gecko-dev/dom/media/PeerConnection.js

/* jshint moz:true, browser:true */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;

Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "PeerConnectionIdp",
  "resource://gre/modules/media/PeerConnectionIdp.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "convertToRTCStatsReport",
  "resource://gre/modules/media/RTCStatsReport.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "AppConstants",
  "resource://gre/modules/AppConstants.jsm");

const PC_CONTRACT = "@mozilla.org/dom/peerconnection;1";
const PC_OBS_CONTRACT = "@mozilla.org/dom/peerconnectionobserver;1";
const PC_ICE_CONTRACT = "@mozilla.org/dom/rtcicecandidate;1";
const PC_SESSION_CONTRACT = "@mozilla.org/dom/rtcsessiondescription;1";
const PC_MANAGER_CONTRACT = "@mozilla.org/dom/peerconnectionmanager;1";
const PC_STATS_CONTRACT = "@mozilla.org/dom/rtcstatsreport;1";
const PC_STATIC_CONTRACT = "@mozilla.org/dom/peerconnectionstatic;1";
const PC_SENDER_CONTRACT = "@mozilla.org/dom/rtpsender;1";
const PC_RECEIVER_CONTRACT = "@mozilla.org/dom/rtpreceiver;1";
const PC_COREQUEST_CONTRACT = "@mozilla.org/dom/createofferrequest;1";
const PC_DTMF_SENDER_CONTRACT = "@mozilla.org/dom/rtcdtmfsender;1";

const PC_CID = Components.ID("{bdc2e533-b308-4708-ac8e-a8bfade6d851}");
const PC_OBS_CID = Components.ID("{d1748d4c-7f6a-4dc5-add6-d55b7678537e}");
const PC_ICE_CID = Components.ID("{02b9970c-433d-4cc2-923d-f7028ac66073}");
const PC_SESSION_CID = Components.ID("{1775081b-b62d-4954-8ffe-a067bbf508a7}");
const PC_MANAGER_CID = Components.ID("{7293e901-2be3-4c02-b4bd-cbef6fc24f78}");
const PC_STATS_CID = Components.ID("{7fe6e18b-0da3-4056-bf3b-440ef3809e06}");
const PC_STATIC_CID = Components.ID("{0fb47c47-a205-4583-a9fc-cbadf8c95880}");
const PC_SENDER_CID = Components.ID("{4fff5d46-d827-4cd4-a970-8fd53977440e}");
const PC_RECEIVER_CID = Components.ID("{d974b814-8fde-411c-8c45-b86791b81030}");
const PC_COREQUEST_CID = Components.ID("{74b2122d-65a8-4824-aa9e-3d664cb75dc2}");
const PC_DTMF_SENDER_CID = Components.ID("{3610C242-654E-11E6-8EC0-6D1BE389A607}");

function logMsg(msg, file, line, flag, winID) {
  let scriptErrorClass = Cc["@mozilla.org/scripterror;1"];
  let scriptError = scriptErrorClass.createInstance(Ci.nsIScriptError);
  scriptError.initWithWindowID(msg, file, null, line, 0, flag,
                               "content javascript", winID);
  let console = Cc["@mozilla.org/consoleservice;1"].
  getService(Ci.nsIConsoleService);
  console.logMessage(scriptError);
};

// Global list of PeerConnection objects, so they can be cleaned up when
// a page is torn down. (Maps inner window ID to an array of PC objects).
function GlobalPCList() {
  this._list = {};
  this._networkdown = false; // XXX Need to query current state somehow
  this._lifecycleobservers = {};
  this._nextId = 1;
  Services.obs.addObserver(this, "inner-window-destroyed", true);
  Services.obs.addObserver(this, "profile-change-net-teardown", true);
  Services.obs.addObserver(this, "network:offline-about-to-go-offline", true);
  Services.obs.addObserver(this, "network:offline-status-changed", true);
  Services.obs.addObserver(this, "gmp-plugin-crash", true);
  Services.obs.addObserver(this, "PeerConnection:response:allow", true);
  Services.obs.addObserver(this, "PeerConnection:response:deny", true);
  if (Cc["@mozilla.org/childprocessmessagemanager;1"]) {
    let mm = Cc["@mozilla.org/childprocessmessagemanager;1"].getService(Ci.nsIMessageListenerManager);
    mm.addMessageListener("gmp-plugin-crash", this);
  }
}
GlobalPCList.prototype = {
  QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver,
                                         Ci.nsIMessageListener,
                                         Ci.nsISupportsWeakReference,
                                         Ci.IPeerConnectionManager]),
  classID: PC_MANAGER_CID,
  _xpcom_factory: {
    createInstance: function(outer, iid) {
      if (outer) {
        throw Cr.NS_ERROR_NO_AGGREGATION;
      }
      return _globalPCList.QueryInterface(iid);
    }
  },

  notifyLifecycleObservers: function(pc, type) {
    for (var key of Object.keys(this._lifecycleobservers)) {
      this._lifecycleobservers[key](pc, pc._winID, type);
    }
  },

  addPC: function(pc) {
    let winID = pc._winID;
    if (this._list[winID]) {
      this._list[winID].push(Cu.getWeakReference(pc));
    } else {
      this._list[winID] = [Cu.getWeakReference(pc)];
    }
    pc._globalPCListId = this._nextId++;
    this.removeNullRefs(winID);
  },

  findPC: function(globalPCListId) {
    for (let winId in this._list) {
      if (this._list.hasOwnProperty(winId)) {
        for (let pcref of this._list[winId]) {
          let pc = pcref.get();
          if (pc && pc._globalPCListId == globalPCListId) {
            return pc;
          }
        }
      }
    }
  },

  removeNullRefs: function(winID) {
    if (this._list[winID] === undefined) {
      return;
    }
    this._list[winID] = this._list[winID].filter(
      function (e,i,a) { return e.get() !== null; });

    if (this._list[winID].length === 0) {
      delete this._list[winID];
    }
  },

  hasActivePeerConnection: function(winID) {
    this.removeNullRefs(winID);
    return this._list[winID] ? true : false;
  },

  handleGMPCrash: function(data) {
    let broadcastPluginCrash = function(list, winID, pluginID, pluginName) {
      if (list.hasOwnProperty(winID)) {
        list[winID].forEach(function(pcref) {
          let pc = pcref.get();
          if (pc) {
            pc._pc.pluginCrash(pluginID, pluginName);
          }
        });
      }
    };

    // a plugin crashed; if it's associated with any of our PCs, fire an
    // event to the DOM window
    for (let winId in this._list) {
      broadcastPluginCrash(this._list, winId, data.pluginID, data.pluginName);
    }
  },

  receiveMessage: function(message) {
    if (message.name == "gmp-plugin-crash") {
      this.handleGMPCrash(message.data);
    }
  },

  observe: function(subject, topic, data) {
    let cleanupPcRef = function(pcref) {
      let pc = pcref.get();
      if (pc) {
        pc._pc.close();
        delete pc._observer;
        pc._pc = null;
      }
    };

    let cleanupWinId = function(list, winID) {
      if (list.hasOwnProperty(winID)) {
        list[winID].forEach(cleanupPcRef);
        delete list[winID];
      }
    };

    if (topic == "inner-window-destroyed") {
      let winID = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
      cleanupWinId(this._list, winID);

      if (this._lifecycleobservers.hasOwnProperty(winID)) {
        delete this._lifecycleobservers[winID];
      }
    } else if (topic == "profile-change-net-teardown" ||
               topic == "network:offline-about-to-go-offline") {
      // Delete all peerconnections on shutdown - mostly synchronously (we
      // need them to be done deleting transports and streams before we
      // return)! All socket operations must be queued to STS thread
      // before we return to here.
      // Also kill them if "Work Offline" is selected - more can be created
      // while offline, but attempts to connect them should fail.
      for (let winId in this._list) {
        cleanupWinId(this._list, winId);
      }
      this._networkdown = true;
    }
    else if (topic == "network:offline-status-changed") {
      if (data == "offline") {
        // this._list shold be empty here
        this._networkdown = true;
      } else if (data == "online") {
        this._networkdown = false;
      }
    } else if (topic == "gmp-plugin-crash") {
      if (subject instanceof Ci.nsIWritablePropertyBag2) {
        let pluginID = subject.getPropertyAsUint32("pluginID");
        let pluginName = subject.getPropertyAsAString("pluginName");
        let data = { pluginID, pluginName };
        this.handleGMPCrash(data);
      }
    } else if (topic == "PeerConnection:response:allow" ||
               topic == "PeerConnection:response:deny") {
      var pc = this.findPC(data);
      if (pc) {
        if (topic == "PeerConnection:response:allow") {
          pc._settlePermission.allow();
        } else {
          let err = new pc._win.DOMException("The request is not allowed by " +
              "the user agent or the platform in the current context.",
              "NotAllowedError");
          pc._settlePermission.deny(err);
        }
      }
    }
  },

  _registerPeerConnectionLifecycleCallback: function(winID, cb) {
    this._lifecycleobservers[winID] = cb;
  },
};
var _globalPCList = new GlobalPCList();

function RTCIceCandidate() {
  this.candidate = this.sdpMid = this.sdpMLineIndex = null;
}
RTCIceCandidate.prototype = {
  classDescription: "RTCIceCandidate",
  classID: PC_ICE_CID,
  contractID: PC_ICE_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports,
                                         Ci.nsIDOMGlobalPropertyInitializer]),

  init: function(win) { this._win = win; },

  __init: function(dict) {
    this.candidate = dict.candidate;
    this.sdpMid = dict.sdpMid;
    this.sdpMLineIndex = ("sdpMLineIndex" in dict)? dict.sdpMLineIndex : null;
  }
};

function RTCSessionDescription() {}
RTCSessionDescription.prototype = {
  classDescription: "RTCSessionDescription",
  classID: PC_SESSION_CID,
  contractID: PC_SESSION_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports,
                                         Ci.nsIDOMGlobalPropertyInitializer]),

  init: function(win) {
    this._win = win;
    this._winID = this._win.QueryInterface(Ci.nsIInterfaceRequestor)
    .getInterface(Ci.nsIDOMWindowUtils).currentInnerWindowID;
  },

  __init: function({ type, sdp }) {
    Object.assign(this, { _type: type, _sdp: sdp });
  },

  get type() { return this._type; },
  set type(type) {
    this.warn();
    this._type = type;
  },

  get sdp() { return this._sdp; },
  set sdp(sdp) {
    this.warn();
    this._sdp = sdp;
  },

  warn: function() {
    if (!this._warned) {
      // Warn once per RTCSessionDescription about deprecated writable usage.
      this.logWarning("RTCSessionDescription's members are readonly! " +
                      "Writing to them is deprecated and will break soon!");
      this._warned = true;
    }
  },

  logWarning: function(msg) {
    let err = this._win.Error();
    logMsg(msg, err.fileName, err.lineNumber, Ci.nsIScriptError.warningFlag,
           this._winID);
  }
};

function RTCStatsReport(win, dict) {
  this._win = win;
  this._pcid = dict.pcid;
  this._report = convertToRTCStatsReport(dict);
}
RTCStatsReport.prototype = {
  classDescription: "RTCStatsReport",
  classID: PC_STATS_CID,
  contractID: PC_STATS_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),

  setInternal: function(aKey, aObj) {
    return this.__DOM_IMPL__.__set(aKey, aObj);
  },

  // TODO: Remove legacy API eventually
  //
  // Since maplike is recent, we still also make the stats available as legacy
  // enumerable read-only properties directly on our content-facing object.
  // Must be called after our webidl sandwich is made.

  makeStatsPublic: function(warnNullable) {
    let legacyProps = {};
    for (let key in this._report) {
      let value = Cu.cloneInto(this._report[key], this._win);
      this.setInternal(key, value);

      legacyProps[key] = {
        enumerable: true, configurable: false,
        get: Cu.exportFunction(function() {
          if (warnNullable.warn) {
            warnNullable.warn();
            warnNullable.warn = null;
          }
          return value;
        }, this.__DOM_IMPL__.wrappedJSObject)
      };
    }
    Object.defineProperties(this.__DOM_IMPL__.wrappedJSObject, legacyProps);
  },

  get mozPcid() { return this._pcid; }
};

function RTCPeerConnection() {
  this._senders = [];
  this._receivers = [];

  this._pc = null;
  this._observer = null;
  this._closed = false;

  this._onCreateOfferSuccess = null;
  this._onCreateOfferFailure = null;
  this._onCreateAnswerSuccess = null;
  this._onCreateAnswerFailure = null;
  this._onGetStatsSuccess = null;
  this._onGetStatsFailure = null;
  this._onReplaceTrackSender = null;
  this._onReplaceTrackWithTrack = null;
  this._onReplaceTrackSuccess = null;
  this._onReplaceTrackFailure = null;

  this._localType = null;
  this._remoteType = null;
  // http://rtcweb-wg.github.io/jsep/#rfc.section.4.1.9
  // canTrickle == null means unknown; when a remote description is received it
  // is set to true or false based on the presence of the "trickle" ice-option
  this._canTrickle = null;

  // States
  this._iceGatheringState = this._iceConnectionState = "new";
}
RTCPeerConnection.prototype = {
  classDescription: "RTCPeerConnection",
  classID: PC_CID,
  contractID: PC_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports,
                                         Ci.nsIDOMGlobalPropertyInitializer]),
  init: function(win) { this._win = win; },

  __init: function(rtcConfig) {
    this._winID = this._win.QueryInterface(Ci.nsIInterfaceRequestor)
    .getInterface(Ci.nsIDOMWindowUtils).currentInnerWindowID;
    // TODO: Update this code once we support pc.setConfiguration, to track
    // setting from content independently from pref (Bug 1181768).
    if (rtcConfig.iceTransportPolicy == "all" &&
        Services.prefs.getBoolPref("media.peerconnection.ice.relay_only")) {
      rtcConfig.iceTransportPolicy = "relay";
    }
    this._config = Object.assign({}, rtcConfig);

    if (!rtcConfig.iceServers ||
        !Services.prefs.getBoolPref("media.peerconnection.use_document_iceservers")) {
      try {
         rtcConfig.iceServers =
           JSON.parse(Services.prefs.getCharPref("media.peerconnection.default_iceservers") || "[]");
      } catch (e) {
        this.logWarning(
            "Ignoring invalid media.peerconnection.default_iceservers in about:config");
        rtcConfig.iceServers = [];
      }
      try {
        this._mustValidateRTCConfiguration(rtcConfig,
            "Ignoring invalid media.peerconnection.default_iceservers in about:config");
      } catch (e) {
        this.logWarning(e.message);
        rtcConfig.iceServers = [];
      }
    } else {
      // This gets executed in the typical case when iceServers
      // are passed in through the web page.
      this._mustValidateRTCConfiguration(rtcConfig,
        "RTCPeerConnection constructor passed invalid RTCConfiguration");
    }
    var principal = Cu.getWebIDLCallerPrincipal();
    this._isChrome = Services.scriptSecurityManager.isSystemPrincipal(principal);

    if (_globalPCList._networkdown) {
      throw new this._win.DOMException(
          "Can't create RTCPeerConnections when the network is down",
          "InvalidStateError");
    }

    this.makeGetterSetterEH("ontrack");
    this.makeLegacyGetterSetterEH("onaddstream", "Use peerConnection.ontrack instead.");
    this.makeLegacyGetterSetterEH("onaddtrack", "Use peerConnection.ontrack instead.");
    this.makeGetterSetterEH("onicecandidate");
    this.makeGetterSetterEH("onnegotiationneeded");
    this.makeGetterSetterEH("onsignalingstatechange");
    this.makeGetterSetterEH("onremovestream");
    this.makeGetterSetterEH("ondatachannel");
    this.makeGetterSetterEH("oniceconnectionstatechange");
    this.makeGetterSetterEH("onicegatheringstatechange");
    this.makeGetterSetterEH("onidentityresult");
    this.makeGetterSetterEH("onpeeridentity");
    this.makeGetterSetterEH("onidpassertionerror");
    this.makeGetterSetterEH("onidpvalidationerror");

    this._pc = new this._win.PeerConnectionImpl();
    this._operationsChain = this._win.Promise.resolve();

    this.__DOM_IMPL__._innerObject = this;
    this._observer = new this._win.PeerConnectionObserver(this.__DOM_IMPL__);

    var location = "" + this._win.location;

    // Warn just once per PeerConnection about deprecated getStats usage.
    this._warnDeprecatedStatsAccessNullable = { warn: () =>
      this.logWarning("non-maplike pc.getStats access is deprecated! " +
                      "See http://w3c.github.io/webrtc-pc/#example for usage.") };

    // Add a reference to the PeerConnection to global list (before init).
    _globalPCList.addPC(this);

    this._impl.initialize(this._observer, this._win, rtcConfig,
                          Services.tm.currentThread);
    this._initCertificate(rtcConfig.certificates);
    this._initIdp();
    _globalPCList.notifyLifecycleObservers(this, "initialized");
  },

  get _impl() {
    if (!this._pc) {
      throw new this._win.DOMException(
          "RTCPeerConnection is gone (did you enter Offline mode?)",
          "InvalidStateError");
    }
    return this._pc;
  },

  getConfiguration: function() {
    return this._config;
  },

  _initCertificate: function(certificates) {
    let certPromise;
    if (certificates && certificates.length > 0) {
      if (certificates.length > 1) {
        throw new this._win.DOMException(
          "RTCPeerConnection does not currently support multiple certificates",
          "NotSupportedError");
      }
      let cert = certificates.find(c => c.expires > Date.now());
      if (!cert) {
        throw new this._win.DOMException(
          "Unable to create RTCPeerConnection with an expired certificate",
          "InvalidParameterError");
      }
      certPromise = Promise.resolve(cert);
    } else {
      certPromise = this._win.RTCPeerConnection.generateCertificate({
        name: "ECDSA", namedCurve: "P-256"
      });
    }
    this._certificateReady = certPromise
      .then(cert => this._impl.certificate = cert);
  },

  _initIdp: function() {
    this._peerIdentity = new this._win.Promise((resolve, reject) => {
      this._resolvePeerIdentity = resolve;
      this._rejectPeerIdentity = reject;
    });
    this._lastIdentityValidation = this._win.Promise.resolve();

    let prefName = "media.peerconnection.identity.timeout";
    let idpTimeout = Services.prefs.getIntPref(prefName);
    this._localIdp = new PeerConnectionIdp(this._win, idpTimeout);
    this._remoteIdp = new PeerConnectionIdp(this._win, idpTimeout);
  },

  // Add a function to the internal operations chain.

  _chain: function(func) {
    this._checkClosed(); // out here DOMException line-numbers work.
    let p = this._operationsChain.then(() => {
      // Don't _checkClosed() inside the chain, because it throws, and spec
      // behavior as of this writing is to NOT reject outstanding promises on
      // close. This is what happens most of the time anyways, as the c++ code
      // stops calling us once closed, hanging the chain. However, c++ may
      // already have queued tasks on us, so if we're one of those then sit back.
      if (!this._closed) {
        return func();
      }
    });
    // don't propagate errors in the operations chain (this is a fork of p).
    this._operationsChain = p.catch(() => {});
    return p;
  },

  // This wrapper helps implement legacy callbacks in a manner that produces
  // correct line-numbers in errors, provided that methods validate their inputs
  // before putting themselves on the pc's operations chain.
  //
  // It also serves as guard against settling promises past close().

  _legacyCatchAndCloseGuard: function(onSuccess, onError, func) {
    if (!onSuccess) {
      return func().then(v => (this._closed ? new Promise(() => {}) : v),
                         e => (this._closed ? new Promise(() => {}) : Promise.reject(e)));
    }
    try {
      return func().then(this._wrapLegacyCallback(onSuccess),
                         this._wrapLegacyCallback(onError));
    } catch (e) {
      this._wrapLegacyCallback(onError)(e);
      return this._win.Promise.resolve(); // avoid webidl TypeError
    }
  },

  _wrapLegacyCallback: function(func) {
    return result => {
      try {
        func && func(result);
      } catch (e) {
        this.logErrorAndCallOnError(e);
      }
    };
  },

  /**
   * An RTCConfiguration may look like this:
   *
   * { "iceServers": [ { urls: "stun:stun.example.org", },
   *                   { url: "stun:stun.example.org", }, // deprecated version
   *                   { urls: ["turn:turn1.x.org", "turn:turn2.x.org"],
   *                     username:"jib", credential:"mypass"} ] }
   *
   * This function normalizes the structure of the input for rtcConfig.iceServers for us,
   * so we test well-formed stun/turn urls before passing along to C++.
   *   msg - Error message to detail which array-entry failed, if any.
   */
  _mustValidateRTCConfiguration: function(rtcConfig, msg) {

    // Normalize iceServers input
    rtcConfig.iceServers.forEach(server => {
      if (typeof server.urls === "string") {
        server.urls = [server.urls];
      } else if (!server.urls && server.url) {
        // TODO: Remove support for legacy iceServer.url eventually (Bug 1116766)
        server.urls = [server.url];
        this.logWarning("RTCIceServer.url is deprecated! Use urls instead.");
      }
    });

    let ios = Cc['@mozilla.org/network/io-service;1'].getService(Ci.nsIIOService);

    let nicerNewURI = uriStr => {
      try {
        return ios.newURI(uriStr, null, null);
      } catch (e if (e.result == Cr.NS_ERROR_MALFORMED_URI)) {
        throw new this._win.DOMException(msg + " - malformed URI: " + uriStr,
                                         "SyntaxError");
      }
    };

    rtcConfig.iceServers.forEach(server => {
      if (!server.urls) {
        throw new this._win.DOMException(msg + " - missing urls", "InvalidAccessError");
      }
      server.urls.forEach(urlStr => {
        let url = nicerNewURI(urlStr);
        if (url.scheme in { turn:1, turns:1 }) {
          if (server.username == undefined) {
            throw new this._win.DOMException(msg + " - missing username: " + urlStr,
                                             "InvalidAccessError");
          }
          if (server.credential == undefined) {
            throw new this._win.DOMException(msg + " - missing credential: " + urlStr,
                                             "InvalidAccessError");
          }
          if (server.credentialType != "password") {
            this.logWarning("RTCConfiguration TURN credentialType \""+
                            server.credentialType +
                            "\" is not yet implemented. Treating as password."+
                            " https://bugzil.la/1247616");
          }
        }
        else if (!(url.scheme in { stun:1, stuns:1 })) {
          throw new this._win.DOMException(msg + " - improper scheme: " + url.scheme,
                                           "SyntaxError");
        }
        if (url.scheme in { stuns:1, turns:1 }) {
          this.logWarning(url.scheme.toUpperCase() + " is not yet supported.");
        }
      });
    });
  },

  // Ideally, this should be of the form _checkState(state),
  // where the state is taken from an enumeration containing
  // the valid peer connection states defined in the WebRTC
  // spec. See Bug 831756.
  _checkClosed: function() {
    if (this._closed) {
      throw new this._win.DOMException("Peer connection is closed",
                                       "InvalidStateError");
    }
  },

  dispatchEvent: function(event) {
    // PC can close while events are firing if there is an async dispatch
    // in c++ land. But let through "closed" signaling and ice connection events.
    if (!this._closed || this._inClose) {
      this.__DOM_IMPL__.dispatchEvent(event);
    }
  },

  // Log error message to web console and window.onerror, if present.
  logErrorAndCallOnError: function(e) {
    this.logMsg(e.message, e.fileName, e.lineNumber, Ci.nsIScriptError.exceptionFlag);

    // Safely call onerror directly if present (necessary for testing)
    try {
      if (typeof this._win.onerror === "function") {
        this._win.onerror(e.message, e.fileName, e.lineNumber);
      }
    } catch(e) {
      // If onerror itself throws, service it.
      try {
        this.logMsg(e.message, e.fileName, e.lineNumber, Ci.nsIScriptError.errorFlag);
      } catch(e) {}
    }
  },

  logError: function(msg) {
    this.logStackMsg(msg, Ci.nsIScriptError.errorFlag);
  },

  logWarning: function(msg) {
    this.logStackMsg(msg, Ci.nsIScriptError.warningFlag);
  },

  logStackMsg: function(msg, flag) {
    let err = this._win.Error();
    this.logMsg(msg, err.fileName, err.lineNumber, flag);
  },

  logMsg: function(msg, file, line, flag) {
    return logMsg(msg, file, line, flag, this._winID);
  },

  getEH: function(type) {
    return this.__DOM_IMPL__.getEventHandler(type);
  },

  setEH: function(type, handler) {
    this.__DOM_IMPL__.setEventHandler(type, handler);
  },

  makeGetterSetterEH: function(name) {
    Object.defineProperty(this, name,
                          {
                            get:function()  { return this.getEH(name); },
                            set:function(h) { return this.setEH(name, h); }
                          });
  },

  makeLegacyGetterSetterEH: function(name, msg) {
    Object.defineProperty(this, name,
                          {
                            get:function()  { return this.getEH(name); },
                            set:function(h) {
                              this.logWarning(name + " is deprecated! " + msg);
                              return this.setEH(name, h);
                            }
                          });
  },

  _addIdentityAssertion: function(sdpPromise, origin) {
    if (!this._localIdp.enabled) {
      return sdpPromise;
    }
    return Promise.all([
      this._certificateReady
        .then(() => this._localIdp.getIdentityAssertion(this._impl.fingerprint,
                                                        origin)),
      sdpPromise
    ]).then(([,sdp]) => this._localIdp.addIdentityAttribute(sdp));
  },

  createOffer: function(optionsOrOnSuccess, onError, options) {
    // This entry-point handles both new and legacy call sig. Decipher which one
    let onSuccess;
    if (typeof optionsOrOnSuccess == "function") {
      onSuccess = optionsOrOnSuccess;
    } else {
      options = optionsOrOnSuccess;
    }
    return this._legacyCatchAndCloseGuard(onSuccess, onError, () => {
      let origin = Cu.getWebIDLCallerPrincipal().origin;
      return this._chain(() => {
        let p = Promise.all([this.getPermission(), this._certificateReady])
          .then(() => new this._win.Promise((resolve, reject) => {
            this._onCreateOfferSuccess = resolve;
            this._onCreateOfferFailure = reject;
            this._impl.createOffer(options);
          }));
        p = this._addIdentityAssertion(p, origin);
        return p.then(
          sdp => new this._win.RTCSessionDescription({ type: "offer", sdp: sdp }));
      });
    });
  },

  createAnswer: function(optionsOrOnSuccess, onError) {
    // This entry-point handles both new and legacy call sig. Decipher which one
    let onSuccess, options;
    if (typeof optionsOrOnSuccess == "function") {
      onSuccess = optionsOrOnSuccess;
    } else {
      options = optionsOrOnSuccess;
    }
    return this._legacyCatchAndCloseGuard(onSuccess, onError, () => {
      let origin = Cu.getWebIDLCallerPrincipal().origin;
      return this._chain(() => {
        let p = Promise.all([this.getPermission(), this._certificateReady])
          .then(() => new this._win.Promise((resolve, reject) => {
            // We give up line-numbers in errors by doing this here, but do all
            // state-checks inside the chain, to support the legacy feature that
            // callers don't have to wait for setRemoteDescription to finish.
            if (!this.remoteDescription) {
              throw new this._win.DOMException("setRemoteDescription not called",
                                               "InvalidStateError");
            }
            if (this.remoteDescription.type != "offer") {
              throw new this._win.DOMException("No outstanding offer",
                                               "InvalidStateError");
            }
            this._onCreateAnswerSuccess = resolve;
            this._onCreateAnswerFailure = reject;
            this._impl.createAnswer();
          }));
        p = this._addIdentityAssertion(p, origin);
        return p.then(sdp => {
          return new this._win.RTCSessionDescription({ type: "answer", sdp: sdp });
        });
      });
    });
  },

  getPermission: function() {
    if (this._havePermission) {
      return this._havePermission;
    }
    if (this._isChrome ||
        AppConstants.MOZ_B2G ||
        Services.prefs.getBoolPref("media.navigator.permission.disabled")) {
      return this._havePermission = Promise.resolve();
    }
    return this._havePermission = new Promise((resolve, reject) => {
      this._settlePermission = { allow: resolve, deny: reject };
      let outerId = this._win.QueryInterface(Ci.nsIInterfaceRequestor).
          getInterface(Ci.nsIDOMWindowUtils).outerWindowID;

      let chrome = new CreateOfferRequest(outerId, this._winID,
                                                 this._globalPCListId, false);
      let request = this._win.CreateOfferRequest._create(this._win, chrome);
      Services.obs.notifyObservers(request, "PeerConnection:request", null);
    });
  },

  setLocalDescription: function(desc, onSuccess, onError) {
    return this._legacyCatchAndCloseGuard(onSuccess, onError, () => {
      this._localType = desc.type;

      let type;
      switch (desc.type) {
        case "offer":
          type = Ci.IPeerConnection.kActionOffer;
          break;
        case "answer":
          type = Ci.IPeerConnection.kActionAnswer;
          break;
        case "pranswer":
          throw new this._win.DOMException("pranswer not yet implemented",
                                           "NotSupportedError");
        case "rollback":
          type = Ci.IPeerConnection.kActionRollback;
          break;
        default:
          throw new this._win.DOMException(
              "Invalid type " + desc.type + " provided to setLocalDescription",
              "InvalidParameterError");
      }

      if (desc.type !== "rollback" && !desc.sdp) {
        throw new this._win.DOMException(
            "Empty or null SDP provided to setLocalDescription",
            "InvalidParameterError");
      }

      return this._chain(() => this.getPermission()
          .then(() => new this._win.Promise((resolve, reject) => {
        this._onSetLocalDescriptionSuccess = resolve;
        this._onSetLocalDescriptionFailure = reject;
        this._impl.setLocalDescription(type, desc.sdp);
      })));
    });
  },

  _validateIdentity: function(sdp, origin) {
    let expectedIdentity;

    // Only run a single identity verification at a time.  We have to do this to
    // avoid problems with the fact that identity validation doesn't block the
    // resolution of setRemoteDescription().
    let validation = this._lastIdentityValidation
      .then(() => this._remoteIdp.verifyIdentityFromSDP(sdp, origin))
      .then(msg => {
        expectedIdentity = this._impl.peerIdentity;
        // If this pc has an identity already, then the identity in sdp must match
        if (expectedIdentity && (!msg || msg.identity !== expectedIdentity)) {
          this.close();
          throw new this._win.DOMException(
            "Peer Identity mismatch, expected: " + expectedIdentity,
            "IncompatibleSessionDescriptionError");
        }
        if (msg) {
          // Set new identity and generate an event.
          this._impl.peerIdentity = msg.identity;
          this._resolvePeerIdentity(Cu.cloneInto({
            idp: this._remoteIdp.provider,
            name: msg.identity
          }, this._win));
        }
      })
      .catch(e => {
        this._rejectPeerIdentity(e);
        // If we don't expect a specific peer identity, failure to get a valid
        // peer identity is not a terminal state, so replace the promise to
        // allow another attempt.
        if (!this._impl.peerIdentity) {
          this._peerIdentity = new this._win.Promise((resolve, reject) => {
            this._resolvePeerIdentity = resolve;
            this._rejectPeerIdentity = reject;
          });
        }
        throw e;
      });
    this._lastIdentityValidation = validation.catch(() => {});

    // Only wait for IdP validation if we need identity matching
    return expectedIdentity ? validation : this._win.Promise.resolve();
  },

  setRemoteDescription: function(desc, onSuccess, onError) {
    return this._legacyCatchAndCloseGuard(onSuccess, onError, () => {
      this._remoteType = desc.type;

      let type;
      switch (desc.type) {
        case "offer":
          type = Ci.IPeerConnection.kActionOffer;
          break;
        case "answer":
          type = Ci.IPeerConnection.kActionAnswer;
          break;
        case "pranswer":
          throw new this._win.DOMException("pranswer not yet implemented",
                                           "NotSupportedError");
        case "rollback":
          type = Ci.IPeerConnection.kActionRollback;
          break;
        default:
          throw new this._win.DOMException(
              "Invalid type " + desc.type + " provided to setRemoteDescription",
              "InvalidParameterError");
      }

      if (!desc.sdp && desc.type !== "rollback") {
        throw new this._win.DOMException(
            "Empty or null SDP provided to setRemoteDescription",
            "InvalidParameterError");
      }

      // Get caller's origin before hitting the promise chain
      let origin = Cu.getWebIDLCallerPrincipal().origin;

      return this._chain(() => {
        let setRem = this.getPermission()
          .then(() => new this._win.Promise((resolve, reject) => {
            this._onSetRemoteDescriptionSuccess = resolve;
            this._onSetRemoteDescriptionFailure = reject;
            this._impl.setRemoteDescription(type, desc.sdp);
          })).then(() => { this._updateCanTrickle(); });

        if (desc.type === "rollback") {
          return setRem;
        }

        // Do setRemoteDescription and identity validation in parallel
        let validId = this._validateIdentity(desc.sdp, origin);
        return this._win.Promise.all([setRem, validId])
          .then(() => {}); // must return undefined
      });
    });
  },

  setIdentityProvider: function(provider, protocol, username) {
    this._checkClosed();
    this._localIdp.setIdentityProvider(provider, protocol, username);
  },

  getIdentityAssertion: function() {
    let origin = Cu.getWebIDLCallerPrincipal().origin;
    return this._chain(
      () => this._certificateReady.then(
        () => this._localIdp.getIdentityAssertion(this._impl.fingerprint, origin)
      )
    );
  },

  get canTrickleIceCandidates() {
    return this._canTrickle;
  },

  _updateCanTrickle: function() {
    let containsTrickle = section => {
      let lines = section.toLowerCase().split(/(?:\r\n?|\n)/);
      return lines.some(line => {
        let prefix = "a=ice-options:";
        if (line.substring(0, prefix.length) !== prefix) {
          return false;
        }
        let tokens = line.substring(prefix.length).split(" ");
        return tokens.some(x => x === "trickle");
      });
    };

    let desc = null;
    try {
      // The getter for remoteDescription can throw if the pc is closed.
      desc = this.remoteDescription;
    } catch (e) {}
    if (!desc) {
      this._canTrickle = null;
      return;
    }

    let sections = desc.sdp.split(/(?:\r\n?|\n)m=/);
    let topSection = sections.shift();
    this._canTrickle =
      containsTrickle(topSection) || sections.every(containsTrickle);
  },


  addIceCandidate: function(c, onSuccess, onError) {
    return this._legacyCatchAndCloseGuard(onSuccess, onError, () => {
      if (!c.candidate && !c.sdpMLineIndex) {
        throw new this._win.DOMException("Invalid candidate passed to addIceCandidate!",
                                         "InvalidParameterError");
      }
      return this._chain(() => new this._win.Promise((resolve, reject) => {
        this._onAddIceCandidateSuccess = resolve;
        this._onAddIceCandidateError = reject;
        this._impl.addIceCandidate(c.candidate, c.sdpMid || "", c.sdpMLineIndex);
      }));
    });
  },

  addStream: function(stream) {
    stream.getTracks().forEach(track => this.addTrack(track, stream));
  },

  addTrack: function(track, stream) {
    if (stream.currentTime === undefined) {
      throw new this._win.DOMException("invalid stream.", "InvalidParameterError");
    }
    this._checkClosed();
    this._senders.forEach(sender => {
      if (sender.track == track) {
        throw new this._win.DOMException("already added.",
                                         "InvalidParameterError");
      }
    });
    this._impl.addTrack(track, stream);
    let sender = this._win.RTCRtpSender._create(this._win,
                                                new RTCRtpSender(this, track,
                                                                 stream));
    this._senders.push(sender);
    return sender;
  },

  removeTrack: function(sender) {
    this._checkClosed();
    var i = this._senders.indexOf(sender);
    if (i >= 0) {
      this._senders.splice(i, 1);
      this._impl.removeTrack(sender.track); // fires negotiation needed
    }
  },

  _insertDTMF: function(sender, tones, duration, interToneGap) {
    return this._impl.insertDTMF(sender.__DOM_IMPL__, tones, duration, interToneGap);
  },

  _getDTMFToneBuffer: function(sender) {
    return this._impl.getDTMFToneBuffer(sender.__DOM_IMPL__);
  },

  _replaceTrack: function(sender, withTrack) {
    // TODO: Do a (sender._stream.getTracks().indexOf(track) < 0) check
    //       on both track args someday.
    //
    // The proposed API will be that both tracks must already be in the same
    // stream. However, since our MediaStreams currently are limited to one
    // track per type, we allow replacement with an outside track not already
    // in the same stream.
    //
    // Since a track may be replaced more than once, the track being replaced
    // may not be in the stream either, so we check neither arg right now.

    return new this._win.Promise((resolve, reject) => {
      this._onReplaceTrackSender = sender;
      this._onReplaceTrackWithTrack = withTrack;
      this._onReplaceTrackSuccess = resolve;
      this._onReplaceTrackFailure = reject;
      this._impl.replaceTrack(sender.track, withTrack);
    });
  },

  _setParameters: function(sender, parameters) {
    if (!Services.prefs.getBoolPref("media.peerconnection.simulcast")) {
      return;
    }
    // validate parameters input
    var encodings = parameters.encodings || [];

    encodings.reduce((uniqueRids, encoding) => {
      if (encoding.scaleResolutionDownBy < 1.0) {
        throw new this._win.RangeError("scaleResolutionDownBy must be >= 1.0");
      }
      if (!encoding.rid && encodings.length > 1) {
        throw new this._win.DOMException("Missing rid", "TypeError");
      }
      if (uniqueRids[encoding.rid]) {
        throw new this._win.DOMException("Duplicate rid", "TypeError");
      }
      uniqueRids[encoding.rid] = true;
      return uniqueRids;
    }, {});

    this._impl.setParameters(sender.track, parameters);
  },

  _getParameters: function(sender) {
    if (!Services.prefs.getBoolPref("media.peerconnection.simulcast")) {
      return;
    }
    return this._impl.getParameters(sender.track);
  },

  close: function() {
    if (this._closed) {
      return;
    }
    this._closed = true;
    this._inClose = true;
    this.changeIceConnectionState("closed");
    this._localIdp.close();
    this._remoteIdp.close();
    this._impl.close();
    this._inClose = false;
  },

  getLocalStreams: function() {
    this._checkClosed();
    return this._impl.getLocalStreams();
  },

  getRemoteStreams: function() {
    this._checkClosed();
    return this._impl.getRemoteStreams();
  },

  getSenders: function() {
    return this._senders;
  },

  getReceivers: function() {
    return this._receivers;
  },

  mozSelectSsrc: function(receiver, ssrcIndex) {
    this._impl.selectSsrc(receiver.track, ssrcIndex);
  },

  get localDescription() {
    this._checkClosed();
    let sdp = this._impl.localDescription;
    if (sdp.length == 0) {
      return null;
    }

    return new this._win.RTCSessionDescription({ type: this._localType,
                                                    sdp: sdp });
  },

  get remoteDescription() {
    this._checkClosed();
    let sdp = this._impl.remoteDescription;
    if (sdp.length == 0) {
      return null;
    }
    return new this._win.RTCSessionDescription({ type: this._remoteType,
                                                    sdp: sdp });
  },

  get peerIdentity() { return this._peerIdentity; },
  get idpLoginUrl() { return this._localIdp.idpLoginUrl; },
  get id() { return this._impl.id; },
  set id(s) { this._impl.id = s; },
  get iceGatheringState()  { return this._iceGatheringState; },
  get iceConnectionState() { return this._iceConnectionState; },

  get signalingState() {
    // checking for our local pc closed indication
    // before invoking the pc methods.
    if (this._closed) {
      return "closed";
    }
    return {
      "SignalingInvalid":            "",
      "SignalingStable":             "stable",
      "SignalingHaveLocalOffer":     "have-local-offer",
      "SignalingHaveRemoteOffer":    "have-remote-offer",
      "SignalingHaveLocalPranswer":  "have-local-pranswer",
      "SignalingHaveRemotePranswer": "have-remote-pranswer",
      "SignalingClosed":             "closed"
    }[this._impl.signalingState];
  },

  changeIceGatheringState: function(state) {
    this._iceGatheringState = state;
    _globalPCList.notifyLifecycleObservers(this, "icegatheringstatechange");
    this.dispatchEvent(new this._win.Event("icegatheringstatechange"));
  },

  changeIceConnectionState: function(state) {
    this._iceConnectionState = state;
    _globalPCList.notifyLifecycleObservers(this, "iceconnectionstatechange");
    this.dispatchEvent(new this._win.Event("iceconnectionstatechange"));
  },

  getStats: function(selector, onSuccess, onError) {
    return this._legacyCatchAndCloseGuard(onSuccess, onError, () => {
      return this._chain(() => new this._win.Promise((resolve, reject) => {
        this._onGetStatsSuccess = resolve;
        this._onGetStatsFailure = reject;
        this._impl.getStats(selector);
      }));
    });
  },

  createDataChannel: function(label, dict) {
    this._checkClosed();
    if (dict == undefined) {
      dict = {};
    }
    if (dict.maxRetransmitNum != undefined) {
      dict.maxRetransmits = dict.maxRetransmitNum;
      this.logWarning("Deprecated RTCDataChannelInit dictionary entry maxRetransmitNum used!");
    }
    if (dict.outOfOrderAllowed != undefined) {
      dict.ordered = !dict.outOfOrderAllowed; // the meaning is swapped with
                                              // the name change
      this.logWarning("Deprecated RTCDataChannelInit dictionary entry outOfOrderAllowed used!");
    }

    if (dict.preset != undefined) {
      dict.negotiated = dict.preset;
      this.logWarning("Deprecated RTCDataChannelInit dictionary entry preset used!");
    }
    if (dict.stream != undefined) {
      dict.id = dict.stream;
      this.logWarning("Deprecated RTCDataChannelInit dictionary entry stream used!");
    }

    if (dict.maxRetransmitTime !== null && dict.maxRetransmits !== null) {
      throw new this._win.DOMException(
          "Both maxRetransmitTime and maxRetransmits cannot be provided",
          "InvalidParameterError");
    }
    let protocol;
    if (dict.protocol == undefined) {
      protocol = "";
    } else {
      protocol = dict.protocol;
    }

    // Must determine the type where we still know if entries are undefined.
    let type;
    if (dict.maxRetransmitTime != undefined) {
      type = Ci.IPeerConnection.kDataChannelPartialReliableTimed;
    } else if (dict.maxRetransmits != undefined) {
      type = Ci.IPeerConnection.kDataChannelPartialReliableRexmit;
    } else {
      type = Ci.IPeerConnection.kDataChannelReliable;
    }

    // Synchronous since it doesn't block.
    let channel = this._impl.createDataChannel(
      label, protocol, type, !dict.ordered, dict.maxRetransmitTime,
      dict.maxRetransmits, dict.negotiated ? true : false,
      dict.id != undefined ? dict.id : 0xFFFF
    );
    return channel;
  }
};

// This is a separate object because we don't want to expose it to DOM.
function PeerConnectionObserver() {
  this._dompc = null;
}
PeerConnectionObserver.prototype = {
  classDescription: "PeerConnectionObserver",
  classID: PC_OBS_CID,
  contractID: PC_OBS_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports,
                                         Ci.nsIDOMGlobalPropertyInitializer]),
  init: function(win) { this._win = win; },

  __init: function(dompc) {
    this._dompc = dompc._innerObject;
  },

  newError: function(message, code) {
    // These strings must match those defined in the WebRTC spec.
    const reasonName = [
      "",
      "InternalError",
      "InvalidCandidateError",
      "InvalidParameterError",
      "InvalidStateError",
      "InvalidSessionDescriptionError",
      "IncompatibleSessionDescriptionError",
      "InternalError",
      "IncompatibleMediaStreamTrackError",
      "InternalError"
    ];
    let name = reasonName[Math.min(code, reasonName.length - 1)];
    return new this._dompc._win.DOMException(message, name);
  },

  dispatchEvent: function(event) {
    this._dompc.dispatchEvent(event);
  },

  onCreateOfferSuccess: function(sdp) {
    this._dompc._onCreateOfferSuccess(sdp);
  },

  onCreateOfferError: function(code, message) {
    this._dompc._onCreateOfferFailure(this.newError(message, code));
  },

  onCreateAnswerSuccess: function(sdp) {
    this._dompc._onCreateAnswerSuccess(sdp);
  },

  onCreateAnswerError: function(code, message) {
    this._dompc._onCreateAnswerFailure(this.newError(message, code));
  },

  onSetLocalDescriptionSuccess: function() {
    this._dompc._onSetLocalDescriptionSuccess();
  },

  onSetRemoteDescriptionSuccess: function() {
    this._dompc._onSetRemoteDescriptionSuccess();
  },

  onSetLocalDescriptionError: function(code, message) {
    this._localType = null;
    this._dompc._onSetLocalDescriptionFailure(this.newError(message, code));
  },

  onSetRemoteDescriptionError: function(code, message) {
    this._remoteType = null;
    this._dompc._onSetRemoteDescriptionFailure(this.newError(message, code));
  },

  onAddIceCandidateSuccess: function() {
    this._dompc._onAddIceCandidateSuccess();
  },

  onAddIceCandidateError: function(code, message) {
    this._dompc._onAddIceCandidateError(this.newError(message, code));
  },

  onIceCandidate: function(level, mid, candidate) {
    if (candidate == "") {
      this.foundIceCandidate(null);
    } else {
      this.foundIceCandidate(new this._dompc._win.RTCIceCandidate(
          {
              candidate: candidate,
              sdpMid: mid,
              sdpMLineIndex: level
          }
      ));
    }
  },

  onNegotiationNeeded: function() {
    this.dispatchEvent(new this._win.Event("negotiationneeded"));
  },


  // This method is primarily responsible for updating iceConnectionState.
  // This state is defined in the WebRTC specification as follows:
  //
  // iceConnectionState:
  // -------------------
  //   new           The ICE Agent is gathering addresses and/or waiting for
  //                 remote candidates to be supplied.
  //
  //   checking      The ICE Agent has received remote candidates on at least
  //                 one component, and is checking candidate pairs but has not
  //                 yet found a connection. In addition to checking, it may
  //                 also still be gathering.
  //
  //   connected     The ICE Agent has found a usable connection for all
  //                 components but is still checking other candidate pairs to
  //                 see if there is a better connection. It may also still be
  //                 gathering.
  //
  //   completed     The ICE Agent has finished gathering and checking and found
  //                 a connection for all components. Open issue: it is not
  //                 clear how the non controlling ICE side knows it is in the
  //                 state.
  //
  //   failed        The ICE Agent is finished checking all candidate pairs and
  //                 failed to find a connection for at least one component.
  //                 Connections may have been found for some components.
  //
  //   disconnected  Liveness checks have failed for one or more components.
  //                 This is more aggressive than failed, and may trigger
  //                 intermittently (and resolve itself without action) on a
  //                 flaky network.
  //
  //   closed        The ICE Agent has shut down and is no longer responding to
  //                 STUN requests.

  handleIceConnectionStateChange: function(iceConnectionState) {
    let pc = this._dompc;
    if (pc.iceConnectionState === iceConnectionState) {
      return;
    }
    if (pc.iceConnectionState === 'new') {
      var checking_histogram = Services.telemetry.getHistogramById("WEBRTC_ICE_CHECKING_RATE");
      if (iceConnectionState === 'checking') {
        checking_histogram.add(true);
      } else if (iceConnectionState === 'failed') {
        checking_histogram.add(false);
      }
    } else if (pc.iceConnectionState === 'checking') {
      var success_histogram = Services.telemetry.getHistogramById("WEBRTC_ICE_SUCCESS_RATE");
      if (iceConnectionState === 'completed' ||
          iceConnectionState === 'connected') {
        success_histogram.add(true);
      } else if (iceConnectionState === 'failed') {
        success_histogram.add(false);
      }
    }

    if (iceConnectionState === 'failed') {
      pc.logError("ICE failed, see about:webrtc for more details");
    }

    pc.changeIceConnectionState(iceConnectionState);
  },

  // This method is responsible for updating iceGatheringState. This
  // state is defined in the WebRTC specification as follows:
  //
  // iceGatheringState:
  // ------------------
  //   new        The object was just created, and no networking has occurred
  //              yet.
  //
  //   gathering  The ICE agent is in the process of gathering candidates for
  //              this RTCPeerConnection.
  //
  //   complete   The ICE agent has completed gathering. Events such as adding
  //              a new interface or a new TURN server will cause the state to
  //              go back to gathering.
  //
  handleIceGatheringStateChange: function(gatheringState) {
    let pc = this._dompc;
    if (pc.iceGatheringState === gatheringState) {
      return;
    }
    pc.changeIceGatheringState(gatheringState);
  },

  onStateChange: function(state) {
    switch (state) {
      case "SignalingState":
        this.dispatchEvent(new this._win.Event("signalingstatechange"));
        break;

      case "IceConnectionState":
        this.handleIceConnectionStateChange(this._dompc._pc.iceConnectionState);
        break;

      case "IceGatheringState":
        this.handleIceGatheringStateChange(this._dompc._pc.iceGatheringState);
        break;

      case "SdpState":
        // No-op
        break;

      case "ReadyState":
        // No-op
        break;

      case "SipccState":
        // No-op
        break;

      default:
        this._dompc.logWarning("Unhandled state type: " + state);
        break;
    }
  },

  onGetStatsSuccess: function(dict) {
    let pc = this._dompc;
    let chromeobj = new RTCStatsReport(pc._win, dict);
    let webidlobj = pc._win.RTCStatsReport._create(pc._win, chromeobj);
    chromeobj.makeStatsPublic(pc._warnDeprecatedStatsAccessNullable);
    pc._onGetStatsSuccess(webidlobj);
  },

  onGetStatsError: function(code, message) {
    this._dompc._onGetStatsFailure(this.newError(message, code));
  },

  onAddStream: function(stream) {
    let ev = new this._dompc._win.MediaStreamEvent("addstream",
                                                   { stream: stream });
    this.dispatchEvent(ev);
  },

  onRemoveStream: function(stream) {
    this.dispatchEvent(new this._dompc._win.MediaStreamEvent("removestream",
                                                             { stream: stream }));
  },

  onAddTrack: function(track, streams) {
    let pc = this._dompc;
    let receiver = pc._win.RTCRtpReceiver._create(pc._win,
                                                  new RTCRtpReceiver(this,
                                                                     track));
    pc._receivers.push(receiver);
    let ev = new pc._win.RTCTrackEvent("track",
                                       { receiver: receiver,
                                         track: track,
                                         streams: streams });
    this.dispatchEvent(ev);

    // Fire legacy event as well for a little bit.
    ev = new pc._win.MediaStreamTrackEvent("addtrack", { track: track });
    this.dispatchEvent(ev);
  },

  onRemoveTrack: function(track) {
    let pc = this._dompc;
    let i = pc._receivers.findIndex(receiver => receiver.track == track);
    if (i >= 0) {
      pc._receivers.splice(i, 1);
    }
  },

  onReplaceTrackSuccess: function() {
    var pc = this._dompc;
    pc._onReplaceTrackSender.track = pc._onReplaceTrackWithTrack;
    pc._onReplaceTrackWithTrack = null;
    pc._onReplaceTrackSender = null;
    pc._onReplaceTrackSuccess();
  },

  onReplaceTrackError: function(code, message) {
    var pc = this._dompc;
    pc._onReplaceTrackWithTrack = null;
    pc._onReplaceTrackSender = null;
    pc._onReplaceTrackFailure(this.newError(message, code));
  },

  foundIceCandidate: function(cand) {
    this.dispatchEvent(new this._dompc._win.RTCPeerConnectionIceEvent("icecandidate",
                                                                      { candidate: cand } ));
  },

  notifyDataChannel: function(channel) {
    this.dispatchEvent(new this._dompc._win.RTCDataChannelEvent("datachannel",
                                                                { channel: channel }));
  },

  onDTMFToneChange: function(trackId, tone) {
    var pc = this._dompc;
    var sender = pc._senders.find(sender => sender.track.id == trackId)
    sender.dtmf.dispatchEvent(new pc._win.RTCDTMFToneChangeEvent("tonechange",
                                                                 { tone: tone }));
  }
};

function RTCPeerConnectionStatic() {
}
RTCPeerConnectionStatic.prototype = {
  classDescription: "RTCPeerConnectionStatic",
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports,
                                         Ci.nsIDOMGlobalPropertyInitializer]),

  classID: PC_STATIC_CID,
  contractID: PC_STATIC_CONTRACT,

  init: function(win) {
    this._winID = win.QueryInterface(Ci.nsIInterfaceRequestor)
      .getInterface(Ci.nsIDOMWindowUtils).currentInnerWindowID;
  },

  registerPeerConnectionLifecycleCallback: function(cb) {
    _globalPCList._registerPeerConnectionLifecycleCallback(this._winID, cb);
  },
};

function RTCDTMFSender(sender) {
  this._sender = sender;
}
RTCDTMFSender.prototype = {
  classDescription: "RTCDTMFSender",
  classID: PC_DTMF_SENDER_CID,
  contractID: PC_DTMF_SENDER_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),

  get toneBuffer() {
    return this._sender._pc._getDTMFToneBuffer(this._sender);
  },

  get ontonechange() {
    return this.__DOM_IMPL__.getEventHandler("ontonechange");
  },

  set ontonechange(handler) {
    this.__DOM_IMPL__.setEventHandler("ontonechange", handler);
  },

  insertDTMF: function(tones, duration, interToneGap) {
    this._sender._pc._checkClosed();

    if (this._sender._pc._senders.indexOf(this._sender.__DOM_IMPL__) == -1) {
      throw new this._sender._pc._win.DOMException("RTCRtpSender is stopped",
                                                   "InvalidStateError");
    }

    duration = Math.max(40, Math.min(duration, 6000));
    if (interToneGap < 30) interToneGap = 30;

    tones = tones.toUpperCase();

    if (tones.match(/[^0-9A-D#*,]/)) {
      throw new this._sender._pc._win.DOMException("Invalid DTMF characters",
                                                   "InvalidCharacterError");
    }

    this._sender._pc._insertDTMF(this._sender, tones, duration, interToneGap);
  },
};

function RTCRtpSender(pc, track, stream) {
  this._pc = pc;
  this.track = track;
  this._stream = stream;
  this.dtmf = pc._win.RTCDTMFSender._create(pc._win, new RTCDTMFSender(this));
}
RTCRtpSender.prototype = {
  classDescription: "RTCRtpSender",
  classID: PC_SENDER_CID,
  contractID: PC_SENDER_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),

  replaceTrack: function(withTrack) {
    return this._pc._chain(() => this._pc._replaceTrack(this, withTrack));
  },

  setParameters: function(parameters) {
    return this._pc._win.Promise.resolve()
      .then(() => this._pc._setParameters(this, parameters));
  },

  getParameters: function() {
    return this._pc._getParameters(this);
  }
};

function RTCRtpReceiver(pc, track) {
  this._pc = pc;
  this.track = track;
}
RTCRtpReceiver.prototype = {
  classDescription: "RTCRtpReceiver",
  classID: PC_RECEIVER_CID,
  contractID: PC_RECEIVER_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),
};

function CreateOfferRequest(windowID, innerWindowID, callID, isSecure) {
  this.windowID = windowID;
  this.innerWindowID = innerWindowID;
  this.callID = callID;
  this.isSecure = isSecure;
}
CreateOfferRequest.prototype = {
  classDescription: "CreateOfferRequest",
  classID: PC_COREQUEST_CID,
  contractID: PC_COREQUEST_CONTRACT,
  QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports]),
};

this.NSGetFactory = XPCOMUtils.generateNSGetFactory(
  [GlobalPCList,
   RTCDTMFSender,
   RTCIceCandidate,
   RTCSessionDescription,
   RTCPeerConnection,
   RTCPeerConnectionStatic,
   RTCRtpReceiver,
   RTCRtpSender,
   RTCStatsReport,
   PeerConnectionObserver,
   CreateOfferRequest]
);