Use local pages for webrtc telemetry tests.

tools/perf/page_sets/webrtc_cases/adapter.js

+/*
+ * Copyright 2017 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.adapter = f()}})(function(){var define,module,exports;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){
+ /* 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 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: parts[1],
+    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;
+      default: // Unknown extensions are silently ignored.
+        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);
+
+  var type = candidate.type;
+  sdp.push('typ');
+  sdp.push(type);
+  if (type !== 'host' && candidate.relatedAddress &&
+      candidate.relatedPort) {
+    sdp.push('raddr');
+    sdp.push(candidate.relatedAddress); // was: relAddr
+    sdp.push('rport');
+    sdp.push(candidate.relatedPort); // was: relPort
+  }
+  if (candidate.tcpType && candidate.protocol.toLowerCase() === 'tcp') {
+    sdp.push('tcptype');
+    sdp.push(candidate.tcpType);
+  }
+  return 'candidate:' + sdp.join(' ');
+};
+
+// 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
+SDPUtils.parseExtmap = function(line) {
+  var parts = line.substr(9).split(' ');
+  return {
+    id: parseInt(parts[0], 10),
+    uri: parts[1]
+  };
+};
+
+// Generates a=extmap line from RTCRtpHeaderExtensionParameters or
+// RTCRtpHeaderExtension.
+SDPUtils.writeExtmap = function(headerExtension) {
+  return 'a=extmap:' + (headerExtension.id || headerExtension.preferredId) +
+       ' ' + 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 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.splitLines(mediaSection);
+  // Search in session part, too.
+  lines = lines.concat(SDPUtils.splitLines(sessionpart));
+  var fpLine = lines.filter(function(line) {
+    return line.indexOf('a=fingerprint:') === 0;
+  })[0].substr(14);
+  // Note: a=setup line is ignored since we use the 'auto' role.
+  var dtlsParameters = {
+    role: 'auto',
+    fingerprints: [{
+      algorithm: fpLine.split(' ')[0],
+      value: fpLine.split(' ')[1]
+    }]
+  };
+  return dtlsParameters;
+};
+
+// 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;
+
+  var flows = SDPUtils.matchPrefix(mediaSection, 'a=ssrc-group:FID')
+  .map(function(line) {
+    var parts = line.split(' ');
+    parts.shift();
+    return parts.map(function(part) {
+      return parseInt(part, 10);
+    });
+  });
+  if (flows.length > 0 && flows[0].length > 1 && flows[0][0] === primarySsrc) {
+    secondarySsrc = flows[0][1];
+  }
+
+  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) {
+      bandwidth = parseInt(bandwidth[0].substr(5), 10);
+    }
+    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 attrіbute.
+  // 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 an 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]};
+  }
+};
+
+SDPUtils.writeSessionBoilerplate = function() {
+  // FIXME: sess-id should be an NTP timestamp.
+  return 'v=0\r\n' +
+      'o=thisisadapterortc 8169639915646943137 2 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.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';
+};
+
+// Expose public methods.
+module.exports = SDPUtils;
+
+},{}],2:[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';
+
+// Shimming starts here.
+(function() {
+  // Utils.
+  var utils = require('./utils');
+  var logging = utils.log;
+  var browserDetails = utils.browserDetails;
+  // Export to the adapter global object visible in the browser.
+  module.exports.browserDetails = browserDetails;
+  module.exports.extractVersion = utils.extractVersion;
+  module.exports.disableLog = utils.disableLog;
+
+  // 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;
+
+  // Shim browser if found.
+  switch (browserDetails.browser) {
+    case 'chrome':
+      if (!chromeShim || !chromeShim.shimPeerConnection) {
+        logging('Chrome shim is not included in this adapter release.');
+        return;
+      }
+      logging('adapter.js shimming chrome.');
+      // Export to the adapter global object visible in the browser.
+      module.exports.browserShim = chromeShim;
+
+      chromeShim.shimGetUserMedia();
+      chromeShim.shimMediaStream();
+      utils.shimCreateObjectURL();
+      chromeShim.shimSourceObject();
+      chromeShim.shimPeerConnection();
+      chromeShim.shimOnTrack();
+      chromeShim.shimGetSendersWithDtmf();
+      break;
+    case 'firefox':
+      if (!firefoxShim || !firefoxShim.shimPeerConnection) {
+        logging('Firefox shim is not included in this adapter release.');
+        return;
+      }
+      logging('adapter.js shimming firefox.');
+      // Export to the adapter global object visible in the browser.
+      module.exports.browserShim = firefoxShim;
+
+      firefoxShim.shimGetUserMedia();
+      utils.shimCreateObjectURL();
+      firefoxShim.shimSourceObject();
+      firefoxShim.shimPeerConnection();
+      firefoxShim.shimOnTrack();
+      break;
+    case 'edge':
+      if (!edgeShim || !edgeShim.shimPeerConnection) {
+        logging('MS edge shim is not included in this adapter release.');
+        return;
+      }
+      logging('adapter.js shimming edge.');
+      // Export to the adapter global object visible in the browser.
+      module.exports.browserShim = edgeShim;
+
+      edgeShim.shimGetUserMedia();
+      utils.shimCreateObjectURL();
+      edgeShim.shimPeerConnection();
+      break;
+    case 'safari':
+      if (!safariShim) {
+        logging('Safari shim is not included in this adapter release.');
+        return;
+      }
+      logging('adapter.js shimming safari.');
+      // Export to the adapter global object visible in the browser.
+      module.exports.browserShim = safariShim;
+
+      safariShim.shimGetUserMedia();
+      break;
+    default:
+      logging('Unsupported browser!');
+  }
+})();
+
+},{"./chrome/chrome_shim":3,"./edge/edge_shim":5,"./firefox/firefox_shim":7,"./safari/safari_shim":9,"./utils":10}],3:[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 logging = require('../utils.js').log;
+var browserDetails = require('../utils.js').browserDetails;
+
+var chromeShim = {
+  shimMediaStream: function() {
+    window.MediaStream = window.MediaStream || window.webkitMediaStream;
+  },
+
+  shimOnTrack: function() {
+    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) {
+          var self = this;
+          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) {
+            // 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 event = new Event('track');
+              event.track = te.track;
+              event.receiver = {track: te.track};
+              event.streams = [e.stream];
+              self.dispatchEvent(event);
+            });
+            e.stream.getTracks().forEach(function(track) {
+              var event = new Event('track');
+              event.track = track;
+              event.receiver = {track: track};
+              event.streams = [e.stream];
+              this.dispatchEvent(event);
+            }.bind(this));
+          }.bind(this));
+        }
+      });
+    }
+  },
+
+  shimGetSendersWithDtmf: function() {
+    if (typeof window === 'object' && window.RTCPeerConnection &&
+        !('getSenders' in RTCPeerConnection.prototype) &&
+        'createDTMFSender' in RTCPeerConnection.prototype) {
+      RTCPeerConnection.prototype.getSenders = function() {
+        return this._senders;
+      };
+      var origAddStream = RTCPeerConnection.prototype.addStream;
+      var origRemoveStream = RTCPeerConnection.prototype.removeStream;
+
+      RTCPeerConnection.prototype.addStream = function(stream) {
+        var pc = this;
+        pc._senders = pc._senders || [];
+        origAddStream.apply(pc, [stream]);
+        stream.getTracks().forEach(function(track) {
+          pc._senders.push({
+            track: track,
+            get dtmf() {
+              if (this._dtmf === undefined) {
+                if (track.kind === 'audio') {
+                  this._dtmf = pc.createDTMFSender(track);
+                } else {
+                  this._dtmf = null;
+                }
+              }
+              return this._dtmf;
+            }
+          });
+        });
+      };
+
+      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
+          }
+        });
+      };
+    }
+  },
+
+  shimSourceObject: function() {
+    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);
+            });
+          }
+        });
+      }
+    }
+  },
+
+  shimPeerConnection: function() {
+    // The RTCPeerConnection object.
+    if (!window.RTCPeerConnection) {
+      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 webkitRTCPeerConnection(pcConfig, pcConstraints);
+      };
+      window.RTCPeerConnection.prototype = webkitRTCPeerConnection.prototype;
+      // wrap static methods. Currently just generateCertificate.
+      if (webkitRTCPeerConnection.generateCertificate) {
+        Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
+          get: function() {
+            return webkitRTCPeerConnection.generateCertificate;
+          }
+        });
+      }
+    }
+
+    var origGetStats = RTCPeerConnection.prototype.getStats;
+    RTCPeerConnection.prototype.getStats = function(selector,
+        successCallback, errorCallback) {
+      var self = 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, []);
+      }
+
+      var fixChromeStats_ = function(response) {
+        var standardReport = {};
+        var reports = response.result();
+        reports.forEach(function(report) {
+          var standardStats = {
+            id: report.id,
+            timestamp: report.timestamp,
+            type: {
+              localcandidate: 'local-candidate',
+              remotecandidate: 'remote-candidate'
+            }[report.type] || report.type
+          };
+          report.names().forEach(function(name) {
+            standardStats[name] = report.stat(name);
+          });
+          standardReport[standardStats.id] = standardStats;
+        });
+
+        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(self, [
+          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 = RTCPeerConnection.prototype[method];
+            RTCPeerConnection.prototype[method] = function() {
+              var args = arguments;
+              var self = this;
+              var promise = new Promise(function(resolve, reject) {
+                nativeMethod.apply(self, [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 = RTCPeerConnection.prototype[method];
+        RTCPeerConnection.prototype[method] = function() {
+          var self = 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(self, [resolve, reject, opts]);
+            });
+          }
+          return nativeMethod.apply(this, arguments);
+        };
+      });
+    }
+
+    // shim implicit creation of RTCSessionDescription/RTCIceCandidate
+    ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
+        .forEach(function(method) {
+          var nativeMethod = RTCPeerConnection.prototype[method];
+          RTCPeerConnection.prototype[method] = function() {
+            arguments[0] = new ((method === 'addIceCandidate') ?
+                RTCIceCandidate : RTCSessionDescription)(arguments[0]);
+            return nativeMethod.apply(this, arguments);
+          };
+        });
+
+    // support for addIceCandidate(null or undefined)
+    var nativeAddIceCandidate =
+        RTCPeerConnection.prototype.addIceCandidate;
+    RTCPeerConnection.prototype.addIceCandidate = function() {
+      if (!arguments[0]) {
+        if (arguments[1]) {
+          arguments[1].apply(null);
+        }
+        return Promise.resolve();
+      }
+      return nativeAddIceCandidate.apply(this, arguments);
+    };
+  }
+};
+
+
+// Expose public methods.
+module.exports = {
+  shimMediaStream: chromeShim.shimMediaStream,
+  shimOnTrack: chromeShim.shimOnTrack,
+  shimGetSendersWithDtmf: chromeShim.shimGetSendersWithDtmf,
+  shimSourceObject: chromeShim.shimSourceObject,
+  shimPeerConnection: chromeShim.shimPeerConnection,
+  shimGetUserMedia: require('./getusermedia')
+};
+
+},{"../utils.js":10,"./getusermedia":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 logging = require('../utils.js').log;
+var browserDetails = require('../utils.js').browserDetails;
+
+// Expose public methods.
+module.exports = function() {
+  var constraintsToChrome_ = function(c) {
+    if (typeof c !== 'object' || c.mandatory || c.optional) {
+      return c;
+    }
+    var cc = {};
+    Object.keys(c).forEach(function(key) {
+      if (key === 'require' || key === 'advanced' || key === 'mediaSource') {
+        return;
+      }
+      var r = (typeof c[key] === 'object') ? c[key] : {ideal: c[key]};
+      if (r.exact !== undefined && typeof r.exact === 'number') {
+        r.min = r.max = r.exact;
+      }
+      var oldname_ = function(prefix, name) {
+        if (prefix) {
+          return prefix + name.charAt(0).toUpperCase() + name.slice(1);
+        }
+        return (name === 'deviceId') ? 'sourceId' : name;
+      };
+      if (r.ideal !== undefined) {
+        cc.optional = cc.optional || [];
+        var oc = {};
+        if (typeof r.ideal === 'number') {
+          oc[oldname_('min', key)] = r.ideal;
+          cc.optional.push(oc);
+          oc = {};
+          oc[oldname_('max', key)] = r.ideal;
+          cc.optional.push(oc);
+        } else {
+          oc[oldname_('', key)] = r.ideal;
+          cc.optional.push(oc);
+        }
+      }
+      if (r.exact !== undefined && typeof r.exact !== 'number') {
+        cc.mandatory = cc.mandatory || {};
+        cc.mandatory[oldname_('', key)] = r.exact;
+      } else {
+        ['min', 'max'].forEach(function(mix) {
+          if (r[mix] !== undefined) {
+            cc.mandatory = cc.mandatory || {};
+            cc.mandatory[oldname_(mix, key)] = r[mix];
+          }
+        });
+      }
+    });
+    if (c.advanced) {
+      cc.optional = (cc.optional || []).concat(c.advanced);
+    }
+    return cc;
+  };
+
+  var shimConstraints_ = function(constraints, func) {
+    constraints = JSON.parse(JSON.stringify(constraints));
+    if (constraints && constraints.audio) {
+      constraints.audio = constraintsToChrome_(constraints.audio);
+    }
+    if (constraints && typeof constraints.video === 'object') {
+      // Shim facingMode for mobile, where it defaults to "user".
+      var face = constraints.video.facingMode;
+      face = face && ((typeof face === 'object') ? face : {ideal: face});
+      var getSupportedFacingModeLies = browserDetails.version < 59;
+
+      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;
+        if (face.exact === 'environment' || face.ideal === 'environment') {
+          // Look for "back" in label, or use last cam (typically back cam).
+          return navigator.mediaDevices.enumerateDevices()
+          .then(function(devices) {
+            devices = devices.filter(function(d) {
+              return d.kind === 'videoinput';
+            });
+            var back = devices.find(function(d) {
+              return d.label.toLowerCase().indexOf('back') !== -1;
+            }) || (devices.length && devices[devices.length - 1]);
+            if (back) {
+              constraints.video.deviceId = face.exact ? {exact: back.deviceId} :
+                                                        {ideal: back.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);
+  };
+
+  var shimError_ = function(e) {
+    return {
+      name: {
+        PermissionDeniedError: 'NotAllowedError',
+        ConstraintNotSatisfiedError: 'OverconstrainedError'
+      }[e.name] || e.name,
+      message: e.message,
+      constraint: e.constraintName,
+      toString: function() {
+        return this.name + (this.message && ': ') + this.message;
+      }
+    };
+  };
+
+  var getUserMedia_ = function(constraints, onSuccess, onError) {
+    shimConstraints_(constraints, function(c) {
+      navigator.webkitGetUserMedia(c, onSuccess, function(e) {
+        onError(shimError_(e));
+      });
+    });
+  };
+
+  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 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":10}],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 SDPUtils = require('sdp');
+var browserDetails = require('../utils').browserDetails;
+
+// sort tracks such that they follow an a-v-a-v...
+// pattern.
+function sortTracks(tracks) {
+  var audioTracks = tracks.filter(function(track) {
+    return track.kind === 'audio';
+  });
+  var videoTracks = tracks.filter(function(track) {
+    return track.kind === 'video';
+  });
+  tracks = [];
+  while (audioTracks.length || videoTracks.length) {
+    if (audioTracks.length) {
+      tracks.push(audioTracks.shift());
+    }
+    if (videoTracks.length) {
+      tracks.push(videoTracks.shift());
+    }
+  }
+  return tracks;
+}
+
+// Edge does not like
+// 1) stun:
+// 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) {
+  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;
+      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 &&
+            browserDetails.version >= 14393;
+      });
+
+      delete server.url;
+      server.urls = isString ? urls[0] : urls;
+      return !!urls.length;
+    }
+    return false;
+  });
+}
+
+var edgeShim = {
+  shimPeerConnection: function() {
+    if (window.RTCIceGatherer) {
+      // ORTC defines an RTCIceCandidate object but no constructor.
+      // Not implemented in Edge.
+      if (!window.RTCIceCandidate) {
+        window.RTCIceCandidate = function(args) {
+          return args;
+        };
+      }
+      // ORTC does not have a session description object but
+      // other browsers (i.e. Chrome) that will support both PC and ORTC
+      // in the future might have this defined already.
+      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(
+            MediaStreamTrack.prototype, 'enabled');
+        Object.defineProperty(MediaStreamTrack.prototype, 'enabled', {
+          set: function(value) {
+            origMSTEnabled.set.call(this, value);
+            var ev = new Event('enabled');
+            ev.enabled = value;
+            this.dispatchEvent(ev);
+          }
+        });
+      }
+    }
+
+    window.RTCPeerConnection = function(config) {
+      var self = this;
+
+      var _eventTarget = document.createDocumentFragment();
+      ['addEventListener', 'removeEventListener', 'dispatchEvent']
+          .forEach(function(method) {
+            self[method] = _eventTarget[method].bind(_eventTarget);
+          });
+
+      this.onicecandidate = null;
+      this.onaddstream = null;
+      this.ontrack = null;
+      this.onremovestream = null;
+      this.onsignalingstatechange = null;
+      this.oniceconnectionstatechange = null;
+      this.onicegatheringstatechange = null;
+      this.onnegotiationneeded = null;
+      this.ondatachannel = null;
+
+      this.localStreams = [];
+      this.remoteStreams = [];
+      this.getLocalStreams = function() {
+        return self.localStreams;
+      };
+      this.getRemoteStreams = function() {
+        return self.remoteStreams;
+      };
+
+      this.localDescription = new RTCSessionDescription({
+        type: '',
+        sdp: ''
+      });
+      this.remoteDescription = new RTCSessionDescription({
+        type: '',
+        sdp: ''
+      });
+      this.signalingState = 'stable';
+      this.iceConnectionState = 'new';
+      this.iceGatheringState = 'new';
+
+      this.iceOptions = {
+        gatherPolicy: 'all',
+        iceServers: []
+      };
+      if (config && config.iceTransportPolicy) {
+        switch (config.iceTransportPolicy) {
+          case 'all':
+          case 'relay':
+            this.iceOptions.gatherPolicy = config.iceTransportPolicy;
+            break;
+          default:
+            // don't set iceTransportPolicy.
+            break;
+        }
+      }
+      this.usingBundle = config && config.bundlePolicy === 'max-bundle';
+
+      if (config && config.iceServers) {
+        this.iceOptions.iceServers = filterIceServers(config.iceServers);
+      }
+      this._config = config;
+
+      // per-track iceGathers, iceTransports, dtlsTransports, rtpSenders, ...
+      // everything that is needed to describe a SDP m-line.
+      this.transceivers = [];
+
+      // since the iceGatherer is currently created in createOffer but we
+      // must not emit candidates until after setLocalDescription we buffer
+      // them in this array.
+      this._localIceCandidatesBuffer = [];
+    };
+
+    window.RTCPeerConnection.prototype._emitGatheringStateChange = function() {
+      var event = new Event('icegatheringstatechange');
+      this.dispatchEvent(event);
+      if (this.onicegatheringstatechange !== null) {
+        this.onicegatheringstatechange(event);
+      }
+    };
+
+    window.RTCPeerConnection.prototype._emitBufferedCandidates = function() {
+      var self = this;
+      var sections = SDPUtils.splitSections(self.localDescription.sdp);
+      // FIXME: need to apply ice candidates in a way which is async but
+      // in-order
+      this._localIceCandidatesBuffer.forEach(function(event) {
+        var end = !event.candidate || Object.keys(event.candidate).length === 0;
+        if (end) {
+          for (var j = 1; j < sections.length; j++) {
+            if (sections[j].indexOf('\r\na=end-of-candidates\r\n') === -1) {
+              sections[j] += 'a=end-of-candidates\r\n';
+            }
+          }
+        } else {
+          sections[event.candidate.sdpMLineIndex + 1] +=
+              'a=' + event.candidate.candidate + '\r\n';
+        }
+        self.localDescription.sdp = sections.join('');
+        self.dispatchEvent(event);
+        if (self.onicecandidate !== null) {
+          self.onicecandidate(event);
+        }
+        if (!event.candidate && self.iceGatheringState !== 'complete') {
+          var complete = self.transceivers.every(function(transceiver) {
+            return transceiver.iceGatherer &&
+                transceiver.iceGatherer.state === 'completed';
+          });
+          if (complete && self.iceGatheringStateChange !== 'complete') {
+            self.iceGatheringState = 'complete';
+            self._emitGatheringStateChange();
+          }
+        }
+      });
+      this._localIceCandidatesBuffer = [];
+    };
+
+    window.RTCPeerConnection.prototype.getConfiguration = function() {
+      return this._config;
+    };
+
+    window.RTCPeerConnection.prototype.addStream = function(stream) {
+      if (browserDetails.version >= 15025) {
+        this.localStreams.push(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;
+          });
+        });
+        this.localStreams.push(clonedStream);
+      }
+      this._maybeFireNegotiationNeeded();
+    };
+
+    window.RTCPeerConnection.prototype.removeStream = function(stream) {
+      var idx = this.localStreams.indexOf(stream);
+      if (idx > -1) {
+        this.localStreams.splice(idx, 1);
+        this._maybeFireNegotiationNeeded();
+      }
+    };
+
+    window.RTCPeerConnection.prototype.getSenders = function() {
+      return this.transceivers.filter(function(transceiver) {
+        return !!transceiver.rtpSender;
+      })
+      .map(function(transceiver) {
+        return transceiver.rtpSender;
+      });
+    };
+
+    window.RTCPeerConnection.prototype.getReceivers = function() {
+      return this.transceivers.filter(function(transceiver) {
+        return !!transceiver.rtpReceiver;
+      })
+      .map(function(transceiver) {
+        return transceiver.rtpReceiver;
+      });
+    };
+
+    // Determines the intersection of local and remote capabilities.
+    window.RTCPeerConnection.prototype._getCommonCapabilities =
+        function(localCapabilities, remoteCapabilities) {
+          var commonCapabilities = {
+            codecs: [],
+            headerExtensions: [],
+            fecMechanisms: []
+          };
+
+          var findCodecByPayloadType = function(pt, codecs) {
+            pt = parseInt(pt, 10);
+            for (var i = 0; i < codecs.length; i++) {
+              if (codecs[i].payloadType === pt ||
+                  codecs[i].preferredPayloadType === pt) {
+                return codecs[i];
+              }
+            }
+          };
+
+          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;
+        };
+
+    // Create ICE gatherer, ICE transport and DTLS transport.
+    window.RTCPeerConnection.prototype._createIceAndDtlsTransports =
+        function(mid, sdpMLineIndex) {
+          var self = this;
+          var iceGatherer = new RTCIceGatherer(self.iceOptions);
+          var iceTransport = new RTCIceTransport(iceGatherer);
+          iceGatherer.onlocalcandidate = function(evt) {
+            var event = new Event('icecandidate');
+            event.candidate = {sdpMid: mid, sdpMLineIndex: sdpMLineIndex};
+
+            var cand = evt.candidate;
+            var end = !cand || Object.keys(cand).length === 0;
+            // Edge emits an empty object for RTCIceCandidateComplete‥
+            if (end) {
+              // polyfill since RTCIceGatherer.state is not implemented in
+              // Edge 10547 yet.
+              if (iceGatherer.state === undefined) {
+                iceGatherer.state = 'completed';
+              }
+            } else {
+              // RTCIceCandidate doesn't have a component, needs to be added
+              cand.component = iceTransport.component === 'RTCP' ? 2 : 1;
+              event.candidate.candidate = SDPUtils.writeCandidate(cand);
+            }
+
+            // update local description.
+            var sections = SDPUtils.splitSections(self.localDescription.sdp);
+            if (!end) {
+              sections[event.candidate.sdpMLineIndex + 1] +=
+                  'a=' + event.candidate.candidate + '\r\n';
+            } else {
+              sections[event.candidate.sdpMLineIndex + 1] +=
+                  'a=end-of-candidates\r\n';
+            }
+            self.localDescription.sdp = sections.join('');
+            var transceivers = self._pendingOffer ? self._pendingOffer :
+                self.transceivers;
+            var complete = transceivers.every(function(transceiver) {
+              return transceiver.iceGatherer &&
+                  transceiver.iceGatherer.state === 'completed';
+            });
+
+            // Emit candidate if localDescription is set.
+            // Also emits null candidate when all gatherers are complete.
+            switch (self.iceGatheringState) {
+              case 'new':
+                if (!end) {
+                  self._localIceCandidatesBuffer.push(event);
+                }
+                if (end && complete) {
+                  self._localIceCandidatesBuffer.push(
+                      new Event('icecandidate'));
+                }
+                break;
+              case 'gathering':
+                self._emitBufferedCandidates();
+                if (!end) {
+                  self.dispatchEvent(event);
+                  if (self.onicecandidate !== null) {
+                    self.onicecandidate(event);
+                  }
+                }
+                if (complete) {
+                  self.dispatchEvent(new Event('icecandidate'));
+                  if (self.onicecandidate !== null) {
+                    self.onicecandidate(new Event('icecandidate'));
+                  }
+                  self.iceGatheringState = 'complete';
+                  self._emitGatheringStateChange();
+                }
+                break;
+              case 'complete':
+                // should not happen... currently!
+                break;
+              default: // no-op.
+                break;
+            }
+          };
+          iceTransport.onicestatechange = function() {
+            self._updateConnectionState();
+          };
+
+          var dtlsTransport = new RTCDtlsTransport(iceTransport);
+          dtlsTransport.ondtlsstatechange = function() {
+            self._updateConnectionState();
+          };
+          dtlsTransport.onerror = function() {
+            // onerror does not set state to failed by itself.
+            dtlsTransport.state = 'failed';
+            self._updateConnectionState();
+          };
+
+          return {
+            iceGatherer: iceGatherer,
+            iceTransport: iceTransport,
+            dtlsTransport: dtlsTransport
+          };
+        };
+
+    // Start the RTP Sender and Receiver for a transceiver.
+    window.RTCPeerConnection.prototype._transceive = function(transceiver,
+        send, recv) {
+      var params = this._getCommonCapabilities(transceiver.localCapabilities,
+          transceiver.remoteCapabilities);
+      if (send && transceiver.rtpSender) {
+        params.encodings = transceiver.sendEncodingParameters;
+        params.rtcp = {
+          cname: SDPUtils.localCName
+        };
+        if (transceiver.recvEncodingParameters.length) {
+          params.rtcp.ssrc = transceiver.recvEncodingParameters[0].ssrc;
+        }
+        transceiver.rtpSender.send(params);
+      }
+      if (recv && transceiver.rtpReceiver) {
+        // remove RTX field in Edge 14942
+        if (transceiver.kind === 'video'
+            && transceiver.recvEncodingParameters
+            && browserDetails.version < 15019) {
+          transceiver.recvEncodingParameters.forEach(function(p) {
+            delete p.rtx;
+          });
+        }
+        params.encodings = transceiver.recvEncodingParameters;
+        params.rtcp = {
+          cname: transceiver.cname
+        };
+        if (transceiver.sendEncodingParameters.length) {
+          params.rtcp.ssrc = transceiver.sendEncodingParameters[0].ssrc;
+        }
+        transceiver.rtpReceiver.receive(params);
+      }
+    };
+
+    window.RTCPeerConnection.prototype.setLocalDescription =
+        function(description) {
+          var self = this;
+          var sections;
+          var sessionpart;
+          if (description.type === 'offer') {
+            // FIXME: What was the purpose of this empty if statement?
+            // if (!this._pendingOffer) {
+            // } else {
+            if (this._pendingOffer) {
+              // 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);
+                self._pendingOffer[sdpMLineIndex].localCapabilities = caps;
+              });
+              this.transceivers = this._pendingOffer;
+              delete this._pendingOffer;
+            }
+          } else if (description.type === 'answer') {
+            sections = SDPUtils.splitSections(self.remoteDescription.sdp);
+            sessionpart = sections.shift();
+            var isIceLite = SDPUtils.matchPrefix(sessionpart,
+                'a=ice-lite').length > 0;
+            sections.forEach(function(mediaSection, sdpMLineIndex) {
+              var transceiver = self.transceivers[sdpMLineIndex];
+              var iceGatherer = transceiver.iceGatherer;
+              var iceTransport = transceiver.iceTransport;
+              var dtlsTransport = transceiver.dtlsTransport;
+              var localCapabilities = transceiver.localCapabilities;
+              var remoteCapabilities = transceiver.remoteCapabilities;
+
+              var rejected = mediaSection.split('\n', 1)[0]
+                  .split(' ', 2)[1] === '0';
+
+              if (!rejected && !transceiver.isDatachannel) {
+                var remoteIceParameters = SDPUtils.getIceParameters(
+                    mediaSection, sessionpart);
+                var remoteDtlsParameters = SDPUtils.getDtlsParameters(
+                    mediaSection, sessionpart);
+                if (isIceLite) {
+                  remoteDtlsParameters.role = 'server';
+                }
+
+                if (!self.usingBundle || sdpMLineIndex === 0) {
+                  iceTransport.start(iceGatherer, remoteIceParameters,
+                      isIceLite ? 'controlling' : 'controlled');
+                  dtlsTransport.start(remoteDtlsParameters);
+                }
+
+                // Calculate intersection of capabilities.
+                var params = self._getCommonCapabilities(localCapabilities,
+                    remoteCapabilities);
+
+                // Start the RTCRtpSender. The RTCRtpReceiver for this
+                // transceiver has already been started in setRemoteDescription.
+                self._transceive(transceiver,
+                    params.codecs.length > 0,
+                    false);
+              }
+            });
+          }
+
+          this.localDescription = {
+            type: description.type,
+            sdp: description.sdp
+          };
+          switch (description.type) {
+            case 'offer':
+              this._updateSignalingState('have-local-offer');
+              break;
+            case 'answer':
+              this._updateSignalingState('stable');
+              break;
+            default:
+              throw new TypeError('unsupported type "' + description.type +
+                  '"');
+          }
+
+          // If a success callback was provided, emit ICE candidates after it
+          // has been executed. Otherwise, emit callback after the Promise is
+          // resolved.
+          var hasCallback = arguments.length > 1 &&
+            typeof arguments[1] === 'function';
+          if (hasCallback) {
+            var cb = arguments[1];
+            window.setTimeout(function() {
+              cb();
+              if (self.iceGatheringState === 'new') {
+                self.iceGatheringState = 'gathering';
+                self._emitGatheringStateChange();
+              }
+              self._emitBufferedCandidates();
+            }, 0);
+          }
+          var p = Promise.resolve();
+          p.then(function() {
+            if (!hasCallback) {
+              if (self.iceGatheringState === 'new') {
+                self.iceGatheringState = 'gathering';
+                self._emitGatheringStateChange();
+              }
+              // Usually candidates will be emitted earlier.
+              window.setTimeout(self._emitBufferedCandidates.bind(self), 500);
+            }
+          });
+          return p;
+        };
+
+    window.RTCPeerConnection.prototype.setRemoteDescription =
+        function(description) {
+          var self = this;
+          var stream = new MediaStream();
+          var receiverList = [];
+          var sections = SDPUtils.splitSections(description.sdp);
+          var sessionpart = sections.shift();
+          var isIceLite = SDPUtils.matchPrefix(sessionpart,
+              'a=ice-lite').length > 0;
+          this.usingBundle = SDPUtils.matchPrefix(sessionpart,
+              'a=group:BUNDLE ').length > 0;
+          sections.forEach(function(mediaSection, sdpMLineIndex) {
+            var lines = SDPUtils.splitLines(mediaSection);
+            var mline = lines[0].substr(2).split(' ');
+            var kind = mline[0];
+            var rejected = mline[1] === '0';
+            var direction = SDPUtils.getDirection(mediaSection, sessionpart);
+
+            var mid = SDPUtils.matchPrefix(mediaSection, 'a=mid:');
+            if (mid.length) {
+              mid = mid[0].substr(6);
+            } else {
+              mid = SDPUtils.generateIdentifier();
+            }
+
+            // Reject datachannels which are not implemented yet.
+            if (kind === 'application' && mline[2] === 'DTLS/SCTP') {
+              self.transceivers[sdpMLineIndex] = {
+                mid: mid,
+                isDatachannel: true
+              };
+              return;
+            }
+
+            var transceiver;
+            var iceGatherer;
+            var iceTransport;
+            var dtlsTransport;
+            var rtpSender;
+            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 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) {
+              cname = remoteSsrc.value;
+            }
+
+            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';
+                });
+            if (description.type === 'offer' && !rejected) {
+              var transports = self.usingBundle && sdpMLineIndex > 0 ? {
+                iceGatherer: self.transceivers[0].iceGatherer,
+                iceTransport: self.transceivers[0].iceTransport,
+                dtlsTransport: self.transceivers[0].dtlsTransport
+              } : self._createIceAndDtlsTransports(mid, sdpMLineIndex);
+
+              if (isComplete && (!self.usingBundle || sdpMLineIndex === 0)) {
+                transports.iceTransport.setRemoteCandidates(cands);
+              }
+
+              localCapabilities = RTCRtpReceiver.getCapabilities(kind);
+
+              // filter RTX until additional stuff needed for RTX is implemented
+              // in adapter.js
+              if (browserDetails.version < 15019) {
+                localCapabilities.codecs = localCapabilities.codecs.filter(
+                    function(codec) {
+                      return codec.name !== 'rtx';
+                    });
+              }
+
+              sendEncodingParameters = [{
+                ssrc: (2 * sdpMLineIndex + 2) * 1001
+              }];
+
+              if (direction === 'sendrecv' || direction === 'sendonly') {
+                rtpReceiver = new RTCRtpReceiver(transports.dtlsTransport,
+                    kind);
+
+                track = rtpReceiver.track;
+                receiverList.push([track, rtpReceiver]);
+                // FIXME: not correct when there are multiple streams but that
+                // is not currently supported in this shim.
+                stream.addTrack(track);
+              }
+
+              // FIXME: look at direction.
+              if (self.localStreams.length > 0 &&
+                  self.localStreams[0].getTracks().length >= sdpMLineIndex) {
+                var localTrack;
+                if (kind === 'audio') {
+                  localTrack = self.localStreams[0].getAudioTracks()[0];
+                } else if (kind === 'video') {
+                  localTrack = self.localStreams[0].getVideoTracks()[0];
+                }
+                if (localTrack) {
+                  // add RTX
+                  if (browserDetails.version >= 15019 && kind === 'video') {
+                    sendEncodingParameters[0].rtx = {
+                      ssrc: (2 * sdpMLineIndex + 2) * 1001 + 1
+                    };
+                  }
+                  rtpSender = new RTCRtpSender(localTrack,
+                      transports.dtlsTransport);
+                }
+              }
+
+              self.transceivers[sdpMLineIndex] = {
+                iceGatherer: transports.iceGatherer,
+                iceTransport: transports.iceTransport,
+                dtlsTransport: transports.dtlsTransport,
+                localCapabilities: localCapabilities,
+                remoteCapabilities: remoteCapabilities,
+                rtpSender: rtpSender,
+                rtpReceiver: rtpReceiver,
+                kind: kind,
+                mid: mid,
+                cname: cname,
+                sendEncodingParameters: sendEncodingParameters,
+                recvEncodingParameters: recvEncodingParameters
+              };
+              // Start the RTCRtpReceiver now. The RTPSender is started in
+              // setLocalDescription.
+              self._transceive(self.transceivers[sdpMLineIndex],
+                  false,
+                  direction === 'sendrecv' || direction === 'sendonly');
+            } else if (description.type === 'answer' && !rejected) {
+              transceiver = self.transceivers[sdpMLineIndex];
+              iceGatherer = transceiver.iceGatherer;
+              iceTransport = transceiver.iceTransport;
+              dtlsTransport = transceiver.dtlsTransport;
+              rtpSender = transceiver.rtpSender;
+              rtpReceiver = transceiver.rtpReceiver;
+              sendEncodingParameters = transceiver.sendEncodingParameters;
+              localCapabilities = transceiver.localCapabilities;
+
+              self.transceivers[sdpMLineIndex].recvEncodingParameters =
+                  recvEncodingParameters;
+              self.transceivers[sdpMLineIndex].remoteCapabilities =
+                  remoteCapabilities;
+              self.transceivers[sdpMLineIndex].cname = cname;
+
+              if ((isIceLite || isComplete) && cands.length) {
+                iceTransport.setRemoteCandidates(cands);
+              }
+              if (!self.usingBundle || sdpMLineIndex === 0) {
+                iceTransport.start(iceGatherer, remoteIceParameters,
+                    'controlling');
+                dtlsTransport.start(remoteDtlsParameters);
+              }
+
+              self._transceive(transceiver,
+                  direction === 'sendrecv' || direction === 'recvonly',
+                  direction === 'sendrecv' || direction === 'sendonly');
+
+              if (rtpReceiver &&
+                  (direction === 'sendrecv' || direction === 'sendonly')) {
+                track = rtpReceiver.track;
+                receiverList.push([track, rtpReceiver]);
+                stream.addTrack(track);
+              } else {
+                // FIXME: actually the receiver should be created later.
+                delete transceiver.rtpReceiver;
+              }
+            }
+          });
+
+          this.remoteDescription = {
+            type: description.type,
+            sdp: description.sdp
+          };
+          switch (description.type) {
+            case 'offer':
+              this._updateSignalingState('have-remote-offer');
+              break;
+            case 'answer':
+              this._updateSignalingState('stable');
+              break;
+            default:
+              throw new TypeError('unsupported type "' + description.type +
+                  '"');
+          }
+          if (stream.getTracks().length) {
+            self.remoteStreams.push(stream);
+            window.setTimeout(function() {
+              var event = new Event('addstream');
+              event.stream = stream;
+              self.dispatchEvent(event);
+              if (self.onaddstream !== null) {
+                window.setTimeout(function() {
+                  self.onaddstream(event);
+                }, 0);
+              }
+
+              receiverList.forEach(function(item) {
+                var track = item[0];
+                var receiver = item[1];
+                var trackEvent = new Event('track');
+                trackEvent.track = track;
+                trackEvent.receiver = receiver;
+                trackEvent.streams = [stream];
+                self.dispatchEvent(trackEvent);
+                if (self.ontrack !== null) {
+                  window.setTimeout(function() {
+                    self.ontrack(trackEvent);
+                  }, 0);
+                }
+              });
+            }, 0);
+          }
+          if (arguments.length > 1 && typeof arguments[1] === 'function') {
+            window.setTimeout(arguments[1], 0);
+          }
+          return Promise.resolve();
+        };
+
+    window.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._updateSignalingState('closed');
+    };
+
+    // Update the signaling state.
+    window.RTCPeerConnection.prototype._updateSignalingState =
+        function(newState) {
+          this.signalingState = newState;
+          var event = new Event('signalingstatechange');
+          this.dispatchEvent(event);
+          if (this.onsignalingstatechange !== null) {
+            this.onsignalingstatechange(event);
+          }
+        };
+
+    // Determine whether to fire the negotiationneeded event.
+    window.RTCPeerConnection.prototype._maybeFireNegotiationNeeded =
+        function() {
+          // Fire away (for now).
+          var event = new Event('negotiationneeded');
+          this.dispatchEvent(event);
+          if (this.onnegotiationneeded !== null) {
+            this.onnegotiationneeded(event);
+          }
+        };
+
+    // Update the connection state.
+    window.RTCPeerConnection.prototype._updateConnectionState = function() {
+      var self = this;
+      var newState;
+      var states = {
+        'new': 0,
+        closed: 0,
+        connecting: 0,
+        checking: 0,
+        connected: 0,
+        completed: 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 || states.checking > 0) {
+        newState = 'connecting';
+      } else if (states.disconnected > 0) {
+        newState = 'disconnected';
+      } else if (states.new > 0) {
+        newState = 'new';
+      } else if (states.connected > 0 || states.completed > 0) {
+        newState = 'connected';
+      }
+
+      if (newState !== self.iceConnectionState) {
+        self.iceConnectionState = newState;
+        var event = new Event('iceconnectionstatechange');
+        this.dispatchEvent(event);
+        if (this.oniceconnectionstatechange !== null) {
+          this.oniceconnectionstatechange(event);
+        }
+      }
+    };
+
+    window.RTCPeerConnection.prototype.createOffer = function() {
+      var self = this;
+      if (this._pendingOffer) {
+        throw new Error('createOffer called while there is a pending offer.');
+      }
+      var offerOptions;
+      if (arguments.length === 1 && typeof arguments[0] !== 'function') {
+        offerOptions = arguments[0];
+      } else if (arguments.length === 3) {
+        offerOptions = arguments[2];
+      }
+
+      var tracks = [];
+      var numAudioTracks = 0;
+      var numVideoTracks = 0;
+      // Default to sendrecv.
+      if (this.localStreams.length) {
+        numAudioTracks = this.localStreams[0].getAudioTracks().length;
+        numVideoTracks = this.localStreams[0].getVideoTracks().length;
+      }
+      // Determine number of audio and video tracks we need to send/recv.
+      if (offerOptions) {
+        // Reject Chrome legacy constraints.
+        if (offerOptions.mandatory || offerOptions.optional) {
+          throw new TypeError(
+              'Legacy mandatory/optional constraints not supported.');
+        }
+        if (offerOptions.offerToReceiveAudio !== undefined) {
+          numAudioTracks = offerOptions.offerToReceiveAudio;
+        }
+        if (offerOptions.offerToReceiveVideo !== undefined) {
+          numVideoTracks = offerOptions.offerToReceiveVideo;
+        }
+      }
+      if (this.localStreams.length) {
+        // Push local streams.
+        this.localStreams[0].getTracks().forEach(function(track) {
+          tracks.push({
+            kind: track.kind,
+            track: track,
+            wantReceive: track.kind === 'audio' ?
+                numAudioTracks > 0 : numVideoTracks > 0
+          });
+          if (track.kind === 'audio') {
+            numAudioTracks--;
+          } else if (track.kind === 'video') {
+            numVideoTracks--;
+          }
+        });
+      }
+      // Create M-lines for recvonly streams.
+      while (numAudioTracks > 0 || numVideoTracks > 0) {
+        if (numAudioTracks > 0) {
+          tracks.push({
+            kind: 'audio',
+            wantReceive: true
+          });
+          numAudioTracks--;
+        }
+        if (numVideoTracks > 0) {
+          tracks.push({
+            kind: 'video',
+            wantReceive: true
+          });
+          numVideoTracks--;
+        }
+      }
+      // reorder tracks
+      tracks = sortTracks(tracks);
+
+      var sdp = SDPUtils.writeSessionBoilerplate();
+      var transceivers = [];
+      tracks.forEach(function(mline, sdpMLineIndex) {
+        // For each track, create an ice gatherer, ice transport,
+        // dtls transport, potentially rtpsender and rtpreceiver.
+        var track = mline.track;
+        var kind = mline.kind;
+        var mid = SDPUtils.generateIdentifier();
+
+        var transports = self.usingBundle && sdpMLineIndex > 0 ? {
+          iceGatherer: transceivers[0].iceGatherer,
+          iceTransport: transceivers[0].iceTransport,
+          dtlsTransport: transceivers[0].dtlsTransport
+        } : self._createIceAndDtlsTransports(mid, sdpMLineIndex);
+
+        var localCapabilities = RTCRtpSender.getCapabilities(kind);
+        // filter RTX until additional stuff needed for RTX is implemented
+        // in adapter.js
+        if (browserDetails.version < 15019) {
+          localCapabilities.codecs = localCapabilities.codecs.filter(
+              function(codec) {
+                return codec.name !== 'rtx';
+              });
+        }
+        localCapabilities.codecs.forEach(function(codec) {
+          // work around https://bugs.chromium.org/p/webrtc/issues/detail?id=6552
+          // by adding level-asymmetry-allowed=1
+          if (codec.name === 'H264' &&
+              codec.parameters['level-asymmetry-allowed'] === undefined) {
+            codec.parameters['level-asymmetry-allowed'] = '1';
+          }
+        });
+
+        var rtpSender;
+        var rtpReceiver;
+
+        // generate an ssrc now, to be used later in rtpSender.send
+        var sendEncodingParameters = [{
+          ssrc: (2 * sdpMLineIndex + 1) * 1001
+        }];
+        if (track) {
+          // add RTX
+          if (browserDetails.version >= 15019 && kind === 'video') {
+            sendEncodingParameters[0].rtx = {
+              ssrc: (2 * sdpMLineIndex + 1) * 1001 + 1
+            };
+          }
+          rtpSender = new RTCRtpSender(track, transports.dtlsTransport);
+        }
+
+        if (mline.wantReceive) {
+          rtpReceiver = new RTCRtpReceiver(transports.dtlsTransport, kind);
+        }
+
+        transceivers[sdpMLineIndex] = {
+          iceGatherer: transports.iceGatherer,
+          iceTransport: transports.iceTransport,
+          dtlsTransport: transports.dtlsTransport,
+          localCapabilities: localCapabilities,
+          remoteCapabilities: null,
+          rtpSender: rtpSender,
+          rtpReceiver: rtpReceiver,
+          kind: kind,
+          mid: mid,
+          sendEncodingParameters: sendEncodingParameters,
+          recvEncodingParameters: null
+        };
+      });
+      if (this.usingBundle) {
+        sdp += 'a=group:BUNDLE ' + transceivers.map(function(t) {
+          return t.mid;
+        }).join(' ') + '\r\n';
+      }
+      tracks.forEach(function(mline, sdpMLineIndex) {
+        var transceiver = transceivers[sdpMLineIndex];
+        sdp += SDPUtils.writeMediaSection(transceiver,
+            transceiver.localCapabilities, 'offer', self.localStreams[0]);
+      });
+
+      this._pendingOffer = transceivers;
+      var desc = new RTCSessionDescription({
+        type: 'offer',
+        sdp: sdp
+      });
+      if (arguments.length && typeof arguments[0] === 'function') {
+        window.setTimeout(arguments[0], 0, desc);
+      }
+      return Promise.resolve(desc);
+    };
+
+    window.RTCPeerConnection.prototype.createAnswer = function() {
+      var self = this;
+
+      var sdp = SDPUtils.writeSessionBoilerplate();
+      if (this.usingBundle) {
+        sdp += 'a=group:BUNDLE ' + this.transceivers.map(function(t) {
+          return t.mid;
+        }).join(' ') + '\r\n';
+      }
+      this.transceivers.forEach(function(transceiver) {
+        if (transceiver.isDatachannel) {
+          sdp += 'm=application 0 DTLS/SCTP 5000\r\n' +
+              'c=IN IP4 0.0.0.0\r\n' +
+              'a=mid:' + transceiver.mid + '\r\n';
+          return;
+        }
+        // Calculate intersection of capabilities.
+        var commonCapabilities = self._getCommonCapabilities(
+            transceiver.localCapabilities,
+            transceiver.remoteCapabilities);
+
+        sdp += SDPUtils.writeMediaSection(transceiver, commonCapabilities,
+            'answer', self.localStreams[0]);
+      });
+
+      var desc = new RTCSessionDescription({
+        type: 'answer',
+        sdp: sdp
+      });
+      if (arguments.length && typeof arguments[0] === 'function') {
+        window.setTimeout(arguments[0], 0, desc);
+      }
+      return Promise.resolve(desc);
+    };
+
+    window.RTCPeerConnection.prototype.addIceCandidate = function(candidate) {
+      if (!candidate) {
+        for (var j = 0; j < this.transceivers.length; j++) {
+          this.transceivers[j].iceTransport.addRemoteCandidate({});
+          if (this.usingBundle) {
+            return Promise.resolve();
+          }
+        }
+      } else {
+        var mLineIndex = candidate.sdpMLineIndex;
+        if (candidate.sdpMid) {
+          for (var i = 0; i < this.transceivers.length; i++) {
+            if (this.transceivers[i].mid === candidate.sdpMid) {
+              mLineIndex = i;
+              break;
+            }
+          }
+        }
+        var transceiver = this.transceivers[mLineIndex];
+        if (transceiver) {
+          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 Promise.resolve();
+          }
+          // Ignore RTCP candidates, we assume RTCP-MUX.
+          if (cand.component !== '1') {
+            return Promise.resolve();
+          }
+          transceiver.iceTransport.addRemoteCandidate(cand);
+
+          // update the remoteDescription.
+          var sections = SDPUtils.splitSections(this.remoteDescription.sdp);
+          sections[mLineIndex + 1] += (cand.type ? candidate.candidate.trim()
+              : 'a=end-of-candidates') + '\r\n';
+          this.remoteDescription.sdp = sections.join('');
+        }
+      }
+      if (arguments.length > 1 && typeof arguments[1] === 'function') {
+        window.setTimeout(arguments[1], 0);
+      }
+      return Promise.resolve();
+    };
+
+    window.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 cb = arguments.length > 1 && typeof arguments[1] === 'function' &&
+          arguments[1];
+      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]);
+            });
+          });
+          if (cb) {
+            window.setTimeout(cb, 0, results);
+          }
+          resolve(results);
+        });
+      });
+    };
+  }
+};
+
+// Expose public methods.
+module.exports = {
+  shimPeerConnection: edgeShim.shimPeerConnection,
+  shimGetUserMedia: require('./getusermedia')
+};
+
+},{"../utils":10,"./getusermedia":6,"sdp":1}],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';
+
+// Expose public methods.
+module.exports = function() {
+  var shimError_ = function(e) {
+    return {
+      name: {PermissionDeniedError: 'NotAllowedError'}[e.name] || e.name,
+      message: e.message,
+      constraint: e.constraint,
+      toString: function() {
+        return this.name;
+      }
+    };
+  };
+
+  // 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));
+    });
+  };
+};
+
+},{}],7:[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 browserDetails = require('../utils').browserDetails;
+
+var firefoxShim = {
+  shimOnTrack: function() {
+    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.streams = [e.stream];
+              this.dispatchEvent(event);
+            }.bind(this));
+          }.bind(this));
+        }
+      });
+    }
+  },
+
+  shimSourceObject: function() {
+    // 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() {
+    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 mozRTCPeerConnection(pcConfig, pcConstraints);
+      };
+      window.RTCPeerConnection.prototype = mozRTCPeerConnection.prototype;
+
+      // wrap static methods. Currently just generateCertificate.
+      if (mozRTCPeerConnection.generateCertificate) {
+        Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
+          get: function() {
+            return mozRTCPeerConnection.generateCertificate;
+          }
+        });
+      }
+
+      window.RTCSessionDescription = mozRTCSessionDescription;
+      window.RTCIceCandidate = mozRTCIceCandidate;
+    }
+
+    // shim away need for obsolete RTCIceCandidate/RTCSessionDescription.
+    ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
+        .forEach(function(method) {
+          var nativeMethod = RTCPeerConnection.prototype[method];
+          RTCPeerConnection.prototype[method] = function() {
+            arguments[0] = new ((method === 'addIceCandidate') ?
+                RTCIceCandidate : RTCSessionDescription)(arguments[0]);
+            return nativeMethod.apply(this, arguments);
+          };
+        });
+
+    // support for addIceCandidate(null or undefined)
+    var nativeAddIceCandidate =
+        RTCPeerConnection.prototype.addIceCandidate;
+    RTCPeerConnection.prototype.addIceCandidate = function() {
+      if (!arguments[0]) {
+        if (arguments[1]) {
+          arguments[1].apply(null);
+        }
+        return Promise.resolve();
+      }
+      return nativeAddIceCandidate.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'
+    };
+
+    var nativeGetStats = RTCPeerConnection.prototype.getStats;
+    RTCPeerConnection.prototype.getStats = function(selector, onSucc, onErr) {
+      return nativeGetStats.apply(this, [selector || null])
+        .then(function(stats) {
+          if (browserDetails.version < 48) {
+            stats = makeMapStats(stats);
+          }
+          if (browserDetails.version < 53 && !onSucc) {
+            // Shim only promise getStats with spec-hyphens in type names
+            // Leave callback version alone; misc old uses of forEach before Map
+            try {
+              stats.forEach(function(stat) {
+                stat.type = modernStatsTypes[stat.type] || stat.type;
+              });
+            } catch (e) {
+              if (e.name !== 'TypeError') {
+                throw e;
+              }
+              // Avoid TypeError: "type" is read-only, in old versions. 34-43ish
+              stats.forEach(function(stat, i) {
+                stats.set(i, Object.assign({}, stat, {
+                  type: modernStatsTypes[stat.type] || stat.type
+                }));
+              });
+            }
+          }
+          return stats;
+        })
+        .then(onSucc, onErr);
+    };
+  }
+};
+
+// Expose public methods.
+module.exports = {
+  shimOnTrack: firefoxShim.shimOnTrack,
+  shimSourceObject: firefoxShim.shimSourceObject,
+  shimPeerConnection: firefoxShim.shimPeerConnection,
+  shimGetUserMedia: require('./getusermedia')
+};
+
+},{"../utils":10,"./getusermedia":8}],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 logging = require('../utils').log;
+var browserDetails = require('../utils').browserDetails;
+
+// Expose public methods.
+module.exports = function() {
+  var shimError_ = function(e) {
+    return {
+      name: {
+        SecurityError: 'NotAllowedError',
+        PermissionDeniedError: 'NotAllowedError'
+      }[e.name] || e.name,
+      message: {
+        'The operation is insecure.': 'The request is not allowed by the ' +
+        'user agent or the platform in the current context.'
+      }[e.message] || e.message,
+      constraint: e.constraint,
+      toString: function() {
+        return this.name + (this.message && ': ') + this.message;
+      }
+    };
+  };
+
+  // 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));
+      });
+    };
+  }
+  navigator.getUserMedia = function(constraints, onSuccess, onError) {
+    if (browserDetails.version < 44) {
+      return getUserMedia_(constraints, onSuccess, onError);
+    }
+    // Replace Firefox 44+'s deprecation warning with unprefixed version.
+    console.warn('navigator.getUserMedia has been replaced by ' +
+                 'navigator.mediaDevices.getUserMedia');
+    navigator.mediaDevices.getUserMedia(constraints).then(onSuccess, onError);
+  };
+};
+
+},{"../utils":10}],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.
+ */
+'use strict';
+var safariShim = {
+  // TODO: DrAlex, should be here, double check against LayoutTests
+  // shimOnTrack: function() { },
+
+  // TODO: once the back-end for the mac port is done, add.
+  // TODO: check for webkitGTK+
+  // shimPeerConnection: function() { },
+
+  shimGetUserMedia: function() {
+    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);
+      }
+    }
+  }
+};
+
+// Expose public methods.
+module.exports = {
+  shimGetUserMedia: safariShim.shimGetUserMedia
+  // TODO
+  // shimOnTrack: safariShim.shimOnTrack,
+  // shimPeerConnection: safariShim.shimPeerConnection
+};
+
+},{}],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 logDisabled_ = true;
+
+// Utility methods.
+var utils = {
+  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';
+  },
+
+  log: function() {
+    if (typeof window === 'object') {
+      if (logDisabled_) {
+        return;
+      }
+      if (typeof console !== 'undefined' && typeof console.log === 'function') {
+        console.log.apply(console, arguments);
+      }
+    }
+  },
+
+  /**
+   * 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.
+   */
+  extractVersion: function(uastring, expr, pos) {
+    var match = uastring.match(expr);
+    return match && match.length >= pos && parseInt(match[pos], 10);
+  },
+
+  /**
+   * Browser detector.
+   *
+   * @return {object} result containing browser and version
+   *     properties.
+   */
+  detectBrowser: function() {
+    // 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;
+    }
+
+    // Firefox.
+    if (navigator.mozGetUserMedia) {
+      result.browser = 'firefox';
+      result.version = this.extractVersion(navigator.userAgent,
+          /Firefox\/(\d+)\./, 1);
+    } else if (navigator.webkitGetUserMedia) {
+      // Chrome, Chromium, Webview, Opera, all use the chrome shim for now
+      if (window.webkitRTCPeerConnection) {
+        result.browser = 'chrome';
+        result.version = this.extractVersion(navigator.userAgent,
+          /Chrom(e|ium)\/(\d+)\./, 2);
+      } else { // Safari (in an unpublished version) or unknown webkit-based.
+        if (navigator.userAgent.match(/Version\/(\d+).(\d+)/)) {
+          result.browser = 'safari';
+          result.version = this.extractVersion(navigator.userAgent,
+            /AppleWebKit\/(\d+)\./, 1);
+        } else { // unknown webkit-based browser.
+          result.browser = 'Unsupported webkit-based browser ' +
+              'with GUM support but no WebRTC support.';
+          return result;
+        }
+      }
+    } else if (navigator.mediaDevices &&
+        navigator.userAgent.match(/Edge\/(\d+).(\d+)$/)) { // Edge.
+      result.browser = 'edge';
+      result.version = this.extractVersion(navigator.userAgent,
+          /Edge\/(\d+).(\d+)$/, 2);
+    } else if (navigator.mediaDevices &&
+        navigator.userAgent.match(/AppleWebKit\/(\d+)\./)) {
+        // Safari, with webkitGetUserMedia removed.
+      result.browser = 'safari';
+      result.version = this.extractVersion(navigator.userAgent,
+          /AppleWebKit\/(\d+)\./, 1);
+    } else { // Default fallthrough: not supported.
+      result.browser = 'Not a supported browser.';
+      return result;
+    }
+
+    return result;
+  },
+
+  // shimCreateObjectURL must be called before shimSourceObject to avoid loop.
+
+  shimCreateObjectURL: function() {
+    if (!(typeof window === 'object' && window.HTMLMediaElement &&
+          'srcObject' in window.HTMLMediaElement.prototype)) {
+      // 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);
+        console.log('URL.createObjectURL(stream) is deprecated! ' +
+                    'Use elem.srcObject = stream instead!');
+        return url;
+      }
+      return nativeCreateObjectURL(stream);
+    };
+    URL.revokeObjectURL = function(url) {
+      nativeRevokeObjectURL(url);
+      streams.delete(url);
+    };
+
+    var dsc = Object.getOwnPropertyDescriptor(window.HTMLMediaElement.prototype,
+                                              'src');
+    Object.defineProperty(window.HTMLMediaElement.prototype, 'src', {
+      get: function() {
+        return dsc.get.apply(this);
+      },
+      set: function(url) {
+        this.srcObject = streams.get(url) || null;
+        return dsc.set.apply(this, [url]);
+      }
+    });
+
+    var nativeSetAttribute = HTMLMediaElement.prototype.setAttribute;
+    HTMLMediaElement.prototype.setAttribute = function() {
+      if (arguments.length === 2 &&
+          ('' + arguments[0]).toLowerCase() === 'src') {
+        this.srcObject = streams.get(arguments[1]) || null;
+      }
+      return nativeSetAttribute.apply(this, arguments);
+    };
+  }
+};
+
+// Export.
+module.exports = {
+  log: utils.log,
+  disableLog: utils.disableLog,
+  browserDetails: utils.detectBrowser(),
+  extractVersion: utils.extractVersion,
+  shimCreateObjectURL: utils.shimCreateObjectURL,
+  detectBrowser: utils.detectBrowser.bind(utils)
+};
+
+},{}]},{},[2])(2)
+});