 'a=candidate:')
                .map(function(cand) {
                    return SDPUtils.parseCandidate(cand);
                })
                .filter(function(cand) {
                    return cand.component === 1;
                });

// Check if we can use BUNDLE and dispose transports.
            if ((description.type === 'offer' || description.type === 'answer') &&
                !rejected && usingBundle && sdpMLineIndex > 0 &&
                pc.transceivers[sdpMLineIndex]) {
                pc._disposeIceAndDtlsTransports(sdpMLineIndex);
                pc.transceivers[sdpMLineIndex].iceGatherer =
                    pc.transceivers[0].iceGatherer;
                pc.transceivers[sdpMLineIndex].iceTransport =
                    pc.transceivers[0].iceTransport;
                pc.transceivers[sdpMLineIndex].dtlsTransport =
                    pc.transceivers[0].dtlsTransport;
                if (pc.transceivers[sdpMLineIndex].rtpSender) {
                    pc.transceivers[sdpMLineIndex].rtpSender.setTransport(
                        pc.transceivers[0].dtlsTransport);
                }
                if (pc.transceivers[sdpMLineIndex].rtpReceiver) {
                    pc.transceivers[sdpMLineIndex].rtpReceiver.setTransport(
                        pc.transceivers[0].dtlsTransport);
                }
            }
            if (description.type === 'offer' && !rejected) {
                transceiver = pc.transceivers[sdpMLineIndex] ||
                    pc._createTransceiver(kind);
                transceiver.mid = mid;

if (!transceiver.iceGatherer) {
                    transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex,
                        usingBundle);
                }

if (cands.length && transceiver.iceTransport.state === 'new') {
                    if (isComplete && (!usingBundle || sdpMLineIndex === 0)) {
                        transceiver.iceTransport.setRemoteCandidates(cands);
                    } else {
                        cands.forEach(function(candidate) {
                            maybeAddCandidate(transceiver.iceTransport, candidate);
                        });
                    }
                }

localCapabilities = window.RTCRtpReceiver.getCapabilities(kind);

// filter RTX until additional stuff needed for RTX is implemented
                // in adapter.js
                if (edgeVersion < 15019) {
                    localCapabilities.codecs = localCapabilities.codecs.filter(
                        function(codec) {
                            return codec.name !== 'rtx';
                        });
                }

sendEncodingParameters = transceiver.sendEncodingParameters || [{
                    ssrc: (2 * sdpMLineIndex + 2) * 1001
                }];

// TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
                var isNewTrack = false;
                if (direction === 'sendrecv' || direction === 'sendonly') {
                    isNewTrack = !transceiver.rtpReceiver;
                    rtpReceiver = transceiver.rtpReceiver ||
                        new window.RTCRtpReceiver(transceiver.dtlsTransport, kind);

if (isNewTrack) {
                        var stream;
                        track = rtpReceiver.track;
                        // FIXME: does not work with Plan B.
                        if (remoteMsid && remoteMsid.stream === '-') {
                            // no-op. a stream id of '-' means: no associated stream.
                        } else if (remoteMsid) {
                            if (!streams[remoteMsid.stream]) {
                                streams[remoteMsid.stream] = new window.MediaStream();
                                Object.defineProperty(streams[remoteMsid.stream], 'id', {
                                    get: function() {
                                        return remoteMsid.stream;
                                    }
                                });
                            }
                            Object.defineProperty(track, 'id', {
                                get: function() {
                                    return remoteMsid.track;
                                }
                            });
                            stream = streams[remoteMsid.stream];
                        } else {
                            if (!streams.default) {
                                streams.default = new window.MediaStream();
                            }
                            stream = streams.default;
                        }
                        if (stream) {
                            addTrackToStreamAndFireEvent(track, stream);
                            transceiver.associatedRemoteMediaStreams.push(stream);
                        }
                        receiverList.push([track, rtpReceiver, stream]);
                    }
                } else if (transceiver.rtpReceiver && transceiver.rtpReceiver.track) {
                    transceiver.associatedRemoteMediaStreams.forEach(function(s) {
                        var nativeTrack = s.getTracks().find(function(t) {
                            return t.id === transceiver.rtpReceiver.track.id;
                        });
                        if (nativeTrack) {
                            removeTrackFromStreamAndFireEvent(nativeTrack, s);
                        }
                    });
                    transceiver.associatedRemoteMediaStreams = [];
                }

transceiver.localCapabilities = localCapabilities;
                transceiver.remoteCapabilities = remoteCapabilities;
                transceiver.rtpReceiver = rtpReceiver;
                transceiver.rtcpParameters = rtcpParameters;
                transceiver.sendEncodingParameters = sendEncodingParameters;
                transceiver.recvEncodingParameters = recvEncodingParameters;

// Start the RTCRtpReceiver now. The RTPSender is started in
                // setLocalDescription.
                pc._transceive(pc.transceivers[sdpMLineIndex],
                    false,
                    isNewTrack);
            } else if (description.type === 'answer' && !rejected) {
                transceiver = pc.transceivers[sdpMLineIndex];
                iceGatherer = transceiver.iceGatherer;
                iceTransport = transceiver.iceTransport;
                dtlsTransport = transceiver.dtlsTransport;
                rtpReceiver = transceiver.rtpReceiver;
                sendEncodingParameters = transceiver.sendEncodingParameters;
                localCapabilities = transceiver.localCapabilities;

pc.transceivers[sdpMLineIndex].recvEncodingParameters =
                    recvEncodingParameters;
                pc.transceivers[sdpMLineIndex].remoteCapabilities =
                    remoteCapabilities;
                pc.transceivers[sdpMLineIndex].rtcpParameters = rtcpParameters;

if (cands.length && iceTransport.state === 'new') {
                    if ((isIceLite || isComplete) &&
                        (!usingBundle || sdpMLineIndex === 0)) {
                        iceTransport.setRemoteCandidates(cands);
                    } else {
                        cands.forEach(function(candidate) {
                            maybeAddCandidate(transceiver.iceTransport, candidate);
                        });
                    }
                }

if (!usingBundle || sdpMLineIndex === 0) {
                    if (iceTransport.state === 'new') {
                        iceTransport.start(iceGatherer, remoteIceParameters,
                            'controlling');
                    }
                    if (dtlsTransport.state === 'new') {
                        dtlsTransport.start(remoteDtlsParameters);
                    }
                }

pc._transceive(transceiver,
                    direction === 'sendrecv' || direction === 'recvonly',
                    direction === 'sendrecv' || direction === 'sendonly');

// TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
                if (rtpReceiver &&
                    (direction === 'sendrecv' || direction === 'sendonly')) {
                    track = rtpReceiver.track;
                    if (remoteMsid) {
                        if (!streams[remoteMsid.stream]) {
                            streams[remoteMsid.stream] = new window.MediaStream();
                        }
                        addTrackToStreamAndFireEvent(track, streams[remoteMsid.stream]);
                        receiverList.push([track, rtpReceiver, streams[remoteMsid.stream]]);
                    } else {
                        if (!streams.default) {
                            streams.default = new window.MediaStream();
                        }
                        addTrackToStreamAndFireEvent(track, streams.default);
                        receiverList.push([track, rtpReceiver, streams.default]);
                    }
                } else {
                    // FIXME: actually the receiver should be created later.
                    delete transceiver.rtpReceiver;
                }
            }
        });

if (pc._dtlsRole === undefined) {
            pc._dtlsRole = description.type === 'offer' ? 'active' : 'passive';
        }

pc.remoteDescription = {
            type: description.type,
            sdp: description.sdp
        };
        if (description.type === 'offer') {
            pc._updateSignalingState('have-remote-offer');
        } else {
            pc._updateSignalingState('stable');
        }
        Object.keys(streams).forEach(function(sid) {
            var stream = streams[sid];
            if (stream.getTracks().length) {
                if (pc.remoteStreams.indexOf(stream) === -1) {
                    pc.remoteStreams.push(stream);
                    var event = new Event('addstream');
                    event.stream = stream;
                    window.setTimeout(function() {
                        pc._dispatchEvent('addstream', event);
                    });
                }

receiverList.forEach(function(item) {
                    var track = item[0];
                    var receiver = item[1];
                    if (stream.id !== item[2].id) {
                        return;
                    }
                    fireAddTrack(pc, track, receiver, [stream]);
                });
            }
        });
        receiverList.forEach(function(item) {
            if (item[2]) {
                return;
            }
            fireAddTrack(pc, item[0], item[1], []);
        });

// check whether addIceCandidate({}) was called within four seconds after
        // setRemoteDescription.
        window.setTimeout(function() {
            if (!(pc && pc.transceivers)) {
                return;
            }
            pc.transceivers.forEach(function(transceiver) {
                if (transceiver.iceTransport &&
                    transceiver.iceTransport.state === 'new' &&
                    transceiver.iceTransport.getRemoteCandidates().length > 0) {
                    console.warn('Timeout for addRemoteCandidate. Consider sending ' +
                        'an end-of-candidates notification');
                    transceiver.iceTransport.addRemoteCandidate({});
                }
            });
        }, 4000);

return Promise.resolve();
    };

RTCPeerConnection.prototype.close = function() {
        this.transceivers.forEach(function(transceiver) {
            /* not yet
if (transceiver.iceGatherer) {
transceiver.iceGatherer.close();
}
*/
            if (transceiver.iceTransport) {
                transceiver.iceTransport.stop();
            }
            if (transceiver.dtlsTransport) {
                transceiver.dtlsTransport.stop();
            }
            if (transceiver.rtpSender) {
                transceiver.rtpSender.stop();
            }
            if (transceiver.rtpReceiver) {
                transceiver.rtpReceiver.stop();
            }
        });
        // FIXME: clean up tracks, local streams, remote streams, etc
        this._isClosed = true;
        this._updateSignalingState('closed');
    };

// Update the signaling state.
    RTCPeerConnection.prototype._updateSignalingState = function(newState) {
        this.signalingState = newState;
        var event = new Event('signalingstatechange');
        this._dispatchEvent('signalingstatechange', event);
    };

// Determine whether to fire the negotiationneeded event.
    RTCPeerConnection.prototype._maybeFireNegotiationNeeded = function() {
        var pc = this;
        if (this.signalingState !== 'stable' || this.needNegotiation === true) {
            return;
        }
        this.needNegotiation = true;
        window.setTimeout(function() {
            if (pc.needNegotiation) {
                pc.needNegotiation = false;
                var event = new Event('negotiationneeded');
                pc._dispatchEvent('negotiationneeded', event);
            }
        }, 0);
    };

// Update the ice connection state.
    RTCPeerConnection.prototype._updateIceConnectionState = function() {
        var newState;
        var states = {
            'new': 0,
            closed: 0,
            checking: 0,
            connected: 0,
            completed: 0,
            disconnected: 0,
            failed: 0
        };
        this.transceivers.forEach(function(transceiver) {
            states[transceiver.iceTransport.state]++;
        });

newState = 'new';
        if (states.failed > 0) {
            newState = 'failed';
        } else if (states.checking > 0) {
            newState = 'checking';
        } else if (states.disconnected > 0) {
            newState = 'disconnected';
        } else if (states.new > 0) {
            newState = 'new';
        } else if (states.connected > 0) {
            newState = 'connected';
        } else if (states.completed > 0) {
            newState = 'completed';
        }

if (newState !== this.iceConnectionState) {
            this.iceConnectionState = newState;
            var event = new Event('iceconnectionstatechange');
            this._dispatchEvent('iceconnectionstatechange', event);
        }
    };

// Update the connection state.
    RTCPeerConnection.prototype._updateConnectionState = function() {
        var newState;
        var states = {
            'new': 0,
            closed: 0,
            connecting: 0,
            connected: 0,
            completed: 0,
            disconnected: 0,
            failed: 0
        };
        this.transceivers.forEach(function(transceiver) {
            states[transceiver.iceTransport.state]++;
            states[transceiver.dtlsTransport.state]++;
        });
        // ICETransport.completed and connected are the same for this purpose.
        states.connected += states.completed;

newState = 'new';
        if (states.failed > 0) {
            newState = 'failed';
        } else if (states.connecting > 0) {
            newState = 'connecting';
        } else if (states.disconnected > 0) {
            newState = 'disconnected';
        } else if (states.new > 0) {
            newState = 'new';
        } else if (states.connected > 0) {
            newState = 'connected';
        }

if (newState !== this.connectionState) {
            this.connectionState = newState;
            var event = new Event('connectionstatechange');
            this._dispatchEvent('connectionstatechange', event);
        }
    };

RTCPeerConnection.prototype.createOffer = function() {
        var pc = this;

if (pc._isClosed) {
            return Promise.reject(makeError('InvalidStateError',
                'Can not call createOffer after close'));
        }

var numAudioTracks = pc.transceivers.filter(function(t) {
            return t.kind === 'audio';
        }).length;
        var numVideoTracks = pc.transceivers.filter(function(t) {
            return t.kind === 'video';
        }).length;

// Determine number of audio and video tracks we need to send/recv.
        var offerOptions = arguments[0];
        if (offerOptions) {
            // Reject Chrome legacy constraints.
            if (offerOptions.mandatory || offerOptions.optional) {
                throw new TypeError(
                    'Legacy mandatory/optional constraints not supported.');
            }
            if (offerOptions.offerToReceiveAudio !== undefined) {
                if (offerOptions.offerToReceiveAudio === true) {
                    numAudioTracks = 1;
                } else if (offerOptions.offerToReceiveAudio === false) {
                    numAudioTracks = 0;
                } else {
                    numAudioTracks = offerOptions.offerToReceiveAudio;
                }
            }
            if (offerOptions.offerToReceiveVideo !== undefined) {
                if (offerOptions.offerToReceiveVideo === true) {
                    numVideoTracks = 1;
                } else if (offerOptions.offerToReceiveVideo === false) {
                    numVideoTracks = 0;
                } else {
                    numVideoTracks = offerOptions.offerToReceiveVideo;
                }
            }
        }

pc.transceivers.forEach(function(transceiver) {
            if (transceiver.kind === 'audio') {
                numAudioTracks--;
                if (numAudioTracks < 0) {
                    transceiver.wantReceive = false;
                }
            } else if (transceiver.kind === 'video') {
                numVideoTracks--;
                if (numVideoTracks < 0) {
                    transceiver.wantReceive = false;
                }
            }
        });

// Create M-lines for recvonly streams.
        while (numAudioTracks > 0 || numVideoTracks > 0) {
            if (numAudioTracks > 0) {
                pc._createTransceiver('audio');
                numAudioTracks--;
            }
            if (numVideoTracks > 0) {
                pc._createTransceiver('video');
                numVideoTracks--;
            }
        }

var sdp = SDPUtils.writeSessionBoilerplate(pc._sdpSessionId,
            pc._sdpSessionVersion++);
        pc.transceivers.forEach(function(transceiver, sdpMLineIndex) {
            // For each track, create an ice gatherer, ice transport,
            // dtls transport, potentially rtpsender and rtpreceiver.
            var track = transceiver.track;
            var kind = transceiver.kind;
            var mid = transceiver.mid || SDPUtils.generateIdentifier();
            transceiver.mid = mid;

if (!transceiver.iceGatherer) {
                transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex,
                    pc.usingBundle);
            }

// for subsequent offers, we might have to re-use the payload
                // type of the last offer.
                if (transceiver.remoteCapabilities &&
                    transceiver.remoteCapabilities.codecs) {
                    transceiver.remoteCapabilities.codecs.forEach(function(remoteCodec) {
                        if (codec.name.toLowerCase() === remoteCodec.name.toLowerCase() &&
                            codec.clockRate === remoteCodec.clockRate) {
                            codec.preferredPayloadType = remoteCodec.payloadType;
                        }
                    });
                }
            });
            localCapabilities.headerExtensions.forEach(function(hdrExt) {
                var remoteExtensions = transceiver.remoteCapabilities &&
                    transceiver.remoteCapabilities.headerExtensions || [];
                remoteExtensions.forEach(function(rHdrExt) {
                    if (hdrExt.uri === rHdrExt.uri) {
                        hdrExt.id = rHdrExt.id;
                    }
                });
            });

// generate an ssrc now, to be used later in rtpSender.send
            var sendEncodingParameters = transceiver.sendEncodingParameters || [{
                ssrc: (2 * sdpMLineIndex + 1) * 1001
            }];
            if (track) {
                // add RTX
                if (edgeVersion >= 15019 && kind === 'video' &&
                    !sendEncodingParameters[0].rtx) {
                    sendEncodingParameters[0].rtx = {
                        ssrc: sendEncodingParameters[0].ssrc + 1
                    };
                }
            }

if (transceiver.wantReceive) {
                transceiver.rtpReceiver = new window.RTCRtpReceiver(
                    transceiver.dtlsTransport, kind);
            }

transceiver.localCapabilities = localCapabilities;
            transceiver.sendEncodingParameters = sendEncodingParameters;
        });

// always offer BUNDLE and dispose on return if not supported.
        if (pc._config.bundlePolicy !== 'max-compat') {
            sdp += 'a=group:BUNDLE ' + pc.transceivers.map(function(t) {
                return t.mid;
            }).join(' ') + '\r\n';
        }
        sdp += 'a=ice-options:trickle\r\n';

pc.transceivers.forEach(function(transceiver, sdpMLineIndex) {
            sdp += writeMediaSection(transceiver, transceiver.localCapabilities,
                'offer', transceiver.stream, pc._dtlsRole);
            sdp += 'a=rtcp-rsize\r\n';

if (transceiver.iceGatherer && pc.iceGatheringState !== 'new' &&
                (sdpMLineIndex === 0 || !pc.usingBundle)) {
                transceiver.iceGatherer.getLocalCandidates().forEach(function(cand) {
                    cand.component = 1;
                    sdp += 'a=' + SDPUtils.writeCandidate(cand) + '\r\n';
                });

if (transceiver.iceGatherer.state === 'completed') {
                    sdp += 'a=end-of-candidates\r\n';
                }
            }
        });

var desc = new window.RTCSessionDescription({
            type: 'offer',
            sdp: sdp
        });
        return Promise.resolve(desc);
    };

RTCPeerConnection.prototype.createAnswer = function() {
        var pc = this;

if (pc._isClosed) {
            return Promise.reject(makeError('InvalidStateError',
                'Can not call createAnswer after close'));
        }

if (!(pc.signalingState === 'have-remote-offer' ||
            pc.signalingState === 'have-local-pranswer')) {
            return Promise.reject(makeError('InvalidStateError',
                'Can not call createAnswer in signalingState ' + pc.signalingState));
        }

// FIXME: look at direction.
            if (transceiver.stream) {
                var localTrack;
                if (transceiver.kind === 'audio') {
                    localTrack = transceiver.stream.getAudioTracks()[0];
                } else if (transceiver.kind === 'video') {
                    localTrack = transceiver.stream.getVideoTracks()[0];
                }
                if (localTrack) {
                    // add RTX
                    if (edgeVersion >= 15019 && transceiver.kind === 'video' &&
                        !transceiver.sendEncodingParameters[0].rtx) {
                        transceiver.sendEncodingParameters[0].rtx = {
                            ssrc: transceiver.sendEncodingParameters[0].ssrc + 1
                        };
                    }
                }
            }

// Calculate intersection of capabilities.
            var commonCapabilities = getCommonCapabilities(
                transceiver.localCapabilities,
                transceiver.remoteCapabilities);

var hasRtx = commonCapabilities.codecs.filter(function(c) {
                return c.name.toLowerCase() === 'rtx';
            }).length;
            if (!hasRtx && transceiver.sendEncodingParameters[0].rtx) {
                delete transceiver.sendEncodingParameters[0].rtx;
            }

sdp += writeMediaSection(transceiver, commonCapabilities,
                'answer', transceiver.stream, pc._dtlsRole);
            if (transceiver.rtcpParameters &&
                transceiver.rtcpParameters.reducedSize) {
                sdp += 'a=rtcp-rsize\r\n';
            }
        });

var desc = new window.RTCSessionDescription({
            type: 'answer',
            sdp: sdp
        });
        return Promise.resolve(desc);
    };

RTCPeerConnection.prototype.addIceCandidate = function(candidate) {
        var pc = this;
        var sections;
        if (candidate && !(candidate.sdpMLineIndex !== undefined ||
            candidate.sdpMid)) {
            return Promise.reject(new TypeError('sdpMLineIndex or sdpMid required'));
        }

// TODO: needs to go into ops queue.
        return new Promise(function(resolve, reject) {
            if (!pc.remoteDescription) {
                return reject(makeError('InvalidStateError',
                    'Can not add ICE candidate without a remote description'));
            } else if (!candidate || candidate.candidate === '') {
                for (var j = 0; j < pc.transceivers.length; j++) {
                    if (pc.transceivers[j].rejected) {
                        continue;
                    }
                    pc.transceivers[j].iceTransport.addRemoteCandidate({});
                    sections = SDPUtils.getMediaSections(pc.remoteDescription.sdp);
                    sections[j] += 'a=end-of-candidates\r\n';
                    pc.remoteDescription.sdp =
                        SDPUtils.getDescription(pc.remoteDescription.sdp) +
                        sections.join('');
                    if (pc.usingBundle) {
                        break;
                    }
                }
            } else {
                var sdpMLineIndex = candidate.sdpMLineIndex;
                if (candidate.sdpMid) {
                    for (var i = 0; i < pc.transceivers.length; i++) {
                        if (pc.transceivers[i].mid === candidate.sdpMid) {
                            sdpMLineIndex = i;
                            break;
                        }
                    }
                }
                var transceiver = pc.transceivers[sdpMLineIndex];
                if (transceiver) {
                    if (transceiver.rejected) {
                        return resolve();
                    }
                    var cand = Object.keys(candidate.candidate).length > 0 ?
                        SDPUtils.parseCandidate(candidate.candidate) : {};
                    // Ignore Chrome's invalid candidates since Edge does not like them.
                    if (cand.protocol === 'tcp' && (cand.port === 0 || cand.port === 9)) {
                        return resolve();
                    }
                    // Ignore RTCP candidates, we assume RTCP-MUX.
                    if (cand.component && cand.component !== 1) {
                        return resolve();
                    }
                    // when using bundle, avoid adding candidates to the wrong
                    // ice transport. And avoid adding candidates added in the SDP.
                    if (sdpMLineIndex === 0 || (sdpMLineIndex > 0 &&
                        transceiver.iceTransport !== pc.transceivers[0].iceTransport)) {
                        if (!maybeAddCandidate(transceiver.iceTransport, cand)) {
                            return reject(makeError('OperationError',
                                'Can not add ICE candidate'));
                        }
                    }

// update the remoteDescription.
                    var candidateString = candidate.candidate.trim();
                    if (candidateString.indexOf('a=') === 0) {
                        candidateString = candidateString.substr(2);
                    }
                    sections = SDPUtils.getMediaSections(pc.remoteDescription.sdp);
                    sections[sdpMLineIndex] += 'a=' +
                        (cand.type ? candidateString : 'end-of-candidates')
                        + '\r\n';
                    pc.remoteDescription.sdp =
                        SDPUtils.getDescription(pc.remoteDescription.sdp) +
                        sections.join('');
                } else {
                    return reject(makeError('OperationError',
                        'Can not add ICE candidate'));
                }
            }
            resolve();
        });
    };

RTCPeerConnection.prototype.getStats = function() {
        var promises = [];
        this.transceivers.forEach(function(transceiver) {
            ['rtpSender', 'rtpReceiver', 'iceGatherer', 'iceTransport',
                'dtlsTransport'].forEach(function(method) {
                if (transceiver[method]) {
                    promises.push(transceiver[method].getStats());
                }
            });
        });
        var fixStatsType = function(stat) {
            return {
                inboundrtp: 'inbound-rtp',
                outboundrtp: 'outbound-rtp',
                candidatepair: 'candidate-pair',
                localcandidate: 'local-candidate',
                remotecandidate: 'remote-candidate'
            }[stat.type] || stat.type;
        };
        return new Promise(function(resolve) {
            // shim getStats with maplike support
            var results = new Map();
            Promise.all(promises).then(function(res) {
                res.forEach(function(result) {
                    Object.keys(result).forEach(function(id) {
                        result[id].type = fixStatsType(result[id]);
                        results.set(id, result[id]);
                    });
                });
                resolve(results);
            });
        });
    };

// legacy callback shims. Should be moved to adapter.js some days.
    var methods = ['createOffer', 'createAnswer'];
    methods.forEach(function(method) {
        var nativeMethod = RTCPeerConnection.prototype[method];
        RTCPeerConnection.prototype[method] = function() {
            var args = arguments;
            if (typeof args[0] === 'function' ||
                typeof args[1] === 'function') { // legacy
                return nativeMethod.apply(this, [arguments[2]])
                    .then(function(description) {
                        if (typeof args[0] === 'function') {
                            args[0].apply(null, [description]);
                        }
                    }, function(error) {
                        if (typeof args[1] === 'function') {
                            args[1].apply(null, [error]);
                        }
                    });
            }
            return nativeMethod.apply(this, arguments);
        };
    });

methods = ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate'];
    methods.forEach(function(method) {
        var nativeMethod = RTCPeerConnection.prototype[method];
        RTCPeerConnection.prototype[method] = function() {
            var args = arguments;
            if (typeof args[1] === 'function' ||
                typeof args[2] === 'function') { // legacy
                return nativeMethod.apply(this, arguments)
                    .then(function() {
                        if (typeof args[1] === 'function') {
                            args[1].apply(null);
                        }
                    }, function(error) {
                        if (typeof args[2] === 'function') {
                            args[2].apply(null, [error]);
                        }
                    });
            }
            return nativeMethod.apply(this, arguments);
        };
    });

// getStats is special. It doesn't have a spec legacy method yet we support
    // getStats(something, cb) without error callbacks.
    ['getStats'].forEach(function(method) {
        var nativeMethod = RTCPeerConnection.prototype[method];
        RTCPeerConnection.prototype[method] = function() {
            var args = arguments;
            if (typeof args[1] === 'function') {
                return nativeMethod.apply(this, arguments)
                    .then(function() {
                        if (typeof args[1] === 'function') {
                            args[1].apply(null);
                        }
                    });
            }
            return nativeMethod.apply(this, arguments);
        };
    });

return RTCPeerConnection;
};

},{"sdp":2}],2:[function(require,module,exports){
/* eslint-env node */
'use strict';

// SDP helpers.
var SDPUtils = {};

// Generate an alphanumeric identifier for cname or mids.
// TODO: use UUIDs instead? https://gist.github.com/jed/982883
SDPUtils.generateIdentifier = function() {
    return Math.random().toString(36).substr(2, 10);
};

// The RTCP CNAME used by all peerconnections from the same JS.
SDPUtils.localCName = SDPUtils.generateIdentifier();

// Splits SDP into lines, dealing with both CRLF and LF.
SDPUtils.splitLines = function(blob) {
    return blob.trim().split('\n').map(function(line) {
        return line.trim();
    });
};
// Splits SDP into sessionpart and mediasections. Ensures CRLF.
SDPUtils.splitSections = function(blob) {
    var parts = blob.split('\nm=');
    return parts.map(function(part, index) {
        return (index > 0 ? 'm=' + part : part).trim() + '\r\n';
    });
};

// returns the session description.
SDPUtils.getDescription = function(blob) {
    var sections = SDPUtils.splitSections(blob);
    return sections && sections[0];
};

// returns the individual media sections.
SDPUtils.getMediaSections = function(blob) {
    var sections = SDPUtils.splitSections(blob);
    sections.shift();
    return sections;
};

// Returns lines that start with a certain prefix.
SDPUtils.matchPrefix = function(blob, prefix) {
    return SDPUtils.splitLines(blob).filter(function(line) {
        return line.indexOf(prefix) === 0;
    });
};

// Parses an ICE candidate line. Sample input:
// candidate:702786350 2 udp 41819902 8.8.8.8 60769 typ relay raddr 8.8.8.8
// rport 55996"
SDPUtils.parseCandidate = function(line) {
    var parts;
    // Parse both variants.
    if (line.indexOf('a=candidate:') === 0) {
        parts = line.substring(12).split(' ');
    } else {
        parts = line.substring(10).split(' ');
    }

var candidate = {
        foundation: parts[0],
        component: parseInt(parts[1], 10),
        protocol: parts[2].toLowerCase(),
        priority: parseInt(parts[3], 10),
        ip: parts[4],
        port: parseInt(parts[5], 10),
        // skip parts[6] == 'typ'
        type: parts[7]
    };

for (var i = 8; i < parts.length; i += 2) {
        switch (parts[i]) {
            case 'raddr':
                candidate.relatedAddress = parts[i + 1];
                break;
            case 'rport':
                candidate.relatedPort = parseInt(parts[i + 1], 10);
                break;
            case 'tcptype':
                candidate.tcpType = parts[i + 1];
                break;
            case 'ufrag':
                candidate.ufrag = parts[i + 1]; // for backward compability.
                candidate.usernameFragment = parts[i + 1];
                break;
            default: // extension handling, in particular ufrag
                candidate[parts[i]] = parts[i + 1];
                break;
        }
    }
    return candidate;
};

// Translates a candidate object into SDP candidate attribute.
SDPUtils.writeCandidate = function(candidate) {
    var sdp = [];
    sdp.push(candidate.foundation);
    sdp.push(candidate.component);
    sdp.push(candidate.protocol.toUpperCase());
    sdp.push(candidate.priority);
    sdp.push(candidate.ip);
    sdp.push(candidate.port);

// Parses an ice-options line, returns an array of option tags.
// a=ice-options:foo bar
SDPUtils.parseIceOptions = function(line) {
    return line.substr(14).split(' ');
}

// Parses an rtpmap line, returns RTCRtpCoddecParameters. Sample input:
// a=rtpmap:111 opus/48000/2
SDPUtils.parseRtpMap = function(line) {
    var parts = line.substr(9).split(' ');
    var parsed = {
        payloadType: parseInt(parts.shift(), 10) // was: id
    };

parts = parts[0].split('/');

parsed.name = parts[0];
    parsed.clockRate = parseInt(parts[1], 10); // was: clockrate
    // was: channels
    parsed.numChannels = parts.length === 3 ? parseInt(parts[2], 10) : 1;
    return parsed;
};

// Generate an a=rtpmap line from RTCRtpCodecCapability or
// RTCRtpCodecParameters.
SDPUtils.writeRtpMap = function(codec) {
    var pt = codec.payloadType;
    if (codec.preferredPayloadType !== undefined) {
        pt = codec.preferredPayloadType;
    }
    return 'a=rtpmap:' + pt + ' ' + codec.name + '/' + codec.clockRate +
        (codec.numChannels !== 1 ? '/' + codec.numChannels : '') + '\r\n';
};

// Parses an a=extmap line (headerextension from RFC 5285). Sample input:
// a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
// a=extmap:2/sendonly urn:ietf:params:rtp-hdrext:toffset
SDPUtils.parseExtmap = function(line) {
    var parts = line.substr(9).split(' ');
    return {
        id: parseInt(parts[0], 10),
        direction: parts[0].indexOf('/') > 0 ? parts[0].split('/')[1] : 'sendrecv',
        uri: parts[1]
    };
};

// Generates a=extmap line from RTCRtpHeaderExtensionParameters or
// RTCRtpHeaderExtension.
SDPUtils.writeExtmap = function(headerExtension) {
    return 'a=extmap:' + (headerExtension.id || headerExtension.preferredId) +
        (headerExtension.direction && headerExtension.direction !== 'sendrecv'
            ? '/' + headerExtension.direction
            : '') +
        ' ' + headerExtension.uri + '\r\n';
};

// Parses an ftmp line, returns dictionary. Sample input:
// a=fmtp:96 vbr=on;cng=on
// Also deals with vbr=on; cng=on
SDPUtils.parseFmtp = function(line) {
    var parsed = {};
    var kv;
    var parts = line.substr(line.indexOf(' ') + 1).split(';');
    for (var j = 0; j < parts.length; j++) {
        kv = parts[j].trim().split('=');
        parsed[kv[0].trim()] = kv[1];
    }
    return parsed;
};

// Generates an a=ftmp line from RTCRtpCodecCapability or RTCRtpCodecParameters.
SDPUtils.writeFmtp = function(codec) {
    var line = '';
    var pt = codec.payloadType;
    if (codec.preferredPayloadType !== undefined) {
        pt = codec.preferredPayloadType;
    }
    if (codec.parameters && Object.keys(codec.parameters).length) {
        var params = [];
        Object.keys(codec.parameters).forEach(function(param) {
            params.push(param + '=' + codec.parameters[param]);
        });
        line += 'a=fmtp:' + pt + ' ' + params.join(';') + '\r\n';
    }
    return line;
};

// Parses an rtcp-fb line, returns RTCPRtcpFeedback object. Sample input:
// a=rtcp-fb:98 nack rpsi
SDPUtils.parseRtcpFb = function(line) {
    var parts = line.substr(line.indexOf(' ') + 1).split(' ');
    return {
        type: parts.shift(),
        parameter: parts.join(' ')
    };
};
// Generate a=rtcp-fb lines from RTCRtpCodecCapability or RTCRtpCodecParameters.
SDPUtils.writeRtcpFb = function(codec) {
    var lines = '';
    var pt = codec.payloadType;
    if (codec.preferredPayloadType !== undefined) {
        pt = codec.preferredPayloadType;
    }
    if (codec.rtcpFeedback && codec.rtcpFeedback.length) {
        // FIXME: special handling for trr-int?
        codec.rtcpFeedback.forEach(function(fb) {
            lines += 'a=rtcp-fb:' + pt + ' ' + fb.type +
                (fb.parameter && fb.parameter.length ? ' ' + fb.parameter : '') +
                '\r\n';
        });
    }
    return lines;
};

// Parses an RFC 5576 ssrc media attribute. Sample input:
// a=ssrc:3735928559 cname:something
SDPUtils.parseSsrcMedia = function(line) {
    var sp = line.indexOf(' ');
    var parts = {
        ssrc: parseInt(line.substr(7, sp - 7), 10)
    };
    var colon = line.indexOf(':', sp);
    if (colon > -1) {
        parts.attribute = line.substr(sp + 1, colon - sp - 1);
        parts.value = line.substr(colon + 1);
    } else {
        parts.attribute = line.substr(sp + 1);
    }
    return parts;
};

// Extracts the MID (RFC 5888) from a media section.
// returns the MID or undefined if no mid line was found.
SDPUtils.getMid = function(mediaSection) {
    var mid = SDPUtils.matchPrefix(mediaSection, 'a=mid:')[0];
    if (mid) {
        return mid.substr(6);
    }
}

SDPUtils.parseFingerprint = function(line) {
    var parts = line.substr(14).split(' ');
    return {
        algorithm: parts[0].toLowerCase(), // algorithm is case-sensitive in Edge.
        value: parts[1]
    };
};

// Extracts DTLS parameters from SDP media section or sessionpart.
// FIXME: for consistency with other functions this should only
//   get the fingerprint line as input. See also getIceParameters.
SDPUtils.getDtlsParameters = function(mediaSection, sessionpart) {
    var lines = SDPUtils.matchPrefix(mediaSection + sessionpart,
        'a=fingerprint:');
    // Note: a=setup line is ignored since we use the 'auto' role.
    // Note2: 'algorithm' is not case sensitive except in Edge.
    return {
        role: 'auto',
        fingerprints: lines.map(SDPUtils.parseFingerprint)
    };
};

// Serializes DTLS parameters to SDP.
SDPUtils.writeDtlsParameters = function(params, setupType) {
    var sdp = 'a=setup:' + setupType + '\r\n';
    params.fingerprints.forEach(function(fp) {
        sdp += 'a=fingerprint:' + fp.algorithm + ' ' + fp.value + '\r\n';
    });
    return sdp;
};
// Parses ICE information from SDP media section or sessionpart.
// FIXME: for consistency with other functions this should only
//   get the ice-ufrag and ice-pwd lines as input.
SDPUtils.getIceParameters = function(mediaSection, sessionpart) {
    var lines = SDPUtils.splitLines(mediaSection);
    // Search in session part, too.
    lines = lines.concat(SDPUtils.splitLines(sessionpart));
    var iceParameters = {
        usernameFragment: lines.filter(function(line) {
            return line.indexOf('a=ice-ufrag:') === 0;
        })[0].substr(12),
        password: lines.filter(function(line) {
            return line.indexOf('a=ice-pwd:') === 0;
        })[0].substr(10)
    };
    return iceParameters;
};

// Serializes ICE parameters to SDP.
SDPUtils.writeIceParameters = function(params) {
    return 'a=ice-ufrag:' + params.usernameFragment + '\r\n' +
        'a=ice-pwd:' + params.password + '\r\n';
};

// Parses the SDP media section and returns RTCRtpParameters.
SDPUtils.parseRtpParameters = function(mediaSection) {
    var description = {
        codecs: [],
        headerExtensions: [],
        fecMechanisms: [],
        rtcp: []
    };
    var lines = SDPUtils.splitLines(mediaSection);
    var mline = lines[0].split(' ');
    for (var i = 3; i < mline.length; i++) { // find all codecs from mline[3..]
        var pt = mline[i];
        var rtpmapline = SDPUtils.matchPrefix(
            mediaSection, 'a=rtpmap:' + pt + ' ')[0];
        if (rtpmapline) {
            var codec = SDPUtils.parseRtpMap(rtpmapline);
            var fmtps = SDPUtils.matchPrefix(
                mediaSection, 'a=fmtp:' + pt + ' ');
            // Only the first a=fmtp:<pt> is considered.
            codec.parameters = fmtps.length ? SDPUtils.parseFmtp(fmtps[0]) : {};
            codec.rtcpFeedback = SDPUtils.matchPrefix(
                mediaSection, 'a=rtcp-fb:' + pt + ' ')
                .map(SDPUtils.parseRtcpFb);
            description.codecs.push(codec);
            // parse FEC mechanisms from rtpmap lines.
            switch (codec.name.toUpperCase()) {
                case 'RED':
                case 'ULPFEC':
                    description.fecMechanisms.push(codec.name.toUpperCase());
                    break;
                default: // only RED and ULPFEC are recognized as FEC mechanisms.
                    break;
            }
        }
    }
    SDPUtils.matchPrefix(mediaSection, 'a=extmap:').forEach(function(line) {
        description.headerExtensions.push(SDPUtils.parseExtmap(line));
    });
    // FIXME: parse rtcp.
    return description;
};

// Generates parts of the SDP media section describing the capabilities /
// parameters.
SDPUtils.writeRtpDescription = function(kind, caps) {
    var sdp = '';

// Build the mline.
    sdp += 'm=' + kind + ' ';
    sdp += caps.codecs.length > 0 ? '9' : '0'; // reject if no codecs.
    sdp += ' UDP/TLS/RTP/SAVPF ';
    sdp += caps.codecs.map(function(codec) {
        if (codec.preferredPayloadType !== undefined) {
            return codec.preferredPayloadType;
        }
        return codec.payloadType;
    }).join(' ') + '\r\n';

sdp += 'c=IN IP4 0.0.0.0\r\n';
    sdp += 'a=rtcp:9 IN IP4 0.0.0.0\r\n';

// Add a=rtpmap lines for each codec. Also fmtp and rtcp-fb.
    caps.codecs.forEach(function(codec) {
        sdp += SDPUtils.writeRtpMap(codec);
        sdp += SDPUtils.writeFmtp(codec);
        sdp += SDPUtils.writeRtcpFb(codec);
    });
    var maxptime = 0;
    caps.codecs.forEach(function(codec) {
        if (codec.maxptime > maxptime) {
            maxptime = codec.maxptime;
        }
    });
    if (maxptime > 0) {
        sdp += 'a=maxptime:' + maxptime + '\r\n';
    }
    sdp += 'a=rtcp-mux\r\n';

caps.headerExtensions.forEach(function(extension) {
        sdp += SDPUtils.writeExtmap(extension);
    });
    // FIXME: write fecMechanisms.
    return sdp;
};

// Parses the SDP media section and returns an array of
// RTCRtpEncodingParameters.
SDPUtils.parseRtpEncodingParameters = function(mediaSection) {
    var encodingParameters = [];
    var description = SDPUtils.parseRtpParameters(mediaSection);
    var hasRed = description.fecMechanisms.indexOf('RED') !== -1;
    var hasUlpfec = description.fecMechanisms.indexOf('ULPFEC') !== -1;

// filter a=ssrc:... cname:, ignore PlanB-msid
    var ssrcs = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
        .map(function(line) {
            return SDPUtils.parseSsrcMedia(line);
        })
        .filter(function(parts) {
            return parts.attribute === 'cname';
        });
    var primarySsrc = ssrcs.length > 0 && ssrcs[0].ssrc;
    var secondarySsrc;

description.codecs.forEach(function(codec) {
        if (codec.name.toUpperCase() === 'RTX' && codec.parameters.apt) {
            var encParam = {
                ssrc: primarySsrc,
                codecPayloadType: parseInt(codec.parameters.apt, 10),
                rtx: {
                    ssrc: secondarySsrc
                }
            };
            encodingParameters.push(encParam);
            if (hasRed) {
                encParam = JSON.parse(JSON.stringify(encParam));
                encParam.fec = {
                    ssrc: secondarySsrc,
                    mechanism: hasUlpfec ? 'red+ulpfec' : 'red'
                };
                encodingParameters.push(encParam);
            }
        }
    });
    if (encodingParameters.length === 0 && primarySsrc) {
        encodingParameters.push({
            ssrc: primarySsrc
        });
    }

// we support both b=AS and b=TIAS but interpret AS as TIAS.
    var bandwidth = SDPUtils.matchPrefix(mediaSection, 'b=');
    if (bandwidth.length) {
        if (bandwidth[0].indexOf('b=TIAS:') === 0) {
            bandwidth = parseInt(bandwidth[0].substr(7), 10);
        } else if (bandwidth[0].indexOf('b=AS:') === 0) {
            // use formula from JSEP to convert b=AS to TIAS value.
            bandwidth = parseInt(bandwidth[0].substr(5), 10) * 1000 * 0.95
                - (50 * 40 * 8);
        } else {
            bandwidth = undefined;
        }
        encodingParameters.forEach(function(params) {
            params.maxBitrate = bandwidth;
        });
    }
    return encodingParameters;
};

// parses http://draft.ortc.org/#rtcrtcpparameters*
SDPUtils.parseRtcpParameters = function(mediaSection) {
    var rtcpParameters = {};

var cname;
    // Gets the first SSRC. Note that with RTX there might be multiple
    // SSRCs.
    var remoteSsrc = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
        .map(function(line) {
            return SDPUtils.parseSsrcMedia(line);
        })
        .filter(function(obj) {
            return obj.attribute === 'cname';
        })[0];
    if (remoteSsrc) {
        rtcpParameters.cname = remoteSsrc.value;
        rtcpParameters.ssrc = remoteSsrc.ssrc;
    }

// Edge uses the compound attribute instead of reducedSize
    // compound is !reducedSize
    var rsize = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-rsize');
    rtcpParameters.reducedSize = rsize.length > 0;
    rtcpParameters.compound = rsize.length === 0;

// parses the rtcp-mux attrÑ–bute.
    // Note that Edge does not support unmuxed RTCP.
    var mux = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-mux');
    rtcpParameters.mux = mux.length > 0;

return rtcpParameters;
};

// parses either a=msid: or a=ssrc:... msid lines and returns
// the id of the MediaStream and MediaStreamTrack.
SDPUtils.parseMsid = function(mediaSection) {
    var parts;
    var spec = SDPUtils.matchPrefix(mediaSection, 'a=msid:');
    if (spec.length === 1) {
        parts = spec[0].substr(7).split(' ');
        return {stream: parts[0], track: parts[1]};
    }
    var planB = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
        .map(function(line) {
            return SDPUtils.parseSsrcMedia(line);
        })
        .filter(function(parts) {
            return parts.attribute === 'msid';
        });
    if (planB.length > 0) {
        parts = planB[0].value.split(' ');
        return {stream: parts[0], track: parts[1]};
    }
};

// Generate a session ID for SDP.
// https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-20#section-5.2.1
// recommends using a cryptographically random +ve 64-bit value
// but right now this should be acceptable and within the right range
SDPUtils.generateSessionId = function() {
    return Math.random().toString().substr(2, 21);
};

// Write boilder plate for start of SDP
// sessId argument is optional - if not supplied it will
// be generated randomly
// sessVersion is optional and defaults to 2
SDPUtils.writeSessionBoilerplate = function(sessId, sessVer) {
    var sessionId;
    var version = sessVer !== undefined ? sessVer : 2;
    if (sessId) {
        sessionId = sessId;
    } else {
        sessionId = SDPUtils.generateSessionId();
    }
    // FIXME: sess-id should be an NTP timestamp.
    return 'v=0\r\n' +
        'o=thisisadapterortc ' + sessionId + ' ' + version + ' IN IP4 127.0.0.1\r\n' +
        's=-\r\n' +
        't=0 0\r\n';
};

SDPUtils.writeMediaSection = function(transceiver, caps, type, stream) {
    var sdp = SDPUtils.writeRtpDescription(transceiver.kind, caps);

// Map ICE parameters (ufrag, pwd) to SDP.
    sdp += SDPUtils.writeIceParameters(
        transceiver.iceGatherer.getLocalParameters());

// Map DTLS parameters to SDP.
    sdp += SDPUtils.writeDtlsParameters(
        transceiver.dtlsTransport.getLocalParameters(),
        type === 'offer' ? 'actpass' : 'active');

sdp += 'a=mid:' + transceiver.mid + '\r\n';

if (transceiver.direction) {
        sdp += 'a=' + transceiver.direction + '\r\n';
    } else if (transceiver.rtpSender && transceiver.rtpReceiver) {
        sdp += 'a=sendrecv\r\n';
    } else if (transceiver.rtpSender) {
        sdp += 'a=sendonly\r\n';
    } else if (transceiver.rtpReceiver) {
        sdp += 'a=recvonly\r\n';
    } else {
        sdp += 'a=inactive\r\n';
    }

if (transceiver.rtpSender) {
        // spec.
        var msid = 'msid:' + stream.id + ' ' +
            transceiver.rtpSender.track.id + '\r\n';
        sdp += 'a=' + msid;

// for Chrome.
        sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
            ' ' + msid;
        if (transceiver.sendEncodingParameters[0].rtx) {
            sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
                ' ' + msid;
            sdp += 'a=ssrc-group:FID ' +
                transceiver.sendEncodingParameters[0].ssrc + ' ' +
                transceiver.sendEncodingParameters[0].rtx.ssrc +
                '\r\n';
        }
    }
    // FIXME: this should be written by writeRtpDescription.
    sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
        ' cname:' + SDPUtils.localCName + '\r\n';
    if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
        sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
            ' cname:' + SDPUtils.localCName + '\r\n';
    }
    return sdp;
};

// Gets the direction from the mediaSection or the sessionpart.
SDPUtils.getDirection = function(mediaSection, sessionpart) {
    // Look for sendrecv, sendonly, recvonly, inactive, default to sendrecv.
    var lines = SDPUtils.splitLines(mediaSection);
    for (var i = 0; i < lines.length; i++) {
        switch (lines[i]) {
            case 'a=sendrecv':
            case 'a=sendonly':
            case 'a=recvonly':
            case 'a=inactive':
                return lines[i].substr(2);
            default:
            // FIXME: What should happen here?
        }
    }
    if (sessionpart) {
        return SDPUtils.getDirection(sessionpart);
    }
    return 'sendrecv';
};

SDPUtils.getKind = function(mediaSection) {
    var lines = SDPUtils.splitLines(mediaSection);
    var mline = lines[0].split(' ');
    return mline[0].substr(2);
};

SDPUtils.isRejected = function(mediaSection) {
    return mediaSection.split(' ', 2)[1] === '0';
};

SDPUtils.parseMLine = function(mediaSection) {
    var lines = SDPUtils.splitLines(mediaSection);
    var parts = lines[0].substr(2).split(' ');
    return {
        kind: parts[0],
        port: parseInt(parts[1], 10),
        protocol: parts[2],
        fmt: parts.slice(3).join(' ')
    };
};

SDPUtils.parseOLine = function(mediaSection) {
    var line = SDPUtils.matchPrefix(mediaSection, 'o=')[0];
    var parts = line.substr(2).split(' ');
    return {
        username: parts[0],
        sessionId: parts[1],
        sessionVersion: parseInt(parts[2], 10),
        netType: parts[3],
        addressType: parts[4],
        address: parts[5],
    };
}

// Expose public methods.
if (typeof module === 'object') {
    module.exports = SDPUtils;
}

},{}],3:[function(require,module,exports){
(function (global){
    /*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
    /* eslint-env node */

'use strict';

var adapterFactory = require('./adapter_factory.js');
    module.exports = adapterFactory({window: global.window});

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./adapter_factory.js":4}],4:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */

'use strict';

var utils = require('./utils');
// Shimming starts here.
module.exports = function(dependencies, opts) {
    var window = dependencies && dependencies.window;

var options = {
        shimChrome: true,
        shimFirefox: true,
        shimEdge: true,
        shimSafari: true,
    };

for (var key in opts) {
        if (hasOwnProperty.call(opts, key)) {
            options[key] = opts[key];
        }
    }

// Utils.
    var logging = utils.log;
    var browserDetails = utils.detectBrowser(window);

// Uncomment the line below if you want logging to occur, including logging
    // for the switch statement below. Can also be turned on in the browser via
    // adapter.disableLog(false), but then logging from the switch statement below
    // will not appear.
    // require('./utils').disableLog(false);

// Browser shims.
    var chromeShim = require('./chrome/chrome_shim') || null;
    var edgeShim = require('./edge/edge_shim') || null;
    var firefoxShim = require('./firefox/firefox_shim') || null;
    var safariShim = require('./safari/safari_shim') || null;
    var commonShim = require('./common_shim') || null;

// Export to the adapter global object visible in the browser.
    var adapter = {
        browserDetails: browserDetails,
        commonShim: commonShim,
        extractVersion: utils.extractVersion,
        disableLog: utils.disableLog,
        disableWarnings: utils.disableWarnings
    };

// Shim browser if found.
    switch (browserDetails.browser) {
        case 'chrome':
            if (!chromeShim || !chromeShim.shimPeerConnection ||
                !options.shimChrome) {
                logging('Chrome shim is not included in this adapter release.');
                return adapter;
            }
            logging('adapter.js shimming chrome.');
            // Export to the adapter global object visible in the browser.
            adapter.browserShim = chromeShim;
            commonShim.shimCreateObjectURL(window);

chromeShim.shimGetUserMedia(window);
            chromeShim.shimMediaStream(window);
            chromeShim.shimSourceObject(window);
            chromeShim.shimPeerConnection(window);
            chromeShim.shimOnTrack(window);
            chromeShim.shimAddTrackRemoveTrack(window);
            chromeShim.shimGetSendersWithDtmf(window);

commonShim.shimRTCIceCandidate(window);
            commonShim.shimMaxMessageSize(window);
            commonShim.shimSendThrowTypeError(window);
            break;
        case 'firefox':
            if (!firefoxShim || !firefoxShim.shimPeerConnection ||
                !options.shimFirefox) {
                logging('Firefox shim is not included in this adapter release.');
                return adapter;
            }
            logging('adapter.js shimming firefox.');
            // Export to the adapter global object visible in the browser.
            adapter.browserShim = firefoxShim;
            commonShim.shimCreateObjectURL(window);

firefoxShim.shimGetUserMedia(window);
            firefoxShim.shimSourceObject(window);
            firefoxShim.shimPeerConnection(window);
            firefoxShim.shimOnTrack(window);
            firefoxShim.shimRemoveStream(window);

commonShim.shimRTCIceCandidate(window);
            commonShim.shimMaxMessageSize(window);
            commonShim.shimSendThrowTypeError(window);
            break;
        case 'edge':
            if (!edgeShim || !edgeShim.shimPeerConnection || !options.shimEdge) {
                logging('MS edge shim is not included in this adapter release.');
                return adapter;
            }
            logging('adapter.js shimming edge.');
            // Export to the adapter global object visible in the browser.
            adapter.browserShim = edgeShim;
            commonShim.shimCreateObjectURL(window);

edgeShim.shimGetUserMedia(window);
            edgeShim.shimPeerConnection(window);
            edgeShim.shimReplaceTrack(window);

// the edge shim implements the full RTCIceCandidate object.

commonShim.shimMaxMessageSize(window);
            commonShim.shimSendThrowTypeError(window);
            break;
        case 'safari':
            if (!safariShim || !options.shimSafari) {
                logging('Safari shim is not included in this adapter release.');
                return adapter;
            }
            logging('adapter.js shimming safari.');
            // Export to the adapter global object visible in the browser.
            adapter.browserShim = safariShim;
            commonShim.shimCreateObjectURL(window);

safariShim.shimRTCIceServerUrls(window);
            safariShim.shimCallbacksAPI(window);
            safariShim.shimLocalStreamsAPI(window);
            safariShim.shimRemoteStreamsAPI(window);
            safariShim.shimTrackEventTransceiver(window);
            safariShim.shimGetUserMedia(window);
            safariShim.shimCreateOfferLegacy(window);

commonShim.shimRTCIceCandidate(window);
            commonShim.shimMaxMessageSize(window);
            commonShim.shimSendThrowTypeError(window);
            break;
        default:
            logging('Unsupported browser!');
            break;
    }

return adapter;
};

},{"./chrome/chrome_shim":5,"./common_shim":7,"./edge/edge_shim":8,"./firefox/firefox_shim":10,"./safari/safari_shim":12,"./utils":13}],5:[function(require,module,exports){

/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';
var utils = require('../utils.js');
var logging = utils.log;

module.exports = {
    shimGetUserMedia: require('./getusermedia'),
    shimMediaStream: function(window) {
        window.MediaStream = window.MediaStream || window.webkitMediaStream;
    },

shimOnTrack: function(window) {
        if (typeof window === 'object' && window.RTCPeerConnection && !('ontrack' in
            window.RTCPeerConnection.prototype)) {
            Object.defineProperty(window.RTCPeerConnection.prototype, 'ontrack', {
                get: function() {
                    return this._ontrack;
                },
                set: function(f) {
                    if (this._ontrack) {
                        this.removeEventListener('track', this._ontrack);
                    }
                    this.addEventListener('track', this._ontrack = f);
                }
            });
            var origSetRemoteDescription =
                window.RTCPeerConnection.prototype.setRemoteDescription;
            window.RTCPeerConnection.prototype.setRemoteDescription = function() {
                var pc = this;
                if (!pc._ontrackpoly) {
                    pc._ontrackpoly = function(e) {
                        // onaddstream does not fire when a track is added to an existing
                        // stream. But stream.onaddtrack is implemented so we use that.
                        e.stream.addEventListener('addtrack', function(te) {
                            var receiver;
                            if (window.RTCPeerConnection.prototype.getReceivers) {
                                receiver = pc.getReceivers().find(function(r) {
                                    return r.track && r.track.id === te.track.id;
                                });
                            } else {
                                receiver = {track: te.track};
                            }

shimGetSendersWithDtmf: function(window) {
        // Overrides addTrack/removeTrack, depends on shimAddTrackRemoveTrack.
        if (typeof window === 'object' && window.RTCPeerConnection &&
            !('getSenders' in window.RTCPeerConnection.prototype) &&
            'createDTMFSender' in window.RTCPeerConnection.prototype) {
            var shimSenderWithDtmf = function(pc, track) {
                return {
                    track: track,
                    get dtmf() {
                        if (this._dtmf === undefined) {
                            if (track.kind === 'audio') {
                                this._dtmf = pc.createDTMFSender(track);
                            } else {
                                this._dtmf = null;
                            }
                        }
                        return this._dtmf;
                    },
                    _pc: pc
                };
            };

// augment addTrack when getSenders is not available.
            if (!window.RTCPeerConnection.prototype.getSenders) {
                window.RTCPeerConnection.prototype.getSenders = function() {
                    this._senders = this._senders || [];
                    return this._senders.slice(); // return a copy of the internal state.
                };
                var origAddTrack = window.RTCPeerConnection.prototype.addTrack;
                window.RTCPeerConnection.prototype.addTrack = function(track, stream) {
                    var pc = this;
                    var sender = origAddTrack.apply(pc, arguments);
                    if (!sender) {
                        sender = shimSenderWithDtmf(pc, track);
                        pc._senders.push(sender);
                    }
                    return sender;
                };

var origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
            window.RTCPeerConnection.prototype.removeStream = function(stream) {
                var pc = this;
                pc._senders = pc._senders || [];
                origRemoveStream.apply(pc, [stream]);

stream.getTracks().forEach(function(track) {
                    var sender = pc._senders.find(function(s) {
                        return s.track === track;
                    });
                    if (sender) {
                        pc._senders.splice(pc._senders.indexOf(sender), 1); // remove sender
                    }
                });
            };
        } else if (typeof window === 'object' && window.RTCPeerConnection &&
            'getSenders' in window.RTCPeerConnection.prototype &&
            'createDTMFSender' in window.RTCPeerConnection.prototype &&
            window.RTCRtpSender &&
            !('dtmf' in window.RTCRtpSender.prototype)) {
            var origGetSenders = window.RTCPeerConnection.prototype.getSenders;
            window.RTCPeerConnection.prototype.getSenders = function() {
                var pc = this;
                var senders = origGetSenders.apply(pc, []);
                senders.forEach(function(sender) {
                    sender._pc = pc;
                });
                return senders;
            };

Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
                get: function() {
                    if (this._dtmf === undefined) {
                        if (this.track.kind === 'audio') {
                            this._dtmf = this._pc.createDTMFSender(this.track);
                        } else {
                            this._dtmf = null;
                        }
                    }
                    return this._dtmf;
                }
            });
        }
    },

shimSourceObject: function(window) {
        var URL = window && window.URL;

if (typeof window === 'object') {
            if (window.HTMLMediaElement &&
                !('srcObject' in window.HTMLMediaElement.prototype)) {
                // Shim the srcObject property, once, when HTMLMediaElement is found.
                Object.defineProperty(window.HTMLMediaElement.prototype, 'srcObject', {
                    get: function() {
                        return this._srcObject;
                    },
                    set: function(stream) {
                        var self = this;
                        // Use _srcObject as a private property for this shim
                        this._srcObject = stream;
                        if (this.src) {
                            URL.revokeObjectURL(this.src);
                        }

if (!stream) {
                            this.src = '';
                            return undefined;
                        }
                        this.src = URL.createObjectURL(stream);
                        // We need to recreate the blob url when a track is added or
                        // removed. Doing it manually since we want to avoid a recursion.
                        stream.addEventListener('addtrack', function() {
                            if (self.src) {
                                URL.revokeObjectURL(self.src);
                            }
                            self.src = URL.createObjectURL(stream);
                        });
                        stream.addEventListener('removetrack', function() {
                            if (self.src) {
                                URL.revokeObjectURL(self.src);
                            }
                            self.src = URL.createObjectURL(stream);
                        });
                    }
                });
            }
        }
    },

shimAddTrackRemoveTrackWithNative: function(window) {
        // shim addTrack/removeTrack with native variants in order to make
        // the interactions with legacy getLocalStreams behave as in other browsers.
        // Keeps a mapping stream.id => [stream, rtpsenders...]
        window.RTCPeerConnection.prototype.getLocalStreams = function() {
            var pc = this;
            this._shimmedLocalStreams = this._shimmedLocalStreams || {};
            return Object.keys(this._shimmedLocalStreams).map(function(streamId) {
                return pc._shimmedLocalStreams[streamId][0];
            });
        };

var origAddTrack = window.RTCPeerConnection.prototype.addTrack;
        window.RTCPeerConnection.prototype.addTrack = function(track, stream) {
            if (!stream) {
                return origAddTrack.apply(this, arguments);
            }
            this._shimmedLocalStreams = this._shimmedLocalStreams || {};

var sender = origAddTrack.apply(this, arguments);
            if (!this._shimmedLocalStreams[stream.id]) {
                this._shimmedLocalStreams[stream.id] = [stream, sender];
            } else if (this._shimmedLocalStreams[stream.id].indexOf(sender) === -1) {
                this._shimmedLocalStreams[stream.id].push(sender);
            }
            return sender;
        };

var origAddStream = window.RTCPeerConnection.prototype.addStream;
        window.RTCPeerConnection.prototype.addStream = function(stream) {
            var pc = this;
            this._shimmedLocalStreams = this._shimmedLocalStreams || {};

stream.getTracks().forEach(function(track) {
                var alreadyExists = pc.getSenders().find(function(s) {
                    return s.track === track;
                });
                if (alreadyExists) {
                    throw new DOMException('Track already exists.',
                        'InvalidAccessError');
                }
            });
            var existingSenders = pc.getSenders();
            origAddStream.apply(this, arguments);
            var newSenders = pc.getSenders().filter(function(newSender) {
                return existingSenders.indexOf(newSender) === -1;
            });
            this._shimmedLocalStreams[stream.id] = [stream].concat(newSenders);
        };

var origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
        window.RTCPeerConnection.prototype.removeStream = function(stream) {
            this._shimmedLocalStreams = this._shimmedLocalStreams || {};
            delete this._shimmedLocalStreams[stream.id];
            return origRemoveStream.apply(this, arguments);
        };

shimAddTrackRemoveTrack: function(window) {
        var browserDetails = utils.detectBrowser(window);
        // shim addTrack and removeTrack.
        if (window.RTCPeerConnection.prototype.addTrack &&
            browserDetails.version >= 65) {
            return this.shimAddTrackRemoveTrackWithNative(window);
        }

// also shim pc.getLocalStreams when addTrack is shimmed
        // to return the original streams.
        var origGetLocalStreams = window.RTCPeerConnection.prototype
            .getLocalStreams;
        window.RTCPeerConnection.prototype.getLocalStreams = function() {
            var pc = this;
            var nativeStreams = origGetLocalStreams.apply(this);
            pc._reverseStreams = pc._reverseStreams || {};
            return nativeStreams.map(function(stream) {
                return pc._reverseStreams[stream.id];
            });
        };

var origAddStream = window.RTCPeerConnection.prototype.addStream;
        window.RTCPeerConnection.prototype.addStream = function(stream) {
            var pc = this;
            pc._streams = pc._streams || {};
            pc._reverseStreams = pc._reverseStreams || {};

stream.getTracks().forEach(function(track) {
                var alreadyExists = pc.getSenders().find(function(s) {
                    return s.track === track;
                });
                if (alreadyExists) {
                    throw new DOMException('Track already exists.',
                        'InvalidAccessError');
                }
            });
            // Add identity mapping for consistency with addTrack.
            // Unless this is being used with a stream from addTrack.
            if (!pc._reverseStreams[stream.id]) {
                var newStream = new window.MediaStream(stream.getTracks());
                pc._streams[stream.id] = newStream;
                pc._reverseStreams[newStream.id] = stream;
                stream = newStream;
            }
            origAddStream.apply(pc, [stream]);
        };

var origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
        window.RTCPeerConnection.prototype.removeStream = function(stream) {
            var pc = this;
            pc._streams = pc._streams || {};
            pc._reverseStreams = pc._reverseStreams || {};

origRemoveStream.apply(pc, [(pc._streams[stream.id] || stream)]);
            delete pc._reverseStreams[(pc._streams[stream.id] ?
                pc._streams[stream.id].id : stream.id)];
            delete pc._streams[stream.id];
        };

var alreadyExists = pc.getSenders().find(function(s) {
                return s.track === track;
            });
            if (alreadyExists) {
                throw new DOMException('Track already exists.',
                    'InvalidAccessError');
            }

pc._streams = pc._streams || {};
            pc._reverseStreams = pc._reverseStreams || {};
            var oldStream = pc._streams[stream.id];
            if (oldStream) {
                // this is using odd Chrome behaviour, use with caution:
                // https://bugs.chromium.org/p/webrtc/issues/detail?id=7815
                // Note: we rely on the high-level addTrack/dtmf shim to
                // create the sender with a dtmf sender.
                oldStream.addTrack(track);

// Trigger ONN async.
                Promise.resolve().then(function() {
                    pc.dispatchEvent(new Event('negotiationneeded'));
                });
            } else {
                var newStream = new window.MediaStream([track]);
                pc._streams[stream.id] = newStream;
                pc._reverseStreams[newStream.id] = stream;
                pc.addStream(newStream);
            }
            return pc.getSenders().find(function(s) {
                return s.track === track;
            });
        };

// replace the internal stream id with the external one and
        // vice versa.
        function replaceInternalStreamId(pc, description) {
            var sdp = description.sdp;
            Object.keys(pc._reverseStreams || []).forEach(function(internalId) {
                var externalStream = pc._reverseStreams[internalId];
                var internalStream = pc._streams[externalStream.id];
                sdp = sdp.replace(new RegExp(internalStream.id, 'g'),
                    externalStream.id);
            });
            return new RTCSessionDescription({
                type: description.type,
                sdp: sdp
            });
        }
        function replaceExternalStreamId(pc, description) {
            var sdp = description.sdp;
            Object.keys(pc._reverseStreams || []).forEach(function(internalId) {
                var externalStream = pc._reverseStreams[internalId];
                var internalStream = pc._streams[externalStream.id];
                sdp = sdp.replace(new RegExp(externalStream.id, 'g'),
                    internalStream.id);
            });
            return new RTCSessionDescription({
                type: description.type,
                sdp: sdp
            });
        }
        ['createOffer', 'createAnswer'].forEach(function(method) {
            var nativeMethod = window.RTCPeerConnection.prototype[method];
            window.RTCPeerConnection.prototype[method] = function() {
                var pc = this;
                var args = arguments;
                var isLegacyCall = arguments.length &&
                    typeof arguments[0] === 'function';
                if (isLegacyCall) {
                    return nativeMethod.apply(pc, [
                        function(description) {
                            var desc = replaceInternalStreamId(pc, description);
                            args[0].apply(null, [desc]);
                        },
                        function(err) {
                            if (args[1]) {
                                args[1].apply(null, err);
                            }
                        }, arguments[2]
                    ]);
                }
                return nativeMethod.apply(pc, arguments)
                    .then(function(description) {
                        return replaceInternalStreamId(pc, description);
                    });
            };
        });

var origSetLocalDescription =
            window.RTCPeerConnection.prototype.setLocalDescription;
        window.RTCPeerConnection.prototype.setLocalDescription = function() {
            var pc = this;
            if (!arguments.length || !arguments[0].type) {
                return origSetLocalDescription.apply(pc, arguments);
            }
            arguments[0] = replaceExternalStreamId(pc, arguments[0]);
            return origSetLocalDescription.apply(pc, arguments);
        };

// TODO: mangle getStats: https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamstats-streamidentifier

// Search for the native stream the senders track belongs to.
            pc._streams = pc._streams || {};
            var stream;
            Object.keys(pc._streams).forEach(function(streamid) {
                var hasTrack = pc._streams[streamid].getTracks().find(function(track) {
                    return sender.track === track;
                });
                if (hasTrack) {
                    stream = pc._streams[streamid];
                }
            });

if (stream) {
                if (stream.getTracks().length === 1) {
                    // if this is the last track of the stream, remove the stream. This
                    // takes care of any shimmed _senders.
                    pc.removeStream(pc._reverseStreams[stream.id]);
                } else {
                    // relying on the same odd chrome behaviour as above.
                    stream.removeTrack(sender.track);
                }
                pc.dispatchEvent(new Event('negotiationneeded'));
            }
        };
    },

shimPeerConnection: function(window) {
        var browserDetails = utils.detectBrowser(window);

// The RTCPeerConnection object.
        if (!window.RTCPeerConnection && window.webkitRTCPeerConnection) {
            window.RTCPeerConnection = function(pcConfig, pcConstraints) {
                // Translate iceTransportPolicy to iceTransports,
                // see https://code.google.com/p/webrtc/issues/detail?id=4869
                // this was fixed in M56 along with unprefixing RTCPeerConnection.
                logging('PeerConnection');
                if (pcConfig && pcConfig.iceTransportPolicy) {
                    pcConfig.iceTransports = pcConfig.iceTransportPolicy;
                }

return new window.webkitRTCPeerConnection(pcConfig, pcConstraints);
            };
            window.RTCPeerConnection.prototype =
                window.webkitRTCPeerConnection.prototype;
            // wrap static methods. Currently just generateCertificate.
            if (window.webkitRTCPeerConnection.generateCertificate) {
                Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
                    get: function() {
                        return window.webkitRTCPeerConnection.generateCertificate;
                    }
                });
            }
        } else {
            // migrate from non-spec RTCIceServer.url to RTCIceServer.urls
            var OrigPeerConnection = window.RTCPeerConnection;
            window.RTCPeerConnection = function(pcConfig, pcConstraints) {
                if (pcConfig && pcConfig.iceServers) {
                    var newIceServers = [];
                    for (var i = 0; i < pcConfig.iceServers.length; i++) {
                        var server = pcConfig.iceServers[i];
                        if (!server.hasOwnProperty('urls') &&
                            server.hasOwnProperty('url')) {
                            utils.deprecated('RTCIceServer.url', 'RTCIceServer.urls');
                            server = JSON.parse(JSON.stringify(server));
                            server.urls = server.url;
                            newIceServers.push(server);
                        } else {
                            newIceServers.push(pcConfig.iceServers[i]);
                        }
                    }
                    pcConfig.iceServers = newIceServers;
                }
                return new OrigPeerConnection(pcConfig, pcConstraints);
            };
            window.RTCPeerConnection.prototype = OrigPeerConnection.prototype;
            // wrap static methods. Currently just generateCertificate.
            Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
                get: function() {
                    return OrigPeerConnection.generateCertificate;
                }
            });
        }

var origGetStats = window.RTCPeerConnection.prototype.getStats;
        window.RTCPeerConnection.prototype.getStats = function(selector,
                                                               successCallback, errorCallback) {
            var pc = this;
            var args = arguments;

// If selector is a function then we are in the old style stats so just
            // pass back the original getStats format to avoid breaking old users.
            if (arguments.length > 0 && typeof selector === 'function') {
                return origGetStats.apply(this, arguments);
            }

// When spec-style getStats is supported, return those when called with
            // either no arguments or the selector argument is null.
            if (origGetStats.length === 0 && (arguments.length === 0 ||
                typeof arguments[0] !== 'function')) {
                return origGetStats.apply(this, []);
            }

return standardReport;
            };

// shim getStats with maplike support
            var makeMapStats = function(stats) {
                return new Map(Object.keys(stats).map(function(key) {
                    return [key, stats[key]];
                }));
            };

if (arguments.length >= 2) {
                var successCallbackWrapper_ = function(response) {
                    args[1](makeMapStats(fixChromeStats_(response)));
                };

return origGetStats.apply(this, [successCallbackWrapper_,
                    arguments[0]]);
            }

// promise-support
            return new Promise(function(resolve, reject) {
                origGetStats.apply(pc, [
                    function(response) {
                        resolve(makeMapStats(fixChromeStats_(response)));
                    }, reject]);
            }).then(successCallback, errorCallback);
        };

// add promise support -- natively available in Chrome 51
        if (browserDetails.version < 51) {
            ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
                .forEach(function(method) {
                    var nativeMethod = window.RTCPeerConnection.prototype[method];
                    window.RTCPeerConnection.prototype[method] = function() {
                        var args = arguments;
                        var pc = this;
                        var promise = new Promise(function(resolve, reject) {
                            nativeMethod.apply(pc, [args[0], resolve, reject]);
                        });
                        if (args.length < 2) {
                            return promise;
                        }
                        return promise.then(function() {
                                args[1].apply(null, []);
                            },
                            function(err) {
                                if (args.length >= 3) {
                                    args[2].apply(null, [err]);
                                }
                            });
                    };
                });
        }

// promise support for createOffer and createAnswer. Available (without
        // bugs) since M52: crbug/619289
        if (browserDetails.version < 52) {
            ['createOffer', 'createAnswer'].forEach(function(method) {
                var nativeMethod = window.RTCPeerConnection.prototype[method];
                window.RTCPeerConnection.prototype[method] = function() {
                    var pc = this;
                    if (arguments.length < 1 || (arguments.length === 1 &&
                        typeof arguments[0] === 'object')) {
                        var opts = arguments.length === 1 ? arguments[0] : undefined;
                        return new Promise(function(resolve, reject) {
                            nativeMethod.apply(pc, [resolve, reject, opts]);
                        });
                    }
                    return nativeMethod.apply(this, arguments);
                };
            });
        }

// shim implicit creation of RTCSessionDescription/RTCIceCandidate
        ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
            .forEach(function(method) {
                var nativeMethod = window.RTCPeerConnection.prototype[method];
                window.RTCPeerConnection.prototype[method] = function() {
                    arguments[0] = new ((method === 'addIceCandidate') ?
                        window.RTCIceCandidate :
                        window.RTCSessionDescription)(arguments[0]);
                    return nativeMethod.apply(this, arguments);
                };
            });

// support for addIceCandidate(null or undefined)
        var nativeAddIceCandidate =
            window.RTCPeerConnection.prototype.addIceCandidate;
        window.RTCPeerConnection.prototype.addIceCandidate = function() {
            if (!arguments[0]) {
                if (arguments[1]) {
                    arguments[1].apply(null);
                }
                return Promise.resolve();
            }
            return nativeAddIceCandidate.apply(this, arguments);
        };
    }
};

},{"../utils.js":13,"./getusermedia":6}],6:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';
var utils = require('../utils.js');
var logging = utils.log;

// Expose public methods.
module.exports = function(window) {
    var browserDetails = utils.detectBrowser(window);
    var navigator = window && window.navigator;

if ((face && (face.exact === 'user' || face.exact === 'environment' ||
                face.ideal === 'user' || face.ideal === 'environment')) &&
                !(navigator.mediaDevices.getSupportedConstraints &&
                    navigator.mediaDevices.getSupportedConstraints().facingMode &&
                    !getSupportedFacingModeLies)) {
                delete constraints.video.facingMode;
                var matches;
                if (face.exact === 'environment' || face.ideal === 'environment') {
                    matches = ['back', 'rear'];
                } else if (face.exact === 'user' || face.ideal === 'user') {
                    matches = ['front'];
                }
                if (matches) {
                    // Look for matches in label, or use last cam for back (typical).
                    return navigator.mediaDevices.enumerateDevices()
                        .then(function(devices) {
                            devices = devices.filter(function(d) {
                                return d.kind === 'videoinput';
                            });
                            var dev = devices.find(function(d) {
                                return matches.some(function(match) {
                                    return d.label.toLowerCase().indexOf(match) !== -1;
                                });
                            });
                            if (!dev && devices.length && matches.indexOf('back') !== -1) {
                                dev = devices[devices.length - 1]; // more likely the back cam
                            }
                            if (dev) {
                                constraints.video.deviceId = face.exact ? {exact: dev.deviceId} :
                                    {ideal: dev.deviceId};
                            }
                            constraints.video = constraintsToChrome_(constraints.video);
                            logging('chrome: ' + JSON.stringify(constraints));
                            return func(constraints);
                        });
                }
            }
            constraints.video = constraintsToChrome_(constraints.video);
        }
        logging('chrome: ' + JSON.stringify(constraints));
        return func(constraints);
    };

navigator.getUserMedia = getUserMedia_;

// Returns the result of getUserMedia as a Promise.
    var getUserMediaPromise_ = function(constraints) {
        return new Promise(function(resolve, reject) {
            navigator.getUserMedia(constraints, resolve, reject);
        });
    };

if (!navigator.mediaDevices) {
        navigator.mediaDevices = {
            getUserMedia: getUserMediaPromise_,
            enumerateDevices: function() {
                return new Promise(function(resolve) {
                    var kinds = {audio: 'audioinput', video: 'videoinput'};
                    return window.MediaStreamTrack.getSources(function(devices) {
                        resolve(devices.map(function(device) {
                            return {label: device.label,
                                kind: kinds[device.kind],
                                deviceId: device.id,
                                groupId: ''};
                        }));
                    });
                });
            },
            getSupportedConstraints: function() {
                return {
                    deviceId: true, echoCancellation: true, facingMode: true,
                    frameRate: true, height: true, width: true
                };
            }
        };
    }

// A shim for getUserMedia method on the mediaDevices object.
    // TODO(KaptenJansson) remove once implemented in Chrome stable.
    if (!navigator.mediaDevices.getUserMedia) {
        navigator.mediaDevices.getUserMedia = function(constraints) {
            return getUserMediaPromise_(constraints);
        };
    } else {
        // Even though Chrome 45 has navigator.mediaDevices and a getUserMedia
        // function which returns a Promise, it does not accept spec-style
        // constraints.
        var origGetUserMedia = navigator.mediaDevices.getUserMedia.
        bind(navigator.mediaDevices);
        navigator.mediaDevices.getUserMedia = function(cs) {
            return shimConstraints_(cs, function(c) {
                return origGetUserMedia(c).then(function(stream) {
                    if (c.audio && !stream.getAudioTracks().length ||
                        c.video && !stream.getVideoTracks().length) {
                        stream.getTracks().forEach(function(track) {
                            track.stop();
                        });
                        throw new DOMException('', 'NotFoundError');
                    }
                    return stream;
                }, function(e) {
                    return Promise.reject(shimError_(e));
                });
            });
        };
    }

// Dummy devicechange event methods.
    // TODO(KaptenJansson) remove once implemented in Chrome stable.
    if (typeof navigator.mediaDevices.addEventListener === 'undefined') {
        navigator.mediaDevices.addEventListener = function() {
            logging('Dummy mediaDevices.addEventListener called.');
        };
    }
    if (typeof navigator.mediaDevices.removeEventListener === 'undefined') {
        navigator.mediaDevices.removeEventListener = function() {
            logging('Dummy mediaDevices.removeEventListener called.');
        };
    }
};

},{"../utils.js":13}],7:[function(require,module,exports){
/*
*  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';

var SDPUtils = require('sdp');
var utils = require('./utils');

module.exports = {
    shimRTCIceCandidate: function(window) {
        // foundation is arbitrarily chosen as an indicator for full support for
        // https://w3c.github.io/webrtc-pc/#rtcicecandidate-interface
        if (!window.RTCIceCandidate || (window.RTCIceCandidate && 'foundation' in
            window.RTCIceCandidate.prototype)) {
            return;
        }

var NativeRTCIceCandidate = window.RTCIceCandidate;
        window.RTCIceCandidate = function(args) {
            // Remove the a= which shouldn't be part of the candidate string.
            if (typeof args === 'object' && args.candidate &&
                args.candidate.indexOf('a=') === 0) {
                args = JSON.parse(JSON.stringify(args));
                args.candidate = args.candidate.substr(2);
            }

if (args.candidate && args.candidate.length) {
                // Augment the native candidate with the parsed fields.
                var nativeCandidate = new NativeRTCIceCandidate(args);
                var parsedCandidate = SDPUtils.parseCandidate(args.candidate);
                var augmentedCandidate = Object.assign(nativeCandidate,
                    parsedCandidate);

// Add a serializer that does not serialize the extra attributes.
                augmentedCandidate.toJSON = function() {
                    return {
                        candidate: augmentedCandidate.candidate,
                        sdpMid: augmentedCandidate.sdpMid,
                        sdpMLineIndex: augmentedCandidate.sdpMLineIndex,
                        usernameFragment: augmentedCandidate.usernameFragment,
                    };
                };
                return augmentedCandidate;
            }
            return new NativeRTCIceCandidate(args);
        };
        window.RTCIceCandidate.prototype = NativeRTCIceCandidate.prototype;

// Hook up the augmented candidate in onicecandidate and
        // addEventListener('icecandidate', ...)
        utils.wrapPeerConnectionEvent(window, 'icecandidate', function(e) {
            if (e.candidate) {
                Object.defineProperty(e, 'candidate', {
                    value: new window.RTCIceCandidate(e.candidate),
                    writable: 'false'
                });
            }
            return e;
        });
    },

// shimCreateObjectURL must be called before shimSourceObject to avoid loop.

shimCreateObjectURL: function(window) {
        var URL = window && window.URL;

if (!(typeof window === 'object' && window.HTMLMediaElement &&
            'srcObject' in window.HTMLMediaElement.prototype &&
            URL.createObjectURL && URL.revokeObjectURL)) {
            // Only shim CreateObjectURL using srcObject if srcObject exists.
            return undefined;
        }

var nativeCreateObjectURL = URL.createObjectURL.bind(URL);
        var nativeRevokeObjectURL = URL.revokeObjectURL.bind(URL);
        var streams = new Map(), newId = 0;

URL.createObjectURL = function(stream) {
            if ('getTracks' in stream) {
                var url = 'polyblob:' + (++newId);
                streams.set(url, stream);
                utils.deprecated('URL.createObjectURL(stream)',
                    'elem.srcObject = stream');
                return url;
            }
            return nativeCreateObjectURL(stream);
        };
        URL.revokeObjectURL = function(url) {
            nativeRevokeObjectURL(url);
            streams.delete(url);
        };

var nativeSetAttribute = window.HTMLMediaElement.prototype.setAttribute;
        window.HTMLMediaElement.prototype.setAttribute = function() {
            if (arguments.length === 2 &&
                ('' + arguments[0]).toLowerCase() === 'src') {
                this.srcObject = streams.get(arguments[1]) || null;
            }
            return nativeSetAttribute.apply(this, arguments);
        };
    },

shimMaxMessageSize: function(window) {
        if (window.RTCSctpTransport || !window.RTCPeerConnection) {
            return;
        }
        var browserDetails = utils.detectBrowser(window);

if (!('sctp' in window.RTCPeerConnection.prototype)) {
            Object.defineProperty(window.RTCPeerConnection.prototype, 'sctp', {
                get: function() {
                    return typeof this._sctp === 'undefined' ? null : this._sctp;
                }
            });
        }

var sctpInDescription = function(description) {
            var sections = SDPUtils.splitSections(description.sdp);
            sections.shift();
            return sections.some(function(mediaSection) {
                var mLine = SDPUtils.parseMLine(mediaSection);
                return mLine && mLine.kind === 'application'
                    && mLine.protocol.indexOf('SCTP') !== -1;
            });
        };

var getRemoteFirefoxVersion = function(description) {
            // TODO: Is there a better solution for detecting Firefox?
            var match = description.sdp.match(/mozilla...THIS_IS_SDPARTA-(\d+)/);
            if (match === null || match.length < 2) {
                return -1;
            }
            var version = parseInt(match[1], 10);
            // Test for NaN (yes, this is ugly)
            return version !== version ? -1 : version;
        };

var getMaxMessageSize = function(description, remoteIsFirefox) {
            // Note: 65536 bytes is the default value from the SDP spec. Also,
            //       every implementation we know supports receiving 65536 bytes.
            var maxMessageSize = 65536;

// FF 57 has a slightly incorrect default remote max message size, so
            // we need to adjust it here to avoid a failure when sending.
            // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1425697
            if (browserDetails.browser === 'firefox'
                && browserDetails.version === 57) {
                maxMessageSize = 65535;
            }

var match = SDPUtils.matchPrefix(description.sdp, 'a=max-message-size:');
            if (match.length > 0) {
                maxMessageSize = parseInt(match[0].substr(19), 10);
            } else if (browserDetails.browser === 'firefox' &&
                remoteIsFirefox !== -1) {
                // If the maximum message size is not present in the remote SDP and
                // both local and remote are Firefox, the remote peer can receive
                // ~2 GiB.
                maxMessageSize = 2147483637;
            }
            return maxMessageSize;
        };

var origSetRemoteDescription =
            window.RTCPeerConnection.prototype.setRemoteDescription;
        window.RTCPeerConnection.prototype.setRemoteDescription = function() {
            var pc = this;
            pc._sctp = null;

if (sctpInDescription(arguments[0])) {
                // Check if the remote is FF.
                var isFirefox = getRemoteFirefoxVersion(arguments[0]);

// Get the maximum message size the local peer is capable of sending
                var canSendMMS = getCanSendMaxMessageSize(isFirefox);

// Get the maximum message size of the remote peer.
                var remoteMMS = getMaxMessageSize(arguments[0], isFirefox);

// Determine final maximum message size
                var maxMessageSize;
                if (canSendMMS === 0 && remoteMMS === 0) {
                    maxMessageSize = Number.POSITIVE_INFINITY;
                } else if (canSendMMS === 0 || remoteMMS === 0) {
                    maxMessageSize = Math.max(canSendMMS, remoteMMS);
                } else {
                    maxMessageSize = Math.min(canSendMMS, remoteMMS);
                }

// Create a dummy RTCSctpTransport object and the 'maxMessageSize'
                // attribute.
                var sctp = {};
                Object.defineProperty(sctp, 'maxMessageSize', {
                    get: function() {
                        return maxMessageSize;
                    }
                });
                pc._sctp = sctp;
            }

return origSetRemoteDescription.apply(pc, arguments);
        };
    },

shimSendThrowTypeError: function(window) {
        if (!(window.RTCPeerConnection &&
            'createDataChannel' in window.RTCPeerConnection.prototype)) {
            return;
        }

// Note: Although Firefox >= 57 has a native implementation, the maximum
        //       message size can be reset for all data channels at a later stage.
        //       See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831

var origCreateDataChannel =
            window.RTCPeerConnection.prototype.createDataChannel;
        window.RTCPeerConnection.prototype.createDataChannel = function() {
            var pc = this;
            var dataChannel = origCreateDataChannel.apply(pc, arguments);
            var origDataChannelSend = dataChannel.send;

// Patch 'send' method
            dataChannel.send = function() {
                var dc = this;
                var data = arguments[0];
                var length = data.length || data.size || data.byteLength;
                if (length > pc.sctp.maxMessageSize) {
                    throw new DOMException('Message too large (can send a maximum of ' +
                        pc.sctp.maxMessageSize + ' bytes)', 'TypeError');
                }
                return origDataChannelSend.apply(dc, arguments);
            };

return dataChannel;
        };
    }
};

},{"./utils":13,"sdp":2}],8:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';

var utils = require('../utils');
var shimRTCPeerConnection = require('rtcpeerconnection-shim');

module.exports = {
    shimGetUserMedia: require('./getusermedia'),
    shimPeerConnection: function(window) {
        var browserDetails = utils.detectBrowser(window);

if (window.RTCIceGatherer) {
            if (!window.RTCIceCandidate) {
                window.RTCIceCandidate = function(args) {
                    return args;
                };
            }
            if (!window.RTCSessionDescription) {
                window.RTCSessionDescription = function(args) {
                    return args;
                };
            }
            // this adds an additional event listener to MediaStrackTrack that signals
            // when a tracks enabled property was changed. Workaround for a bug in
            // addStream, see below. No longer required in 15025+
            if (browserDetails.version < 15025) {
                var origMSTEnabled = Object.getOwnPropertyDescriptor(
                    window.MediaStreamTrack.prototype, 'enabled');
                Object.defineProperty(window.MediaStreamTrack.prototype, 'enabled', {
                    set: function(value) {
                        origMSTEnabled.set.call(this, value);
                        var ev = new Event('enabled');
                        ev.enabled = value;
                        this.dispatchEvent(ev);
                    }
                });
            }
        }

// ORTC defines the DTMF sender a bit different.
        // https://github.com/w3c/ortc/issues/714
        if (window.RTCRtpSender && !('dtmf' in window.RTCRtpSender.prototype)) {
            Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
                get: function() {
                    if (this._dtmf === undefined) {
                        if (this.track.kind === 'audio') {
                            this._dtmf = new window.RTCDtmfSender(this);
                        } else if (this.track.kind === 'video') {
                            this._dtmf = null;
                        }
                    }
                    return this._dtmf;
                }
            });
        }
        // Edge currently only implements the RTCDtmfSender, not the
        // RTCDTMFSender alias. See http://draft.ortc.org/#rtcdtmfsender2*
        if (window.RTCDtmfSender && !window.RTCDTMFSender) {
            window.RTCDTMFSender = window.RTCDtmfSender;
        }

window.RTCPeerConnection =
            shimRTCPeerConnection(window, browserDetails.version);
    },
    shimReplaceTrack: function(window) {
        // ORTC has replaceTrack -- https://github.com/w3c/ortc/issues/614
        if (window.RTCRtpSender &&
            !('replaceTrack' in window.RTCRtpSender.prototype)) {
            window.RTCRtpSender.prototype.replaceTrack =
                window.RTCRtpSender.prototype.setTrack;
        }
    }
};

},{"../utils":13,"./getusermedia":9,"rtcpeerconnection-shim":1}],9:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';

// Expose public methods.
module.exports = function(window) {
    var navigator = window && window.navigator;

// getUserMedia error shim.
    var origGetUserMedia = navigator.mediaDevices.getUserMedia.
    bind(navigator.mediaDevices);
    navigator.mediaDevices.getUserMedia = function(c) {
        return origGetUserMedia(c).catch(function(e) {
            return Promise.reject(shimError_(e));
        });
    };
};

},{}],10:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';

var utils = require('../utils');

module.exports = {
    shimGetUserMedia: require('./getusermedia'),
    shimOnTrack: function(window) {
        if (typeof window === 'object' && window.RTCPeerConnection && !('ontrack' in
            window.RTCPeerConnection.prototype)) {
            Object.defineProperty(window.RTCPeerConnection.prototype, 'ontrack', {
                get: function() {
                    return this._ontrack;
                },
                set: function(f) {
                    if (this._ontrack) {
                        this.removeEventListener('track', this._ontrack);
                        this.removeEventListener('addstream', this._ontrackpoly);
                    }
                    this.addEventListener('track', this._ontrack = f);
                    this.addEventListener('addstream', this._ontrackpoly = function(e) {
                        e.stream.getTracks().forEach(function(track) {
                            var event = new Event('track');
                            event.track = track;
                            event.receiver = {track: track};
                            event.transceiver = {receiver: event.receiver};
                            event.streams = [e.stream];
                            this.dispatchEvent(event);
                        }.bind(this));
                    }.bind(this));
                }
            });
        }
        if (typeof window === 'object' && window.RTCTrackEvent &&
            ('receiver' in window.RTCTrackEvent.prototype) &&
            !('transceiver' in window.RTCTrackEvent.prototype)) {
            Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
                get: function() {
                    return {receiver: this.receiver};
                }
            });
        }
    },

shimSourceObject: function(window) {
        // Firefox has supported mozSrcObject since FF22, unprefixed in 42.
        if (typeof window === 'object') {
            if (window.HTMLMediaElement &&
                !('srcObject' in window.HTMLMediaElement.prototype)) {
                // Shim the srcObject property, once, when HTMLMediaElement is found.
                Object.defineProperty(window.HTMLMediaElement.prototype, 'srcObject', {
                    get: function() {
                        return this.mozSrcObject;
                    },
                    set: function(stream) {
                        this.mozSrcObject = stream;
                    }
                });
            }
        }
    },

shimPeerConnection: function(window) {
        var browserDetails = utils.detectBrowser(window);

if (typeof window !== 'object' || !(window.RTCPeerConnection ||
            window.mozRTCPeerConnection)) {
            return; // probably media.peerconnection.enabled=false in about:config
        }
        // The RTCPeerConnection object.
        if (!window.RTCPeerConnection) {
            window.RTCPeerConnection = function(pcConfig, pcConstraints) {
                if (browserDetails.version < 38) {
                    // .urls is not supported in FF < 38.
                    // create RTCIceServers with a single url.
                    if (pcConfig && pcConfig.iceServers) {
                        var newIceServers = [];
                        for (var i = 0; i < pcConfig.iceServers.length; i++) {
                            var server = pcConfig.iceServers[i];
                            if (server.hasOwnProperty('urls')) {
                                for (var j = 0; j < server.urls.length; j++) {
                                    var newServer = {
                                        url: server.urls[j]
                                    };
                                    if (server.urls[j].indexOf('turn') === 0) {
                                        newServer.username = server.username;
                                        newServer.credential = server.credential;
                                    }
                                    newIceServers.push(newServer);
                                }
                            } else {
                                newIceServers.push(pcConfig.iceServers[i]);
                            }
                        }
                        pcConfig.iceServers = newIceServers;
                    }
                }
                return new window.mozRTCPeerConnection(pcConfig, pcConstraints);
            };
            window.RTCPeerConnection.prototype =
                window.mozRTCPeerConnection.prototype;

// wrap static methods. Currently just generateCertificate.
            if (window.mozRTCPeerConnection.generateCertificate) {
                Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
                    get: function() {
                        return window.mozRTCPeerConnection.generateCertificate;
                    }
                });
            }

window.RTCSessionDescription = window.mozRTCSessionDescription;
            window.RTCIceCandidate = window.mozRTCIceCandidate;
        }

// shim away need for obsolete RTCIceCandidate/RTCSessionDescription.
        ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
            .forEach(function(method) {
                var nativeMethod = window.RTCPeerConnection.prototype[method];
                window.RTCPeerConnection.prototype[method] = function() {
                    arguments[0] = new ((method === 'addIceCandidate') ?
                        window.RTCIceCandidate :
                        window.RTCSessionDescription)(arguments[0]);
                    return nativeMethod.apply(this, arguments);
                };
            });

// shim getStats with maplike support
        var makeMapStats = function(stats) {
            var map = new Map();
            Object.keys(stats).forEach(function(key) {
                map.set(key, stats[key]);
                map[key] = stats[key];
            });
            return map;
        };

var modernStatsTypes = {
            inboundrtp: 'inbound-rtp',
            outboundrtp: 'outbound-rtp',
            candidatepair: 'candidate-pair',
            localcandidate: 'local-candidate',
            remotecandidate: 'remote-candidate'
        };

shimRemoveStream: function(window) {
        if (!window.RTCPeerConnection ||
            'removeStream' in window.RTCPeerConnection.prototype) {
            return;
        }
        window.RTCPeerConnection.prototype.removeStream = function(stream) {
            var pc = this;
            utils.deprecated('removeStream', 'removeTrack');
            this.getSenders().forEach(function(sender) {
                if (sender.track && stream.getTracks().indexOf(sender.track) !== -1) {
                    pc.removeTrack(sender);
                }
            });
        };
    }
};

},{"../utils":13,"./getusermedia":11}],11:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';

var utils = require('../utils');
var logging = utils.log;

// Expose public methods.
module.exports = function(window) {
    var browserDetails = utils.detectBrowser(window);
    var navigator = window && window.navigator;
    var MediaStreamTrack = window && window.MediaStreamTrack;

// getUserMedia constraints shim.
    var getUserMedia_ = function(constraints, onSuccess, onError) {
        var constraintsToFF37_ = function(c) {
            if (typeof c !== 'object' || c.require) {
                return c;
            }
            var require = [];
            Object.keys(c).forEach(function(key) {
                if (key === 'require' || key === 'advanced' || key === 'mediaSource') {
                    return;
                }
                var r = c[key] = (typeof c[key] === 'object') ?
                    c[key] : {ideal: c[key]};
                if (r.min !== undefined ||
                    r.max !== undefined || r.exact !== undefined) {
                    require.push(key);
                }
                if (r.exact !== undefined) {
                    if (typeof r.exact === 'number') {
                        r. min = r.max = r.exact;
                    } else {
                        c[key] = r.exact;
                    }
                    delete r.exact;
                }
                if (r.ideal !== undefined) {
                    c.advanced = c.advanced || [];
                    var oc = {};
                    if (typeof r.ideal === 'number') {
                        oc[key] = {min: r.ideal, max: r.ideal};
                    } else {
                        oc[key] = r.ideal;
                    }
                    c.advanced.push(oc);
                    delete r.ideal;
                    if (!Object.keys(r).length) {
                        delete c[key];
                    }
                }
            });
            if (require.length) {
                c.require = require;
            }
            return c;
        };
        constraints = JSON.parse(JSON.stringify(constraints));
        if (browserDetails.version < 38) {
            logging('spec: ' + JSON.stringify(constraints));
            if (constraints.audio) {
                constraints.audio = constraintsToFF37_(constraints.audio);
            }
            if (constraints.video) {
                constraints.video = constraintsToFF37_(constraints.video);
            }
            logging('ff37: ' + JSON.stringify(constraints));
        }
        return navigator.mozGetUserMedia(constraints, onSuccess, function(e) {
            onError(shimError_(e));
        });
    };

// Returns the result of getUserMedia as a Promise.
    var getUserMediaPromise_ = function(constraints) {
        return new Promise(function(resolve, reject) {
            getUserMedia_(constraints, resolve, reject);
        });
    };

// Shim for mediaDevices on older versions.
    if (!navigator.mediaDevices) {
        navigator.mediaDevices = {getUserMedia: getUserMediaPromise_,
            addEventListener: function() { },
            removeEventListener: function() { }
        };
    }
    navigator.mediaDevices.enumerateDevices =
        navigator.mediaDevices.enumerateDevices || function() {
            return new Promise(function(resolve) {
                var infos = [
                    {kind: 'audioinput', deviceId: 'default', label: '', groupId: ''},
                    {kind: 'videoinput', deviceId: 'default', label: '', groupId: ''}
                ];
                resolve(infos);
            });
        };

if (browserDetails.version < 41) {
        // Work around http://bugzil.la/1169665
        var orgEnumerateDevices =
            navigator.mediaDevices.enumerateDevices.bind(navigator.mediaDevices);
        navigator.mediaDevices.enumerateDevices = function() {
            return orgEnumerateDevices().then(undefined, function(e) {
                if (e.name === 'NotFoundError') {
                    return [];
                }
                throw e;
            });
        };
    }
    if (browserDetails.version < 49) {
        var origGetUserMedia = navigator.mediaDevices.getUserMedia.
        bind(navigator.mediaDevices);
        navigator.mediaDevices.getUserMedia = function(c) {
            return origGetUserMedia(c).then(function(stream) {
                // Work around https://bugzil.la/802326
                if (c.audio && !stream.getAudioTracks().length ||
                    c.video && !stream.getVideoTracks().length) {
                    stream.getTracks().forEach(function(track) {
                        track.stop();
                    });
                    throw new DOMException('The object can not be found here.',
                        'NotFoundError');
                }
                return stream;
            }, function(e) {
                return Promise.reject(shimError_(e));
            });
        };
    }
    if (!(browserDetails.version > 55 &&
        'autoGainControl' in navigator.mediaDevices.getSupportedConstraints())) {
        var remap = function(obj, a, b) {
            if (a in obj && !(b in obj)) {
                obj[b] = obj[a];
                delete obj[a];
            }
        };

var nativeGetUserMedia = navigator.mediaDevices.getUserMedia.
        bind(navigator.mediaDevices);
        navigator.mediaDevices.getUserMedia = function(c) {
            if (typeof c === 'object' && typeof c.audio === 'object') {
                c = JSON.parse(JSON.stringify(c));
                remap(c.audio, 'autoGainControl', 'mozAutoGainControl');
                remap(c.audio, 'noiseSuppression', 'mozNoiseSuppression');
            }
            return nativeGetUserMedia(c);
        };

if (MediaStreamTrack && MediaStreamTrack.prototype.getSettings) {
            var nativeGetSettings = MediaStreamTrack.prototype.getSettings;
            MediaStreamTrack.prototype.getSettings = function() {
                var obj = nativeGetSettings.apply(this, arguments);
                remap(obj, 'mozAutoGainControl', 'autoGainControl');
                remap(obj, 'mozNoiseSuppression', 'noiseSuppression');
                return obj;
            };
        }

if (MediaStreamTrack && MediaStreamTrack.prototype.applyConstraints) {
            var nativeApplyConstraints = MediaStreamTrack.prototype.applyConstraints;
            MediaStreamTrack.prototype.applyConstraints = function(c) {
                if (this.kind === 'audio' && typeof c === 'object') {
                    c = JSON.parse(JSON.stringify(c));
                    remap(c, 'autoGainControl', 'mozAutoGainControl');
                    remap(c, 'noiseSuppression', 'mozNoiseSuppression');
                }
                return nativeApplyConstraints.apply(this, [c]);
            };
        }
    }
    navigator.getUserMedia = function(constraints, onSuccess, onError) {
        if (browserDetails.version < 44) {
            return getUserMedia_(constraints, onSuccess, onError);
        }
        // Replace Firefox 44+'s deprecation warning with unprefixed version.
        utils.deprecated('navigator.getUserMedia',
            'navigator.mediaDevices.getUserMedia');
        navigator.mediaDevices.getUserMedia(constraints).then(onSuccess, onError);
    };
};

},{"../utils":13}],12:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
'use strict';
var utils = require('../utils');

module.exports = {
    shimLocalStreamsAPI: function(window) {
        if (typeof window !== 'object' || !window.RTCPeerConnection) {
            return;
        }
        if (!('getLocalStreams' in window.RTCPeerConnection.prototype)) {
            window.RTCPeerConnection.prototype.getLocalStreams = function() {
                if (!this._localStreams) {
                    this._localStreams = [];
                }
                return this._localStreams;
            };
        }
        if (!('getStreamById' in window.RTCPeerConnection.prototype)) {
            window.RTCPeerConnection.prototype.getStreamById = function(id) {
                var result = null;
                if (this._localStreams) {
                    this._localStreams.forEach(function(stream) {
                        if (stream.id === id) {
                            result = stream;
                        }
                    });
                }
                if (this._remoteStreams) {
                    this._remoteStreams.forEach(function(stream) {
                        if (stream.id === id) {
                            result = stream;
                        }
                    });
                }
                return result;
            };
        }
        if (!('addStream' in window.RTCPeerConnection.prototype)) {
            var _addTrack = window.RTCPeerConnection.prototype.addTrack;
            window.RTCPeerConnection.prototype.addStream = function(stream) {
                if (!this._localStreams) {
                    this._localStreams = [];
                }
                if (this._localStreams.indexOf(stream) === -1) {
                    this._localStreams.push(stream);
                }
                var pc = this;
                stream.getTracks().forEach(function(track) {
                    _addTrack.call(pc, track, stream);
                });
            };

prototype.createOffer = function(successCallback, failureCallback) {
            var options = (arguments.length >= 2) ? arguments[2] : arguments[0];
            var promise = createOffer.apply(this, [options]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };

prototype.createAnswer = function(successCallback, failureCallback) {
            var options = (arguments.length >= 2) ? arguments[2] : arguments[0];
            var promise = createAnswer.apply(this, [options]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };

var withCallback = function(description, successCallback, failureCallback) {
            var promise = setLocalDescription.apply(this, [description]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };
        prototype.setLocalDescription = withCallback;

withCallback = function(description, successCallback, failureCallback) {
            var promise = setRemoteDescription.apply(this, [description]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };
        prototype.setRemoteDescription = withCallback;

withCallback = function(candidate, successCallback, failureCallback) {
            var promise = addIceCandidate.apply(this, [candidate]);
            if (!failureCallback) {
                return promise;
            }
            promise.then(successCallback, failureCallback);
            return Promise.resolve();
        };
        prototype.addIceCandidate = withCallback;
    },
    shimGetUserMedia: function(window) {
        var navigator = window && window.navigator;

if (!navigator.getUserMedia) {
            if (navigator.webkitGetUserMedia) {
                navigator.getUserMedia = navigator.webkitGetUserMedia.bind(navigator);
            } else if (navigator.mediaDevices &&
                navigator.mediaDevices.getUserMedia) {
                navigator.getUserMedia = function(constraints, cb, errcb) {
                    navigator.mediaDevices.getUserMedia(constraints)
                        .then(cb, errcb);
                }.bind(navigator);
            }
        }
    },
    shimRTCIceServerUrls: function(window) {
        // migrate from non-spec RTCIceServer.url to RTCIceServer.urls
        var OrigPeerConnection = window.RTCPeerConnection;
        window.RTCPeerConnection = function(pcConfig, pcConstraints) {
            if (pcConfig && pcConfig.iceServers) {
                var newIceServers = [];
                for (var i = 0; i < pcConfig.iceServers.length; i++) {
                    var server = pcConfig.iceServers[i];
                    if (!server.hasOwnProperty('urls') &&
                        server.hasOwnProperty('url')) {
                        utils.deprecated('RTCIceServer.url', 'RTCIceServer.urls');
                        server = JSON.parse(JSON.stringify(server));
                        server.urls = server.url;
                        delete server.url;
                        newIceServers.push(server);
                    } else {
                        newIceServers.push(pcConfig.iceServers[i]);
                    }
                }
                pcConfig.iceServers = newIceServers;
            }
            return new OrigPeerConnection(pcConfig, pcConstraints);
        };
        window.RTCPeerConnection.prototype = OrigPeerConnection.prototype;
        // wrap static methods. Currently just generateCertificate.
        if ('generateCertificate' in window.RTCPeerConnection) {
            Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
                get: function() {
                    return OrigPeerConnection.generateCertificate;
                }
            });
        }
    },
    shimTrackEventTransceiver: function(window) {
        // Add event.transceiver member over deprecated event.receiver
        if (typeof window === 'object' && window.RTCPeerConnection &&
            ('receiver' in window.RTCTrackEvent.prototype) &&
            // can't check 'transceiver' in window.RTCTrackEvent.prototype, as it is
            // defined for some reason even when window.RTCTransceiver is not.
            !window.RTCTransceiver) {
            Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
                get: function() {
                    return {receiver: this.receiver};
                }
            });
        }
    },

shimCreateOfferLegacy: function(window) {
        var origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
        window.RTCPeerConnection.prototype.createOffer = function(offerOptions) {
            var pc = this;
            if (offerOptions) {
                if (typeof offerOptions.offerToReceiveAudio !== 'undefined') {
                    // support bit values
                    offerOptions.offerToReceiveAudio = !!offerOptions.offerToReceiveAudio;
                }
                var audioTransceiver = pc.getTransceivers().find(function(transceiver) {
                    return transceiver.sender.track &&
                        transceiver.sender.track.kind === 'audio';
                });
                if (offerOptions.offerToReceiveAudio === false && audioTransceiver) {
                    if (audioTransceiver.direction === 'sendrecv') {
                        if (audioTransceiver.setDirection) {
                            audioTransceiver.setDirection('sendonly');
                        } else {
                            audioTransceiver.direction = 'sendonly';
                        }
                    } else if (audioTransceiver.direction === 'recvonly') {
                        if (audioTransceiver.setDirection) {
                            audioTransceiver.setDirection('inactive');
                        } else {
                            audioTransceiver.direction = 'inactive';
                        }
                    }
                } else if (offerOptions.offerToReceiveAudio === true &&
                    !audioTransceiver) {
                    pc.addTransceiver('audio');
                }

if (typeof offerOptions.offerToReceiveAudio !== 'undefined') {
                    // support bit values
                    offerOptions.offerToReceiveVideo = !!offerOptions.offerToReceiveVideo;
                }
                var videoTransceiver = pc.getTransceivers().find(function(transceiver) {
                    return transceiver.sender.track &&
                        transceiver.sender.track.kind === 'video';
                });
                if (offerOptions.offerToReceiveVideo === false && videoTransceiver) {
                    if (videoTransceiver.direction === 'sendrecv') {
                        videoTransceiver.setDirection('sendonly');
                    } else if (videoTransceiver.direction === 'recvonly') {
                        videoTransceiver.setDirection('inactive');
                    }
                } else if (offerOptions.offerToReceiveVideo === true &&
                    !videoTransceiver) {
                    pc.addTransceiver('video');
                }
            }
            return origCreateOffer.apply(pc, arguments);
        };
    }
};

},{"../utils":13}],13:[function(require,module,exports){
/*
*  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
*  Use of this source code is governed by a BSD-style license
*  that can be found in the LICENSE file in the root of the source
*  tree.
*/
/* eslint-env node */
'use strict';

var logDisabled_ = true;
var deprecationWarnings_ = true;

/**
 * Extract browser version out of the provided user agent string.
 *
 * @param {!string} uastring userAgent string.
 * @param {!string} expr Regular expression used as match criteria.
 * @param {!number} pos position in the version string to be returned.
 * @return {!number} browser version.
 */
function extractVersion(uastring, expr, pos) {
    var match = uastring.match(expr);
    return match && match.length >= pos && parseInt(match[pos], 10);
}

// Wraps the peerconnection event eventNameToWrap in a function
// which returns the modified event object.
function wrapPeerConnectionEvent(window, eventNameToWrap, wrapper) {
    if (!window.RTCPeerConnection) {
        return;
    }
    var proto = window.RTCPeerConnection.prototype;
    var nativeAddEventListener = proto.addEventListener;
    proto.addEventListener = function(nativeEventName, cb) {
        if (nativeEventName !== eventNameToWrap) {
            return nativeAddEventListener.apply(this, arguments);
        }
        var wrappedCallback = function(e) {
            cb(wrapper(e));
        };
        this._eventMap = this._eventMap || {};
        this._eventMap[cb] = wrappedCallback;
        return nativeAddEventListener.apply(this, [nativeEventName,
            wrappedCallback]);
    };

var nativeRemoveEventListener = proto.removeEventListener;
    proto.removeEventListener = function(nativeEventName, cb) {
        if (nativeEventName !== eventNameToWrap || !this._eventMap
            || !this._eventMap[cb]) {
            return nativeRemoveEventListener.apply(this, arguments);
        }
        var unwrappedCb = this._eventMap[cb];
        delete this._eventMap[cb];
        return nativeRemoveEventListener.apply(this, [nativeEventName,
            unwrappedCb]);
    };

Object.defineProperty(proto, 'on' + eventNameToWrap, {
        get: function() {
            return this['_on' + eventNameToWrap];
        },
        set: function(cb) {
            if (this['_on' + eventNameToWrap]) {
                this.removeEventListener(eventNameToWrap,
                    this['_on' + eventNameToWrap]);
                delete this['_on' + eventNameToWrap];
            }
            if (cb) {
                this.addEventListener(eventNameToWrap,
                    this['_on' + eventNameToWrap] = cb);
            }
        }
    });
}

// Utility methods.
module.exports = {
    extractVersion: extractVersion,
    wrapPeerConnectionEvent: wrapPeerConnectionEvent,
    disableLog: function(bool) {
        if (typeof bool !== 'boolean') {
            return new Error('Argument type: ' + typeof bool +
                '. Please use a boolean.');
        }
        logDisabled_ = bool;
        return (bool) ? 'adapter.js logging disabled' :
            'adapter.js logging enabled';
    },

/**
     * Disable or enable deprecation warnings
     * @param {!boolean} bool set to true to disable warnings.
     */
    disableWarnings: function(bool) {
        if (typeof bool !== 'boolean') {
            return new Error('Argument type: ' + typeof bool +
                '. Please use a boolean.');
        }
        deprecationWarnings_ = !bool;
        return 'adapter.js deprecation warnings ' + (bool ? 'disabled' : 'enabled');
    },

log: function() {
        if (typeof window === 'object') {
            if (logDisabled_) {
                return;
            }
            if (typeof console !== 'undefined' && typeof console.log === 'function') {
                console.log.apply(console, arguments);
            }
        }
    },

/**
     * Shows a deprecation warning suggesting the modern and spec-compatible API.
     */
    deprecated: function(oldMethod, newMethod) {
        if (!deprecationWarnings_) {
            return;
        }
        console.warn(oldMethod + ' is deprecated, please use ' + newMethod +
            ' instead.');
    },

/**
     * Browser detector.
     *
     * @return {object} result containing browser and version
     *     properties.
     */
    detectBrowser: function(window) {
        var navigator = window && window.navigator;

// Returned result object.
        var result = {};
        result.browser = null;
        result.version = null;

// Fail early if it's not a browser
        if (typeof window === 'undefined' || !window.navigator) {
            result.browser = 'Not a browser.';
            return result;
        }

if (navigator.mozGetUserMedia) { // Firefox.
            result.browser = 'firefox';
            result.version = extractVersion(navigator.userAgent,
                /Firefox\/(\d+)\./, 1);
        } else if (navigator.webkitGetUserMedia) {
            // Chrome, Chromium, Webview, Opera.
            // Version matches Chrome/WebRTC version.
            result.browser = 'chrome';
            result.version = extractVersion(navigator.userAgent,
                /Chrom(e|ium)\/(\d+)\./, 2);
        } else if (navigator.mediaDevices &&
            navigator.userAgent.match(/Edge\/(\d+).(\d+)$/)) { // Edge.
            result.browser = 'edge';
            result.version = extractVersion(navigator.userAgent,
                /Edge\/(\d+).(\d+)$/, 2);
        } else if (window.RTCPeerConnection &&
            navigator.userAgent.match(/AppleWebKit\/(\d+)\./)) { // Safari.
            result.browser = 'safari';
            result.version = extractVersion(navigator.userAgent,
                /AppleWebKit\/(\d+)\./, 1);
        } else { // Default fallthrough: not supported.
            result.browser = 'Not a supported browser.';
            return result;
        }

return result;
    }
};

},{}]},{},[3])(3)
});