Add m-esr52 at 52.6.0

3 files changed, 3515 insertions, 0 deletions

diff --git a/devtools/shared/client/connection-manager.js b/devtools/shared/client/connection-manager.js
new file mode 100644
index 000000000..ef242db85
--- /dev/null
+++ b/devtools/shared/client/connection-manager.js
@@ -0,0 +1,382 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* 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 {Cc, Ci, Cu, Cr} = require("chrome");
+const EventEmitter = require("devtools/shared/event-emitter");
+const DevToolsUtils = require("devtools/shared/DevToolsUtils");
+const { DebuggerServer } = require("devtools/server/main");
+const { DebuggerClient } = require("devtools/shared/client/main");
+const Services = require("Services");
+const { Task } = require("devtools/shared/task");
+
+const REMOTE_TIMEOUT = "devtools.debugger.remote-timeout";
+
+/**
+ * Connection Manager.
+ *
+ * To use this module:
+ * const {ConnectionManager} = require("devtools/shared/client/connection-manager");
+ *
+ * # ConnectionManager
+ *
+ * Methods:
+ *  . Connection createConnection(host, port)
+ *  . void       destroyConnection(connection)
+ *  . Number     getFreeTCPPort()
+ *
+ * Properties:
+ *  . Array      connections
+ *
+ * # Connection
+ *
+ * A connection is a wrapper around a debugger client. It has a simple
+ * API to instantiate a connection to a debugger server. Once disconnected,
+ * no need to re-create a Connection object. Calling `connect()` again
+ * will re-create a debugger client.
+ *
+ * Methods:
+ *  . connect()             Connect to host:port. Expect a "connecting" event.
+ *                          If no host is not specified, a local pipe is used
+ *  . connect(transport)    Connect via transport. Expect a "connecting" event.
+ *  . disconnect()          Disconnect if connected. Expect a "disconnecting" event
+ *
+ * Properties:
+ *  . host                  IP address or hostname
+ *  . port                  Port
+ *  . logs                  Current logs. "newlog" event notifies new available logs
+ *  . store                 Reference to a local data store (see below)
+ *  . keepConnecting        Should the connection keep trying to connect?
+ *  . timeoutDelay          When should we give up (in ms)?
+ *                          0 means wait forever.
+ *  . encryption            Should the connection be encrypted?
+ *  . authentication        What authentication scheme should be used?
+ *  . authenticator         The |Authenticator| instance used.  Overriding
+ *                          properties of this instance may be useful to
+ *                          customize authentication UX for a specific use case.
+ *  . advertisement         The server's advertisement if found by discovery
+ *  . status                Connection status:
+ *                            Connection.Status.CONNECTED
+ *                            Connection.Status.DISCONNECTED
+ *                            Connection.Status.CONNECTING
+ *                            Connection.Status.DISCONNECTING
+ *                            Connection.Status.DESTROYED
+ *
+ * Events (as in event-emitter.js):
+ *  . Connection.Events.CONNECTING      Trying to connect to host:port
+ *  . Connection.Events.CONNECTED       Connection is successful
+ *  . Connection.Events.DISCONNECTING   Trying to disconnect from server
+ *  . Connection.Events.DISCONNECTED    Disconnected (at client request, or because of a timeout or connection error)
+ *  . Connection.Events.STATUS_CHANGED  The connection status (connection.status) has changed
+ *  . Connection.Events.TIMEOUT         Connection timeout
+ *  . Connection.Events.HOST_CHANGED    Host has changed
+ *  . Connection.Events.PORT_CHANGED    Port has changed
+ *  . Connection.Events.NEW_LOG         A new log line is available
+ *
+ */
+
+var ConnectionManager = {
+  _connections: new Set(),
+  createConnection: function (host, port) {
+    let c = new Connection(host, port);
+    c.once("destroy", (event) => this.destroyConnection(c));
+    this._connections.add(c);
+    this.emit("new", c);
+    return c;
+  },
+  destroyConnection: function (connection) {
+    if (this._connections.has(connection)) {
+      this._connections.delete(connection);
+      if (connection.status != Connection.Status.DESTROYED) {
+        connection.destroy();
+      }
+    }
+  },
+  get connections() {
+    return [...this._connections];
+  },
+  getFreeTCPPort: function () {
+    let serv = Cc["@mozilla.org/network/server-socket;1"]
+                 .createInstance(Ci.nsIServerSocket);
+    serv.init(-1, true, -1);
+    let port = serv.port;
+    serv.close();
+    return port;
+  },
+};
+
+EventEmitter.decorate(ConnectionManager);
+
+var lastID = -1;
+
+function Connection(host, port) {
+  EventEmitter.decorate(this);
+  this.uid = ++lastID;
+  this.host = host;
+  this.port = port;
+  this._setStatus(Connection.Status.DISCONNECTED);
+  this._onDisconnected = this._onDisconnected.bind(this);
+  this._onConnected = this._onConnected.bind(this);
+  this._onTimeout = this._onTimeout.bind(this);
+  this.resetOptions();
+}
+
+Connection.Status = {
+  CONNECTED: "connected",
+  DISCONNECTED: "disconnected",
+  CONNECTING: "connecting",
+  DISCONNECTING: "disconnecting",
+  DESTROYED: "destroyed",
+};
+
+Connection.Events = {
+  CONNECTED: Connection.Status.CONNECTED,
+  DISCONNECTED: Connection.Status.DISCONNECTED,
+  CONNECTING: Connection.Status.CONNECTING,
+  DISCONNECTING: Connection.Status.DISCONNECTING,
+  DESTROYED: Connection.Status.DESTROYED,
+  TIMEOUT: "timeout",
+  STATUS_CHANGED: "status-changed",
+  HOST_CHANGED: "host-changed",
+  PORT_CHANGED: "port-changed",
+  NEW_LOG: "new_log"
+};
+
+Connection.prototype = {
+  logs: "",
+  log: function (str) {
+    let d = new Date();
+    let hours = ("0" + d.getHours()).slice(-2);
+    let minutes = ("0" + d.getMinutes()).slice(-2);
+    let seconds = ("0" + d.getSeconds()).slice(-2);
+    let timestamp = [hours, minutes, seconds].join(":") + ": ";
+    str = timestamp + str;
+    this.logs += "\n" + str;
+    this.emit(Connection.Events.NEW_LOG, str);
+  },
+
+  get client() {
+    return this._client;
+  },
+
+  get host() {
+    return this._host;
+  },
+
+  set host(value) {
+    if (this._host && this._host == value)
+      return;
+    this._host = value;
+    this.emit(Connection.Events.HOST_CHANGED);
+  },
+
+  get port() {
+    return this._port;
+  },
+
+  set port(value) {
+    if (this._port && this._port == value)
+      return;
+    this._port = value;
+    this.emit(Connection.Events.PORT_CHANGED);
+  },
+
+  get authentication() {
+    return this._authentication;
+  },
+
+  set authentication(value) {
+    this._authentication = value;
+    // Create an |Authenticator| of this type
+    if (!value) {
+      this.authenticator = null;
+      return;
+    }
+    let AuthenticatorType = DebuggerClient.Authenticators.get(value);
+    this.authenticator = new AuthenticatorType.Client();
+  },
+
+  get advertisement() {
+    return this._advertisement;
+  },
+
+  set advertisement(advertisement) {
+    // The full advertisement may contain more info than just the standard keys
+    // below, so keep a copy for use during connection later.
+    this._advertisement = advertisement;
+    if (advertisement) {
+      ["host", "port", "encryption", "authentication"].forEach(key => {
+        this[key] = advertisement[key];
+      });
+    }
+  },
+
+  /**
+   * Settings to be passed to |socketConnect| at connection time.
+   */
+  get socketSettings() {
+    let settings = {};
+    if (this.advertisement) {
+      // Use the advertisement as starting point if it exists, as it may contain
+      // extra data, like the server's cert.
+      Object.assign(settings, this.advertisement);
+    }
+    Object.assign(settings, {
+      host: this.host,
+      port: this.port,
+      encryption: this.encryption,
+      authenticator: this.authenticator
+    });
+    return settings;
+  },
+
+  timeoutDelay: Services.prefs.getIntPref(REMOTE_TIMEOUT),
+
+  resetOptions() {
+    this.keepConnecting = false;
+    this.timeoutDelay = Services.prefs.getIntPref(REMOTE_TIMEOUT);
+    this.encryption = false;
+    this.authentication = null;
+    this.advertisement = null;
+  },
+
+  disconnect: function (force) {
+    if (this.status == Connection.Status.DESTROYED) {
+      return;
+    }
+    clearTimeout(this._timeoutID);
+    if (this.status == Connection.Status.CONNECTED ||
+        this.status == Connection.Status.CONNECTING) {
+      this.log("disconnecting");
+      this._setStatus(Connection.Status.DISCONNECTING);
+      if (this._client) {
+        this._client.close();
+      }
+    }
+  },
+
+  connect: function (transport) {
+    if (this.status == Connection.Status.DESTROYED) {
+      return;
+    }
+    if (!this._client) {
+      this._customTransport = transport;
+      if (this._customTransport) {
+        this.log("connecting (custom transport)");
+      } else {
+        this.log("connecting to " + this.host + ":" + this.port);
+      }
+      this._setStatus(Connection.Status.CONNECTING);
+
+      if (this.timeoutDelay > 0) {
+        this._timeoutID = setTimeout(this._onTimeout, this.timeoutDelay);
+      }
+      this._clientConnect();
+    } else {
+      let msg = "Can't connect. Client is not fully disconnected";
+      this.log(msg);
+      throw new Error(msg);
+    }
+  },
+
+  destroy: function () {
+    this.log("killing connection");
+    clearTimeout(this._timeoutID);
+    this.keepConnecting = false;
+    if (this._client) {
+      this._client.close();
+      this._client = null;
+    }
+    this._setStatus(Connection.Status.DESTROYED);
+  },
+
+  _getTransport: Task.async(function* () {
+    if (this._customTransport) {
+      return this._customTransport;
+    }
+    if (!this.host) {
+      return DebuggerServer.connectPipe();
+    }
+    let settings = this.socketSettings;
+    let transport = yield DebuggerClient.socketConnect(settings);
+    return transport;
+  }),
+
+  _clientConnect: function () {
+    this._getTransport().then(transport => {
+      if (!transport) {
+        return;
+      }
+      this._client = new DebuggerClient(transport);
+      this._client.addOneTimeListener("closed", this._onDisconnected);
+      this._client.connect().then(this._onConnected);
+    }, e => {
+      // If we're continuously trying to connect, we expect the connection to be
+      // rejected a couple times, so don't log these.
+      if (!this.keepConnecting || e.result !== Cr.NS_ERROR_CONNECTION_REFUSED) {
+        console.error(e);
+      }
+      // In some cases, especially on Mac, the openOutputStream call in
+      // DebuggerClient.socketConnect may throw NS_ERROR_NOT_INITIALIZED.
+      // It occurs when we connect agressively to the simulator,
+      // and keep trying to open a socket to the server being started in
+      // the simulator.
+      this._onDisconnected();
+    });
+  },
+
+  get status() {
+    return this._status;
+  },
+
+  _setStatus: function (value) {
+    if (this._status && this._status == value)
+      return;
+    this._status = value;
+    this.emit(value);
+    this.emit(Connection.Events.STATUS_CHANGED, value);
+  },
+
+  _onDisconnected: function () {
+    this._client = null;
+    this._customTransport = null;
+
+    if (this._status == Connection.Status.CONNECTING && this.keepConnecting) {
+      setTimeout(() => this._clientConnect(), 100);
+      return;
+    }
+
+    clearTimeout(this._timeoutID);
+
+    switch (this.status) {
+      case Connection.Status.CONNECTED:
+        this.log("disconnected (unexpected)");
+        break;
+      case Connection.Status.CONNECTING:
+        this.log("connection error. Possible causes: USB port not connected, port not forwarded (adb forward), wrong host or port, remote debugging not enabled on the device.");
+        break;
+      default:
+        this.log("disconnected");
+    }
+    this._setStatus(Connection.Status.DISCONNECTED);
+  },
+
+  _onConnected: function () {
+    this.log("connected");
+    clearTimeout(this._timeoutID);
+    this._setStatus(Connection.Status.CONNECTED);
+  },
+
+  _onTimeout: function () {
+    this.log("connection timeout. Possible causes: didn't click on 'accept' (prompt).");
+    this.emit(Connection.Events.TIMEOUT);
+    this.disconnect();
+  },
+};
+
+exports.ConnectionManager = ConnectionManager;
+exports.Connection = Connection;
diff --git a/devtools/shared/client/main.js b/devtools/shared/client/main.js
new file mode 100644
index 000000000..0db8e16c2
--- /dev/null
+++ b/devtools/shared/client/main.js
@@ -0,0 +1,3123 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* 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 { Ci, Cu } = require("chrome");
+const Services = require("Services");
+const DevToolsUtils = require("devtools/shared/DevToolsUtils");
+const { getStack, callFunctionWithAsyncStack } = require("devtools/shared/platform/stack");
+
+const promise = Cu.import("resource://devtools/shared/deprecated-sync-thenables.js", {}).Promise;
+
+loader.lazyRequireGetter(this, "events", "sdk/event/core");
+loader.lazyRequireGetter(this, "WebConsoleClient", "devtools/shared/webconsole/client", true);
+loader.lazyRequireGetter(this, "DebuggerSocket", "devtools/shared/security/socket", true);
+loader.lazyRequireGetter(this, "Authentication", "devtools/shared/security/auth");
+
+const noop = () => {};
+
+/**
+ * TODO: Get rid of this API in favor of EventTarget (bug 1042642)
+ *
+ * Add simple event notification to a prototype object. Any object that has
+ * some use for event notifications or the observer pattern in general can be
+ * augmented with the necessary facilities by passing its prototype to this
+ * function.
+ *
+ * @param aProto object
+ *        The prototype object that will be modified.
+ */
+function eventSource(aProto) {
+  /**
+   * Add a listener to the event source for a given event.
+   *
+   * @param aName string
+   *        The event to listen for.
+   * @param aListener function
+   *        Called when the event is fired. If the same listener
+   *        is added more than once, it will be called once per
+   *        addListener call.
+   */
+  aProto.addListener = function (aName, aListener) {
+    if (typeof aListener != "function") {
+      throw TypeError("Listeners must be functions.");
+    }
+
+    if (!this._listeners) {
+      this._listeners = {};
+    }
+
+    this._getListeners(aName).push(aListener);
+  };
+
+  /**
+   * Add a listener to the event source for a given event. The
+   * listener will be removed after it is called for the first time.
+   *
+   * @param aName string
+   *        The event to listen for.
+   * @param aListener function
+   *        Called when the event is fired.
+   */
+  aProto.addOneTimeListener = function (aName, aListener) {
+    let l = (...args) => {
+      this.removeListener(aName, l);
+      aListener.apply(null, args);
+    };
+    this.addListener(aName, l);
+  };
+
+  /**
+   * Remove a listener from the event source previously added with
+   * addListener().
+   *
+   * @param aName string
+   *        The event name used during addListener to add the listener.
+   * @param aListener function
+   *        The callback to remove. If addListener was called multiple
+   *        times, all instances will be removed.
+   */
+  aProto.removeListener = function (aName, aListener) {
+    if (!this._listeners || (aListener && !this._listeners[aName])) {
+      return;
+    }
+
+    if (!aListener) {
+      this._listeners[aName] = [];
+    }
+    else {
+      this._listeners[aName] =
+        this._listeners[aName].filter(function (l) { return l != aListener; });
+    }
+  };
+
+  /**
+   * Returns the listeners for the specified event name. If none are defined it
+   * initializes an empty list and returns that.
+   *
+   * @param aName string
+   *        The event name.
+   */
+  aProto._getListeners = function (aName) {
+    if (aName in this._listeners) {
+      return this._listeners[aName];
+    }
+    this._listeners[aName] = [];
+    return this._listeners[aName];
+  };
+
+  /**
+   * Notify listeners of an event.
+   *
+   * @param aName string
+   *        The event to fire.
+   * @param arguments
+   *        All arguments will be passed along to the listeners,
+   *        including the name argument.
+   */
+  aProto.emit = function () {
+    if (!this._listeners) {
+      return;
+    }
+
+    let name = arguments[0];
+    let listeners = this._getListeners(name).slice(0);
+
+    for (let listener of listeners) {
+      try {
+        listener.apply(null, arguments);
+      } catch (e) {
+        // Prevent a bad listener from interfering with the others.
+        DevToolsUtils.reportException("notify event '" + name + "'", e);
+      }
+    }
+  };
+}
+
+/**
+ * Set of protocol messages that affect thread state, and the
+ * state the actor is in after each message.
+ */
+const ThreadStateTypes = {
+  "paused": "paused",
+  "resumed": "attached",
+  "detached": "detached",
+  "running": "attached"
+};
+
+/**
+ * Set of protocol messages that are sent by the server without a prior request
+ * by the client.
+ */
+const UnsolicitedNotifications = {
+  "consoleAPICall": "consoleAPICall",
+  "eventNotification": "eventNotification",
+  "fileActivity": "fileActivity",
+  "lastPrivateContextExited": "lastPrivateContextExited",
+  "logMessage": "logMessage",
+  "networkEvent": "networkEvent",
+  "networkEventUpdate": "networkEventUpdate",
+  "newGlobal": "newGlobal",
+  "newScript": "newScript",
+  "tabDetached": "tabDetached",
+  "tabListChanged": "tabListChanged",
+  "reflowActivity": "reflowActivity",
+  "addonListChanged": "addonListChanged",
+  "workerListChanged": "workerListChanged",
+  "serviceWorkerRegistrationListChanged": "serviceWorkerRegistrationList",
+  "tabNavigated": "tabNavigated",
+  "frameUpdate": "frameUpdate",
+  "pageError": "pageError",
+  "documentLoad": "documentLoad",
+  "enteredFrame": "enteredFrame",
+  "exitedFrame": "exitedFrame",
+  "appOpen": "appOpen",
+  "appClose": "appClose",
+  "appInstall": "appInstall",
+  "appUninstall": "appUninstall",
+  "evaluationResult": "evaluationResult",
+  "newSource": "newSource",
+  "updatedSource": "updatedSource",
+};
+
+/**
+ * Set of pause types that are sent by the server and not as an immediate
+ * response to a client request.
+ */
+const UnsolicitedPauses = {
+  "resumeLimit": "resumeLimit",
+  "debuggerStatement": "debuggerStatement",
+  "breakpoint": "breakpoint",
+  "DOMEvent": "DOMEvent",
+  "watchpoint": "watchpoint",
+  "exception": "exception"
+};
+
+/**
+ * Creates a client for the remote debugging protocol server. This client
+ * provides the means to communicate with the server and exchange the messages
+ * required by the protocol in a traditional JavaScript API.
+ */
+const DebuggerClient = exports.DebuggerClient = function (aTransport)
+{
+  this._transport = aTransport;
+  this._transport.hooks = this;
+
+  // Map actor ID to client instance for each actor type.
+  this._clients = new Map();
+
+  this._pendingRequests = new Map();
+  this._activeRequests = new Map();
+  this._eventsEnabled = true;
+
+  this.traits = {};
+
+  this.request = this.request.bind(this);
+  this.localTransport = this._transport.onOutputStreamReady === undefined;
+
+  /*
+   * As the first thing on the connection, expect a greeting packet from
+   * the connection's root actor.
+   */
+  this.mainRoot = null;
+  this.expectReply("root", (aPacket) => {
+    this.mainRoot = new RootClient(this, aPacket);
+    this.emit("connected", aPacket.applicationType, aPacket.traits);
+  });
+};
+
+/**
+ * A declarative helper for defining methods that send requests to the server.
+ *
+ * @param aPacketSkeleton
+ *        The form of the packet to send. Can specify fields to be filled from
+ *        the parameters by using the |args| function.
+ * @param before
+ *        The function to call before sending the packet. Is passed the packet,
+ *        and the return value is used as the new packet. The |this| context is
+ *        the instance of the client object we are defining a method for.
+ * @param after
+ *        The function to call after the response is received. It is passed the
+ *        response, and the return value is considered the new response that
+ *        will be passed to the callback. The |this| context is the instance of
+ *        the client object we are defining a method for.
+ * @return Request
+ *         The `Request` object that is a Promise object and resolves once
+ *         we receive the response. (See request method for more details)
+ */
+DebuggerClient.requester = function (aPacketSkeleton, config = {}) {
+  let { before, after } = config;
+  return DevToolsUtils.makeInfallible(function (...args) {
+    let outgoingPacket = {
+      to: aPacketSkeleton.to || this.actor
+    };
+
+    let maxPosition = -1;
+    for (let k of Object.keys(aPacketSkeleton)) {
+      if (aPacketSkeleton[k] instanceof DebuggerClient.Argument) {
+        let { position } = aPacketSkeleton[k];
+        outgoingPacket[k] = aPacketSkeleton[k].getArgument(args);
+        maxPosition = Math.max(position, maxPosition);
+      } else {
+        outgoingPacket[k] = aPacketSkeleton[k];
+      }
+    }
+
+    if (before) {
+      outgoingPacket = before.call(this, outgoingPacket);
+    }
+
+    return this.request(outgoingPacket, DevToolsUtils.makeInfallible((aResponse) => {
+      if (after) {
+        let { from } = aResponse;
+        aResponse = after.call(this, aResponse);
+        if (!aResponse.from) {
+          aResponse.from = from;
+        }
+      }
+
+      // The callback is always the last parameter.
+      let thisCallback = args[maxPosition + 1];
+      if (thisCallback) {
+        thisCallback(aResponse);
+      }
+    }, "DebuggerClient.requester request callback"));
+  }, "DebuggerClient.requester");
+};
+
+function args(aPos) {
+  return new DebuggerClient.Argument(aPos);
+}
+
+DebuggerClient.Argument = function (aPosition) {
+  this.position = aPosition;
+};
+
+DebuggerClient.Argument.prototype.getArgument = function (aParams) {
+  if (!(this.position in aParams)) {
+    throw new Error("Bad index into params: " + this.position);
+  }
+  return aParams[this.position];
+};
+
+// Expose these to save callers the trouble of importing DebuggerSocket
+DebuggerClient.socketConnect = function (options) {
+  // Defined here instead of just copying the function to allow lazy-load
+  return DebuggerSocket.connect(options);
+};
+DevToolsUtils.defineLazyGetter(DebuggerClient, "Authenticators", () => {
+  return Authentication.Authenticators;
+});
+DevToolsUtils.defineLazyGetter(DebuggerClient, "AuthenticationResult", () => {
+  return Authentication.AuthenticationResult;
+});
+
+DebuggerClient.prototype = {
+  /**
+   * Connect to the server and start exchanging protocol messages.
+   *
+   * @param aOnConnected function
+   *        If specified, will be called when the greeting packet is
+   *        received from the debugging server.
+   *
+   * @return Promise
+   *         Resolves once connected with an array whose first element
+   *         is the application type, by default "browser", and the second
+   *         element is the traits object (help figure out the features
+   *         and behaviors of the server we connect to. See RootActor).
+   */
+  connect: function (aOnConnected) {
+    let deferred = promise.defer();
+    this.emit("connect");
+
+    // Also emit the event on the |DebuggerClient| object (not on the instance),
+    // so it's possible to track all instances.
+    events.emit(DebuggerClient, "connect", this);
+
+    this.addOneTimeListener("connected", (aName, aApplicationType, aTraits) => {
+      this.traits = aTraits;
+      if (aOnConnected) {
+        aOnConnected(aApplicationType, aTraits);
+      }
+      deferred.resolve([aApplicationType, aTraits]);
+    });
+
+    this._transport.ready();
+    return deferred.promise;
+  },
+
+  /**
+   * Shut down communication with the debugging server.
+   *
+   * @param aOnClosed function
+   *        If specified, will be called when the debugging connection
+   *        has been closed. This parameter is deprecated - please use
+   *        the returned Promise.
+   * @return Promise
+   *         Resolves after the underlying transport is closed.
+   */
+  close: function (aOnClosed) {
+    let deferred = promise.defer();
+    if (aOnClosed) {
+      deferred.promise.then(aOnClosed);
+    }
+
+    // Disable detach event notifications, because event handlers will be in a
+    // cleared scope by the time they run.
+    this._eventsEnabled = false;
+
+    let cleanup = () => {
+      this._transport.close();
+      this._transport = null;
+    };
+
+    // If the connection is already closed,
+    // there is no need to detach client
+    // as we won't be able to send any message.
+    if (this._closed) {
+      cleanup();
+      deferred.resolve();
+      return deferred.promise;
+    }
+
+    this.addOneTimeListener("closed", deferred.resolve);
+
+    // Call each client's `detach` method by calling
+    // lastly registered ones first to give a chance
+    // to detach child clients first.
+    let clients = [...this._clients.values()];
+    this._clients.clear();
+    const detachClients = () => {
+      let client = clients.pop();
+      if (!client) {
+        // All clients detached.
+        cleanup();
+        return;
+      }
+      if (client.detach) {
+        client.detach(detachClients);
+        return;
+      }
+      detachClients();
+    };
+    detachClients();
+
+    return deferred.promise;
+  },
+
+  /*
+   * This function exists only to preserve DebuggerClient's interface;
+   * new code should say 'client.mainRoot.listTabs()'.
+   */
+  listTabs: function (aOnResponse) { return this.mainRoot.listTabs(aOnResponse); },
+
+  /*
+   * This function exists only to preserve DebuggerClient's interface;
+   * new code should say 'client.mainRoot.listAddons()'.
+   */
+  listAddons: function (aOnResponse) { return this.mainRoot.listAddons(aOnResponse); },
+
+  getTab: function (aFilter) { return this.mainRoot.getTab(aFilter); },
+
+  /**
+   * Attach to a tab actor.
+   *
+   * @param string aTabActor
+   *        The actor ID for the tab to attach.
+   * @param function aOnResponse
+   *        Called with the response packet and a TabClient
+   *        (which will be undefined on error).
+   */
+  attachTab: function (aTabActor, aOnResponse = noop) {
+    if (this._clients.has(aTabActor)) {
+      let cachedTab = this._clients.get(aTabActor);
+      let cachedResponse = {
+        cacheDisabled: cachedTab.cacheDisabled,
+        javascriptEnabled: cachedTab.javascriptEnabled,
+        traits: cachedTab.traits,
+      };
+      DevToolsUtils.executeSoon(() => aOnResponse(cachedResponse, cachedTab));
+      return promise.resolve([cachedResponse, cachedTab]);
+    }
+
+    let packet = {
+      to: aTabActor,
+      type: "attach"
+    };
+    return this.request(packet).then(aResponse => {
+      let tabClient;
+      if (!aResponse.error) {
+        tabClient = new TabClient(this, aResponse);
+        this.registerClient(tabClient);
+      }
+      aOnResponse(aResponse, tabClient);
+      return [aResponse, tabClient];
+    });
+  },
+
+  attachWorker: function DC_attachWorker(aWorkerActor, aOnResponse = noop) {
+    let workerClient = this._clients.get(aWorkerActor);
+    if (workerClient !== undefined) {
+      let response = {
+        from: workerClient.actor,
+        type: "attached",
+        url: workerClient.url
+      };
+      DevToolsUtils.executeSoon(() => aOnResponse(response, workerClient));
+      return promise.resolve([response, workerClient]);
+    }
+
+    return this.request({ to: aWorkerActor, type: "attach" }).then(aResponse => {
+      if (aResponse.error) {
+        aOnResponse(aResponse, null);
+        return [aResponse, null];
+      }
+
+      let workerClient = new WorkerClient(this, aResponse);
+      this.registerClient(workerClient);
+      aOnResponse(aResponse, workerClient);
+      return [aResponse, workerClient];
+    });
+  },
+
+  /**
+   * Attach to an addon actor.
+   *
+   * @param string aAddonActor
+   *        The actor ID for the addon to attach.
+   * @param function aOnResponse
+   *        Called with the response packet and a AddonClient
+   *        (which will be undefined on error).
+   */
+  attachAddon: function DC_attachAddon(aAddonActor, aOnResponse = noop) {
+    let packet = {
+      to: aAddonActor,
+      type: "attach"
+    };
+    return this.request(packet).then(aResponse => {
+      let addonClient;
+      if (!aResponse.error) {
+        addonClient = new AddonClient(this, aAddonActor);
+        this.registerClient(addonClient);
+        this.activeAddon = addonClient;
+      }
+      aOnResponse(aResponse, addonClient);
+      return [aResponse, addonClient];
+    });
+  },
+
+  /**
+   * Attach to a Web Console actor.
+   *
+   * @param string aConsoleActor
+   *        The ID for the console actor to attach to.
+   * @param array aListeners
+   *        The console listeners you want to start.
+   * @param function aOnResponse
+   *        Called with the response packet and a WebConsoleClient
+   *        instance (which will be undefined on error).
+   */
+  attachConsole:
+  function (aConsoleActor, aListeners, aOnResponse = noop) {
+    let packet = {
+      to: aConsoleActor,
+      type: "startListeners",
+      listeners: aListeners,
+    };
+
+    return this.request(packet).then(aResponse => {
+      let consoleClient;
+      if (!aResponse.error) {
+        if (this._clients.has(aConsoleActor)) {
+          consoleClient = this._clients.get(aConsoleActor);
+        } else {
+          consoleClient = new WebConsoleClient(this, aResponse);
+          this.registerClient(consoleClient);
+        }
+      }
+      aOnResponse(aResponse, consoleClient);
+      return [aResponse, consoleClient];
+    });
+  },
+
+  /**
+   * Attach to a global-scoped thread actor for chrome debugging.
+   *
+   * @param string aThreadActor
+   *        The actor ID for the thread to attach.
+   * @param function aOnResponse
+   *        Called with the response packet and a ThreadClient
+   *        (which will be undefined on error).
+   * @param object aOptions
+   *        Configuration options.
+   *        - useSourceMaps: whether to use source maps or not.
+   */
+  attachThread: function (aThreadActor, aOnResponse = noop, aOptions = {}) {
+    if (this._clients.has(aThreadActor)) {
+      let client = this._clients.get(aThreadActor);
+      DevToolsUtils.executeSoon(() => aOnResponse({}, client));
+      return promise.resolve([{}, client]);
+    }
+
+    let packet = {
+      to: aThreadActor,
+      type: "attach",
+      options: aOptions
+    };
+    return this.request(packet).then(aResponse => {
+      if (!aResponse.error) {
+        var threadClient = new ThreadClient(this, aThreadActor);
+        this.registerClient(threadClient);
+      }
+      aOnResponse(aResponse, threadClient);
+      return [aResponse, threadClient];
+    });
+  },
+
+  /**
+   * Attach to a trace actor.
+   *
+   * @param string aTraceActor
+   *        The actor ID for the tracer to attach.
+   * @param function aOnResponse
+   *        Called with the response packet and a TraceClient
+   *        (which will be undefined on error).
+   */
+  attachTracer: function (aTraceActor, aOnResponse = noop) {
+    if (this._clients.has(aTraceActor)) {
+      let client = this._clients.get(aTraceActor);
+      DevToolsUtils.executeSoon(() => aOnResponse({}, client));
+      return promise.resolve([{}, client]);
+    }
+
+    let packet = {
+      to: aTraceActor,
+      type: "attach"
+    };
+    return this.request(packet).then(aResponse => {
+      if (!aResponse.error) {
+        var traceClient = new TraceClient(this, aTraceActor);
+        this.registerClient(traceClient);
+      }
+      aOnResponse(aResponse, traceClient);
+      return [aResponse, traceClient];
+    });
+  },
+
+  /**
+   * Fetch the ChromeActor for the main process or ChildProcessActor for a
+   * a given child process ID.
+   *
+   * @param number aId
+   *        The ID for the process to attach (returned by `listProcesses`).
+   *        Connected to the main process if omitted, or is 0.
+   */
+  getProcess: function (aId) {
+    let packet = {
+      to: "root",
+      type: "getProcess"
+    };
+    if (typeof (aId) == "number") {
+      packet.id = aId;
+    }
+    return this.request(packet);
+  },
+
+  /**
+   * Release an object actor.
+   *
+   * @param string aActor
+   *        The actor ID to send the request to.
+   * @param aOnResponse function
+   *        If specified, will be called with the response packet when
+   *        debugging server responds.
+   */
+  release: DebuggerClient.requester({
+    to: args(0),
+    type: "release"
+  }),
+
+  /**
+   * Send a request to the debugging server.
+   *
+   * @param aRequest object
+   *        A JSON packet to send to the debugging server.
+   * @param aOnResponse function
+   *        If specified, will be called with the JSON response packet when
+   *        debugging server responds.
+   * @return Request
+   *         This object emits a number of events to allow you to respond to
+   *         different parts of the request lifecycle.
+   *         It is also a Promise object, with a `then` method, that is resolved
+   *         whenever a JSON or a Bulk response is received; and is rejected
+   *         if the response is an error.
+   *         Note: This return value can be ignored if you are using JSON alone,
+   *         because the callback provided in |aOnResponse| will be bound to the
+   *         "json-reply" event automatically.
+   *
+   *         Events emitted:
+   *         * json-reply: The server replied with a JSON packet, which is
+   *           passed as event data.
+   *         * bulk-reply: The server replied with bulk data, which you can read
+   *           using the event data object containing:
+   *           * actor:  Name of actor that received the packet
+   *           * type:   Name of actor's method that was called on receipt
+   *           * length: Size of the data to be read
+   *           * stream: This input stream should only be used directly if you
+   *                     can ensure that you will read exactly |length| bytes
+   *                     and will not close the stream when reading is complete
+   *           * done:   If you use the stream directly (instead of |copyTo|
+   *                     below), you must signal completion by resolving /
+   *                     rejecting this deferred.  If it's rejected, the
+   *                     transport will be closed.  If an Error is supplied as a
+   *                     rejection value, it will be logged via |dumpn|.  If you
+   *                     do use |copyTo|, resolving is taken care of for you
+   *                     when copying completes.
+   *           * copyTo: A helper function for getting your data out of the
+   *                     stream that meets the stream handling requirements
+   *                     above, and has the following signature:
+   *             @param  output nsIAsyncOutputStream
+   *                     The stream to copy to.
+   *             @return Promise
+   *                     The promise is resolved when copying completes or
+   *                     rejected if any (unexpected) errors occur.
+   *                     This object also emits "progress" events for each chunk
+   *                     that is copied.  See stream-utils.js.
+   */
+  request: function (aRequest, aOnResponse) {
+    if (!this.mainRoot) {
+      throw Error("Have not yet received a hello packet from the server.");
+    }
+    let type = aRequest.type || "";
+    if (!aRequest.to) {
+      throw Error("'" + type + "' request packet has no destination.");
+    }
+    if (this._closed) {
+      let msg = "'" + type + "' request packet to " +
+                "'" + aRequest.to + "' " +
+               "can't be sent as the connection is closed.";
+      let resp = { error: "connectionClosed", message: msg };
+      if (aOnResponse) {
+        aOnResponse(resp);
+      }
+      return promise.reject(resp);
+    }
+
+    let request = new Request(aRequest);
+    request.format = "json";
+    request.stack = getStack();
+    if (aOnResponse) {
+      request.on("json-reply", aOnResponse);
+    }
+
+    this._sendOrQueueRequest(request);
+
+    // Implement a Promise like API on the returned object
+    // that resolves/rejects on request response
+    let deferred = promise.defer();
+    function listenerJson(resp) {
+      request.off("json-reply", listenerJson);
+      request.off("bulk-reply", listenerBulk);
+      if (resp.error) {
+        deferred.reject(resp);
+      } else {
+        deferred.resolve(resp);
+      }
+    }
+    function listenerBulk(resp) {
+      request.off("json-reply", listenerJson);
+      request.off("bulk-reply", listenerBulk);
+      deferred.resolve(resp);
+    }
+    request.on("json-reply", listenerJson);
+    request.on("bulk-reply", listenerBulk);
+    request.then = deferred.promise.then.bind(deferred.promise);
+
+    return request;
+  },
+
+  /**
+   * Transmit streaming data via a bulk request.
+   *
+   * This method initiates the bulk send process by queuing up the header data.
+   * The caller receives eventual access to a stream for writing.
+   *
+   * Since this opens up more options for how the server might respond (it could
+   * send back either JSON or bulk data), and the returned Request object emits
+   * events for different stages of the request process that you may want to
+   * react to.
+   *
+   * @param request Object
+   *        This is modeled after the format of JSON packets above, but does not
+   *        actually contain the data, but is instead just a routing header:
+   *          * actor:  Name of actor that will receive the packet
+   *          * type:   Name of actor's method that should be called on receipt
+   *          * length: Size of the data to be sent
+   * @return Request
+   *         This object emits a number of events to allow you to respond to
+   *         different parts of the request lifecycle.
+   *
+   *         Events emitted:
+   *         * bulk-send-ready: Ready to send bulk data to the server, using the
+   *           event data object containing:
+   *           * stream:   This output stream should only be used directly if
+   *                       you can ensure that you will write exactly |length|
+   *                       bytes and will not close the stream when writing is
+   *                       complete
+   *           * done:     If you use the stream directly (instead of |copyFrom|
+   *                       below), you must signal completion by resolving /
+   *                       rejecting this deferred.  If it's rejected, the
+   *                       transport will be closed.  If an Error is supplied as
+   *                       a rejection value, it will be logged via |dumpn|.  If
+   *                       you do use |copyFrom|, resolving is taken care of for
+   *                       you when copying completes.
+   *           * copyFrom: A helper function for getting your data onto the
+   *                       stream that meets the stream handling requirements
+   *                       above, and has the following signature:
+   *             @param  input nsIAsyncInputStream
+   *                     The stream to copy from.
+   *             @return Promise
+   *                     The promise is resolved when copying completes or
+   *                     rejected if any (unexpected) errors occur.
+   *                     This object also emits "progress" events for each chunk
+   *                     that is copied.  See stream-utils.js.
+   *         * json-reply: The server replied with a JSON packet, which is
+   *           passed as event data.
+   *         * bulk-reply: The server replied with bulk data, which you can read
+   *           using the event data object containing:
+   *           * actor:  Name of actor that received the packet
+   *           * type:   Name of actor's method that was called on receipt
+   *           * length: Size of the data to be read
+   *           * stream: This input stream should only be used directly if you
+   *                     can ensure that you will read exactly |length| bytes
+   *                     and will not close the stream when reading is complete
+   *           * done:   If you use the stream directly (instead of |copyTo|
+   *                     below), you must signal completion by resolving /
+   *                     rejecting this deferred.  If it's rejected, the
+   *                     transport will be closed.  If an Error is supplied as a
+   *                     rejection value, it will be logged via |dumpn|.  If you
+   *                     do use |copyTo|, resolving is taken care of for you
+   *                     when copying completes.
+   *           * copyTo: A helper function for getting your data out of the
+   *                     stream that meets the stream handling requirements
+   *                     above, and has the following signature:
+   *             @param  output nsIAsyncOutputStream
+   *                     The stream to copy to.
+   *             @return Promise
+   *                     The promise is resolved when copying completes or
+   *                     rejected if any (unexpected) errors occur.
+   *                     This object also emits "progress" events for each chunk
+   *                     that is copied.  See stream-utils.js.
+   */
+  startBulkRequest: function (request) {
+    if (!this.traits.bulk) {
+      throw Error("Server doesn't support bulk transfers");
+    }
+    if (!this.mainRoot) {
+      throw Error("Have not yet received a hello packet from the server.");
+    }
+    if (!request.type) {
+      throw Error("Bulk packet is missing the required 'type' field.");
+    }
+    if (!request.actor) {
+      throw Error("'" + request.type + "' bulk packet has no destination.");
+    }
+    if (!request.length) {
+      throw Error("'" + request.type + "' bulk packet has no length.");
+    }
+
+    request = new Request(request);
+    request.format = "bulk";
+
+    this._sendOrQueueRequest(request);
+
+    return request;
+  },
+
+  /**
+   * If a new request can be sent immediately, do so.  Otherwise, queue it.
+   */
+  _sendOrQueueRequest(request) {
+    let actor = request.actor;
+    if (!this._activeRequests.has(actor)) {
+      this._sendRequest(request);
+    } else {
+      this._queueRequest(request);
+    }
+  },
+
+  /**
+   * Send a request.
+   * @throws Error if there is already an active request in flight for the same
+   *         actor.
+   */
+  _sendRequest(request) {
+    let actor = request.actor;
+    this.expectReply(actor, request);
+
+    if (request.format === "json") {
+      this._transport.send(request.request);
+      return false;
+    }
+
+    this._transport.startBulkSend(request.request).then((...args) => {
+      request.emit("bulk-send-ready", ...args);
+    });
+  },
+
+  /**
+   * Queue a request to be sent later.  Queues are only drained when an in
+   * flight request to a given actor completes.
+   */
+  _queueRequest(request) {
+    let actor = request.actor;
+    let queue = this._pendingRequests.get(actor) || [];
+    queue.push(request);
+    this._pendingRequests.set(actor, queue);
+  },
+
+  /**
+   * Attempt the next request to a given actor (if any).
+   */
+  _attemptNextRequest(actor) {
+    if (this._activeRequests.has(actor)) {
+      return;
+    }
+    let queue = this._pendingRequests.get(actor);
+    if (!queue) {
+      return;
+    }
+    let request = queue.shift();
+    if (queue.length === 0) {
+      this._pendingRequests.delete(actor);
+    }
+    this._sendRequest(request);
+  },
+
+  /**
+   * Arrange to hand the next reply from |aActor| to the handler bound to
+   * |aRequest|.
+   *
+   * DebuggerClient.prototype.request / startBulkRequest usually takes care of
+   * establishing the handler for a given request, but in rare cases (well,
+   * greetings from new root actors, is the only case at the moment) we must be
+   * prepared for a "reply" that doesn't correspond to any request we sent.
+   */
+  expectReply: function (aActor, aRequest) {
+    if (this._activeRequests.has(aActor)) {
+      throw Error("clashing handlers for next reply from " + uneval(aActor));
+    }
+
+    // If a handler is passed directly (as it is with the handler for the root
+    // actor greeting), create a dummy request to bind this to.
+    if (typeof aRequest === "function") {
+      let handler = aRequest;
+      aRequest = new Request();
+      aRequest.on("json-reply", handler);
+    }
+
+    this._activeRequests.set(aActor, aRequest);
+  },
+
+  // Transport hooks.
+
+  /**
+   * Called by DebuggerTransport to dispatch incoming packets as appropriate.
+   *
+   * @param aPacket object
+   *        The incoming packet.
+   */
+  onPacket: function (aPacket) {
+    if (!aPacket.from) {
+      DevToolsUtils.reportException(
+        "onPacket",
+        new Error("Server did not specify an actor, dropping packet: " +
+                  JSON.stringify(aPacket)));
+      return;
+    }
+
+    // If we have a registered Front for this actor, let it handle the packet
+    // and skip all the rest of this unpleasantness.
+    let front = this.getActor(aPacket.from);
+    if (front) {
+      front.onPacket(aPacket);
+      return;
+    }
+
+    // Check for "forwardingCancelled" here instead of using a client to handle it.
+    // This is necessary because we might receive this event while the client is closing,
+    // and the clients have already been removed by that point.
+    if (this.mainRoot &&
+        aPacket.from == this.mainRoot.actor &&
+        aPacket.type == "forwardingCancelled") {
+      this.purgeRequests(aPacket.prefix);
+      return;
+    }
+
+    if (this._clients.has(aPacket.from) && aPacket.type) {
+      let client = this._clients.get(aPacket.from);
+      let type = aPacket.type;
+      if (client.events.indexOf(type) != -1) {
+        client.emit(type, aPacket);
+        // we ignore the rest, as the client is expected to handle this packet.
+        return;
+      }
+    }
+
+    let activeRequest;
+    // See if we have a handler function waiting for a reply from this
+    // actor. (Don't count unsolicited notifications or pauses as
+    // replies.)
+    if (this._activeRequests.has(aPacket.from) &&
+        !(aPacket.type in UnsolicitedNotifications) &&
+        !(aPacket.type == ThreadStateTypes.paused &&
+          aPacket.why.type in UnsolicitedPauses)) {
+      activeRequest = this._activeRequests.get(aPacket.from);
+      this._activeRequests.delete(aPacket.from);
+    }
+
+    // If there is a subsequent request for the same actor, hand it off to the
+    // transport.  Delivery of packets on the other end is always async, even
+    // in the local transport case.
+    this._attemptNextRequest(aPacket.from);
+
+    // Packets that indicate thread state changes get special treatment.
+    if (aPacket.type in ThreadStateTypes &&
+        this._clients.has(aPacket.from) &&
+        typeof this._clients.get(aPacket.from)._onThreadState == "function") {
+      this._clients.get(aPacket.from)._onThreadState(aPacket);
+    }
+
+    // TODO: Bug 1151156 - Remove once Gecko 40 is on b2g-stable.
+    if (!this.traits.noNeedToFakeResumptionOnNavigation) {
+      // On navigation the server resumes, so the client must resume as well.
+      // We achieve that by generating a fake resumption packet that triggers
+      // the client's thread state change listeners.
+      if (aPacket.type == UnsolicitedNotifications.tabNavigated &&
+          this._clients.has(aPacket.from) &&
+          this._clients.get(aPacket.from).thread) {
+        let thread = this._clients.get(aPacket.from).thread;
+        let resumption = { from: thread._actor, type: "resumed" };
+        thread._onThreadState(resumption);
+      }
+    }
+
+    // Only try to notify listeners on events, not responses to requests
+    // that lack a packet type.
+    if (aPacket.type) {
+      this.emit(aPacket.type, aPacket);
+    }
+
+    if (activeRequest) {
+      let emitReply = () => activeRequest.emit("json-reply", aPacket);
+      if (activeRequest.stack) {
+        callFunctionWithAsyncStack(emitReply, activeRequest.stack,
+                                   "DevTools RDP");
+      } else {
+        emitReply();
+      }
+    }
+  },
+
+  /**
+   * Called by the DebuggerTransport to dispatch incoming bulk packets as
+   * appropriate.
+   *
+   * @param packet object
+   *        The incoming packet, which contains:
+   *        * actor:  Name of actor that will receive the packet
+   *        * type:   Name of actor's method that should be called on receipt
+   *        * length: Size of the data to be read
+   *        * stream: This input stream should only be used directly if you can
+   *                  ensure that you will read exactly |length| bytes and will
+   *                  not close the stream when reading is complete
+   *        * done:   If you use the stream directly (instead of |copyTo|
+   *                  below), you must signal completion by resolving /
+   *                  rejecting this deferred.  If it's rejected, the transport
+   *                  will be closed.  If an Error is supplied as a rejection
+   *                  value, it will be logged via |dumpn|.  If you do use
+   *                  |copyTo|, resolving is taken care of for you when copying
+   *                  completes.
+   *        * copyTo: A helper function for getting your data out of the stream
+   *                  that meets the stream handling requirements above, and has
+   *                  the following signature:
+   *          @param  output nsIAsyncOutputStream
+   *                  The stream to copy to.
+   *          @return Promise
+   *                  The promise is resolved when copying completes or rejected
+   *                  if any (unexpected) errors occur.
+   *                  This object also emits "progress" events for each chunk
+   *                  that is copied.  See stream-utils.js.
+   */
+  onBulkPacket: function (packet) {
+    let { actor, type, length } = packet;
+
+    if (!actor) {
+      DevToolsUtils.reportException(
+        "onBulkPacket",
+        new Error("Server did not specify an actor, dropping bulk packet: " +
+                  JSON.stringify(packet)));
+      return;
+    }
+
+    // See if we have a handler function waiting for a reply from this
+    // actor.
+    if (!this._activeRequests.has(actor)) {
+      return;
+    }
+
+    let activeRequest = this._activeRequests.get(actor);
+    this._activeRequests.delete(actor);
+
+    // If there is a subsequent request for the same actor, hand it off to the
+    // transport.  Delivery of packets on the other end is always async, even
+    // in the local transport case.
+    this._attemptNextRequest(actor);
+
+    activeRequest.emit("bulk-reply", packet);
+  },
+
+  /**
+   * Called by DebuggerTransport when the underlying stream is closed.
+   *
+   * @param aStatus nsresult
+   *        The status code that corresponds to the reason for closing
+   *        the stream.
+   */
+  onClosed: function () {
+    this._closed = true;
+    this.emit("closed");
+
+    this.purgeRequests();
+
+    // The |_pools| array on the client-side currently is used only by
+    // protocol.js to store active fronts, mirroring the actor pools found in
+    // the server.  So, read all usages of "pool" as "protocol.js front".
+    //
+    // In the normal case where we shutdown cleanly, the toolbox tells each tool
+    // to close, and they each call |destroy| on any fronts they were using.
+    // When |destroy| or |cleanup| is called on a protocol.js front, it also
+    // removes itself from the |_pools| array.  Once the toolbox has shutdown,
+    // the connection is closed, and we reach here.  All fronts (should have
+    // been) |destroy|ed, so |_pools| should empty.
+    //
+    // If the connection instead aborts unexpectedly, we may end up here with
+    // all fronts used during the life of the connection.  So, we call |cleanup|
+    // on them clear their state, reject pending requests, and remove themselves
+    // from |_pools|.  This saves the toolbox from hanging indefinitely, in case
+    // it waits for some server response before shutdown that will now never
+    // arrive.
+    for (let pool of this._pools) {
+      pool.cleanup();
+    }
+  },
+
+  /**
+   * Purge pending and active requests in this client.
+   *
+   * @param prefix string (optional)
+   *        If a prefix is given, only requests for actor IDs that start with the prefix
+   *        will be cleaned up.  This is useful when forwarding of a portion of requests
+   *        is cancelled on the server.
+   */
+  purgeRequests(prefix = "") {
+    let reject = function (type, request) {
+      // Server can send packets on its own and client only pass a callback
+      // to expectReply, so that there is no request object.
+      let msg;
+      if (request.request) {
+        msg = "'" + request.request.type + "' " + type + " request packet" +
+              " to '" + request.actor + "' " +
+              "can't be sent as the connection just closed.";
+      } else {
+        msg = "server side packet can't be received as the connection just closed.";
+      }
+      let packet = { error: "connectionClosed", message: msg };
+      request.emit("json-reply", packet);
+    };
+
+    let pendingRequestsToReject = [];
+    this._pendingRequests.forEach((requests, actor) => {
+      if (!actor.startsWith(prefix)) {
+        return;
+      }
+      this._pendingRequests.delete(actor);
+      pendingRequestsToReject = pendingRequestsToReject.concat(requests);
+    });
+    pendingRequestsToReject.forEach(request => reject("pending", request));
+
+    let activeRequestsToReject = [];
+    this._activeRequests.forEach((request, actor) => {
+      if (!actor.startsWith(prefix)) {
+        return;
+      }
+      this._activeRequests.delete(actor);
+      activeRequestsToReject = activeRequestsToReject.concat(request);
+    });
+    activeRequestsToReject.forEach(request => reject("active", request));
+  },
+
+  registerClient: function (client) {
+    let actorID = client.actor;
+    if (!actorID) {
+      throw new Error("DebuggerServer.registerClient expects " +
+                      "a client instance with an `actor` attribute.");
+    }
+    if (!Array.isArray(client.events)) {
+      throw new Error("DebuggerServer.registerClient expects " +
+                      "a client instance with an `events` attribute " +
+                      "that is an array.");
+    }
+    if (client.events.length > 0 && typeof (client.emit) != "function") {
+      throw new Error("DebuggerServer.registerClient expects " +
+                      "a client instance with non-empty `events` array to" +
+                      "have an `emit` function.");
+    }
+    if (this._clients.has(actorID)) {
+      throw new Error("DebuggerServer.registerClient already registered " +
+                      "a client for this actor.");
+    }
+    this._clients.set(actorID, client);
+  },
+
+  unregisterClient: function (client) {
+    let actorID = client.actor;
+    if (!actorID) {
+      throw new Error("DebuggerServer.unregisterClient expects " +
+                      "a Client instance with a `actor` attribute.");
+    }
+    this._clients.delete(actorID);
+  },
+
+  /**
+   * Actor lifetime management, echos the server's actor pools.
+   */
+  __pools: null,
+  get _pools() {
+    if (this.__pools) {
+      return this.__pools;
+    }
+    this.__pools = new Set();
+    return this.__pools;
+  },
+
+  addActorPool: function (pool) {
+    this._pools.add(pool);
+  },
+  removeActorPool: function (pool) {
+    this._pools.delete(pool);
+  },
+  getActor: function (actorID) {
+    let pool = this.poolFor(actorID);
+    return pool ? pool.get(actorID) : null;
+  },
+
+  poolFor: function (actorID) {
+    for (let pool of this._pools) {
+      if (pool.has(actorID)) return pool;
+    }
+    return null;
+  },
+
+  /**
+   * Currently attached addon.
+   */
+  activeAddon: null
+};
+
+eventSource(DebuggerClient.prototype);
+
+function Request(request) {
+  this.request = request;
+}
+
+Request.prototype = {
+
+  on: function (type, listener) {
+    events.on(this, type, listener);
+  },
+
+  off: function (type, listener) {
+    events.off(this, type, listener);
+  },
+
+  once: function (type, listener) {
+    events.once(this, type, listener);
+  },
+
+  emit: function (type, ...args) {
+    events.emit(this, type, ...args);
+  },
+
+  get actor() { return this.request.to || this.request.actor; }
+
+};
+
+/**
+ * Creates a tab client for the remote debugging protocol server. This client
+ * is a front to the tab actor created in the server side, hiding the protocol
+ * details in a traditional JavaScript API.
+ *
+ * @param aClient DebuggerClient
+ *        The debugger client parent.
+ * @param aForm object
+ *        The protocol form for this tab.
+ */
+function TabClient(aClient, aForm) {
+  this.client = aClient;
+  this._actor = aForm.from;
+  this._threadActor = aForm.threadActor;
+  this.javascriptEnabled = aForm.javascriptEnabled;
+  this.cacheDisabled = aForm.cacheDisabled;
+  this.thread = null;
+  this.request = this.client.request;
+  this.traits = aForm.traits || {};
+  this.events = ["workerListChanged"];
+}
+
+TabClient.prototype = {
+  get actor() { return this._actor; },
+  get _transport() { return this.client._transport; },
+
+  /**
+   * Attach to a thread actor.
+   *
+   * @param object aOptions
+   *        Configuration options.
+   *        - useSourceMaps: whether to use source maps or not.
+   * @param function aOnResponse
+   *        Called with the response packet and a ThreadClient
+   *        (which will be undefined on error).
+   */
+  attachThread: function (aOptions = {}, aOnResponse = noop) {
+    if (this.thread) {
+      DevToolsUtils.executeSoon(() => aOnResponse({}, this.thread));
+      return promise.resolve([{}, this.thread]);
+    }
+
+    let packet = {
+      to: this._threadActor,
+      type: "attach",
+      options: aOptions
+    };
+    return this.request(packet).then(aResponse => {
+      if (!aResponse.error) {
+        this.thread = new ThreadClient(this, this._threadActor);
+        this.client.registerClient(this.thread);
+      }
+      aOnResponse(aResponse, this.thread);
+      return [aResponse, this.thread];
+    });
+  },
+
+  /**
+   * Detach the client from the tab actor.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  detach: DebuggerClient.requester({
+    type: "detach"
+  }, {
+    before: function (aPacket) {
+      if (this.thread) {
+        this.thread.detach();
+      }
+      return aPacket;
+    },
+    after: function (aResponse) {
+      this.client.unregisterClient(this);
+      return aResponse;
+    },
+  }),
+
+  /**
+   * Bring the window to the front.
+   */
+  focus: DebuggerClient.requester({
+    type: "focus"
+  }, {}),
+
+  /**
+   * Reload the page in this tab.
+   *
+   * @param [optional] object options
+   *        An object with a `force` property indicating whether or not
+   *        this reload should skip the cache
+   */
+  reload: function (options = { force: false }) {
+    return this._reload(options);
+  },
+  _reload: DebuggerClient.requester({
+    type: "reload",
+    options: args(0)
+  }),
+
+  /**
+   * Navigate to another URL.
+   *
+   * @param string url
+   *        The URL to navigate to.
+   */
+  navigateTo: DebuggerClient.requester({
+    type: "navigateTo",
+    url: args(0)
+  }),
+
+  /**
+   * Reconfigure the tab actor.
+   *
+   * @param object aOptions
+   *        A dictionary object of the new options to use in the tab actor.
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  reconfigure: DebuggerClient.requester({
+    type: "reconfigure",
+    options: args(0)
+  }),
+
+  listWorkers: DebuggerClient.requester({
+    type: "listWorkers"
+  }),
+
+  attachWorker: function (aWorkerActor, aOnResponse) {
+    this.client.attachWorker(aWorkerActor, aOnResponse);
+  },
+
+  /**
+   * Resolve a location ({ url, line, column }) to its current
+   * source mapping location.
+   *
+   * @param {String} arg[0].url
+   * @param {Number} arg[0].line
+   * @param {Number?} arg[0].column
+   */
+  resolveLocation: DebuggerClient.requester({
+    type: "resolveLocation",
+    location: args(0)
+  }),
+};
+
+eventSource(TabClient.prototype);
+
+function WorkerClient(aClient, aForm) {
+  this.client = aClient;
+  this._actor = aForm.from;
+  this._isClosed = false;
+  this._url = aForm.url;
+
+  this._onClose = this._onClose.bind(this);
+
+  this.addListener("close", this._onClose);
+
+  this.traits = {};
+}
+
+WorkerClient.prototype = {
+  get _transport() {
+    return this.client._transport;
+  },
+
+  get request() {
+    return this.client.request;
+  },
+
+  get actor() {
+    return this._actor;
+  },
+
+  get url() {
+    return this._url;
+  },
+
+  get isClosed() {
+    return this._isClosed;
+  },
+
+  detach: DebuggerClient.requester({ type: "detach" }, {
+    after: function (aResponse) {
+      if (this.thread) {
+        this.client.unregisterClient(this.thread);
+      }
+      this.client.unregisterClient(this);
+      return aResponse;
+    },
+  }),
+
+  attachThread: function (aOptions = {}, aOnResponse = noop) {
+    if (this.thread) {
+      let response = [{
+        type: "connected",
+        threadActor: this.thread._actor,
+        consoleActor: this.consoleActor,
+      }, this.thread];
+      DevToolsUtils.executeSoon(() => aOnResponse(response));
+      return response;
+    }
+
+    // The connect call on server doesn't attach the thread as of version 44.
+    return this.request({
+      to: this._actor,
+      type: "connect",
+      options: aOptions,
+    }).then(connectReponse => {
+      if (connectReponse.error) {
+        aOnResponse(connectReponse, null);
+        return [connectResponse, null];
+      }
+
+      return this.request({
+        to: connectReponse.threadActor,
+        type: "attach",
+        options: aOptions
+      }).then(attachResponse => {
+        if (attachResponse.error) {
+          aOnResponse(attachResponse, null);
+        }
+
+        this.thread = new ThreadClient(this, connectReponse.threadActor);
+        this.consoleActor = connectReponse.consoleActor;
+        this.client.registerClient(this.thread);
+
+        aOnResponse(connectReponse, this.thread);
+        return [connectResponse, this.thread];
+      });
+    }, error => {
+      aOnResponse(error, null);
+    });
+  },
+
+  _onClose: function () {
+    this.removeListener("close", this._onClose);
+
+    if (this.thread) {
+      this.client.unregisterClient(this.thread);
+    }
+    this.client.unregisterClient(this);
+    this._isClosed = true;
+  },
+
+  reconfigure: function () {
+    return Promise.resolve();
+  },
+
+  events: ["close"]
+};
+
+eventSource(WorkerClient.prototype);
+
+function AddonClient(aClient, aActor) {
+  this._client = aClient;
+  this._actor = aActor;
+  this.request = this._client.request;
+  this.events = [];
+}
+
+AddonClient.prototype = {
+  get actor() { return this._actor; },
+  get _transport() { return this._client._transport; },
+
+  /**
+   * Detach the client from the addon actor.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  detach: DebuggerClient.requester({
+    type: "detach"
+  }, {
+    after: function (aResponse) {
+      if (this._client.activeAddon === this) {
+        this._client.activeAddon = null;
+      }
+      this._client.unregisterClient(this);
+      return aResponse;
+    },
+  })
+};
+
+/**
+ * A RootClient object represents a root actor on the server. Each
+ * DebuggerClient keeps a RootClient instance representing the root actor
+ * for the initial connection; DebuggerClient's 'listTabs' and
+ * 'listChildProcesses' methods forward to that root actor.
+ *
+ * @param aClient object
+ *      The client connection to which this actor belongs.
+ * @param aGreeting string
+ *      The greeting packet from the root actor we're to represent.
+ *
+ * Properties of a RootClient instance:
+ *
+ * @property actor string
+ *      The name of this child's root actor.
+ * @property applicationType string
+ *      The application type, as given in the root actor's greeting packet.
+ * @property traits object
+ *      The traits object, as given in the root actor's greeting packet.
+ */
+function RootClient(aClient, aGreeting) {
+  this._client = aClient;
+  this.actor = aGreeting.from;
+  this.applicationType = aGreeting.applicationType;
+  this.traits = aGreeting.traits;
+}
+exports.RootClient = RootClient;
+
+RootClient.prototype = {
+  constructor: RootClient,
+
+  /**
+   * List the open tabs.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  listTabs: DebuggerClient.requester({ type: "listTabs" }),
+
+  /**
+   * List the installed addons.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  listAddons: DebuggerClient.requester({ type: "listAddons" }),
+
+  /**
+   * List the registered workers.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  listWorkers: DebuggerClient.requester({ type: "listWorkers" }),
+
+  /**
+   * List the registered service workers.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  listServiceWorkerRegistrations: DebuggerClient.requester({
+    type: "listServiceWorkerRegistrations"
+  }),
+
+  /**
+   * List the running processes.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  listProcesses: DebuggerClient.requester({ type: "listProcesses" }),
+
+  /**
+   * Fetch the TabActor for the currently selected tab, or for a specific
+   * tab given as first parameter.
+   *
+   * @param [optional] object aFilter
+   *        A dictionary object with following optional attributes:
+   *         - outerWindowID: used to match tabs in parent process
+   *         - tabId: used to match tabs in child processes
+   *         - tab: a reference to xul:tab element
+   *        If nothing is specified, returns the actor for the currently
+   *        selected tab.
+   */
+  getTab: function (aFilter) {
+    let packet = {
+      to: this.actor,
+      type: "getTab"
+    };
+
+    if (aFilter) {
+      if (typeof (aFilter.outerWindowID) == "number") {
+        packet.outerWindowID = aFilter.outerWindowID;
+      } else if (typeof (aFilter.tabId) == "number") {
+        packet.tabId = aFilter.tabId;
+      } else if ("tab" in aFilter) {
+        let browser = aFilter.tab.linkedBrowser;
+        if (browser.frameLoader.tabParent) {
+          // Tabs in child process
+          packet.tabId = browser.frameLoader.tabParent.tabId;
+        } else if (browser.outerWindowID) {
+          // <xul:browser> tabs in parent process
+          packet.outerWindowID = browser.outerWindowID;
+        } else {
+          // <iframe mozbrowser> tabs in parent process
+          let windowUtils = browser.contentWindow
+                                   .QueryInterface(Ci.nsIInterfaceRequestor)
+                                   .getInterface(Ci.nsIDOMWindowUtils);
+          packet.outerWindowID = windowUtils.outerWindowID;
+        }
+      } else {
+        // Throw if a filter object have been passed but without
+        // any clearly idenfified filter.
+        throw new Error("Unsupported argument given to getTab request");
+      }
+    }
+
+    return this.request(packet);
+  },
+
+  /**
+   * Description of protocol's actors and methods.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  protocolDescription: DebuggerClient.requester({ type: "protocolDescription" }),
+
+  /*
+   * Methods constructed by DebuggerClient.requester require these forwards
+   * on their 'this'.
+   */
+  get _transport() { return this._client._transport; },
+  get request() { return this._client.request; }
+};
+
+/**
+ * Creates a thread client for the remote debugging protocol server. This client
+ * is a front to the thread actor created in the server side, hiding the
+ * protocol details in a traditional JavaScript API.
+ *
+ * @param aClient DebuggerClient|TabClient
+ *        The parent of the thread (tab for tab-scoped debuggers, DebuggerClient
+ *        for chrome debuggers).
+ * @param aActor string
+ *        The actor ID for this thread.
+ */
+function ThreadClient(aClient, aActor) {
+  this._parent = aClient;
+  this.client = aClient instanceof DebuggerClient ? aClient : aClient.client;
+  this._actor = aActor;
+  this._frameCache = [];
+  this._scriptCache = {};
+  this._pauseGrips = {};
+  this._threadGrips = {};
+  this.request = this.client.request;
+}
+
+ThreadClient.prototype = {
+  _state: "paused",
+  get state() { return this._state; },
+  get paused() { return this._state === "paused"; },
+
+  _pauseOnExceptions: false,
+  _ignoreCaughtExceptions: false,
+  _pauseOnDOMEvents: null,
+
+  _actor: null,
+  get actor() { return this._actor; },
+
+  get _transport() { return this.client._transport; },
+
+  _assertPaused: function (aCommand) {
+    if (!this.paused) {
+      throw Error(aCommand + " command sent while not paused. Currently " + this._state);
+    }
+  },
+
+  /**
+   * Resume a paused thread. If the optional aLimit parameter is present, then
+   * the thread will also pause when that limit is reached.
+   *
+   * @param [optional] object aLimit
+   *        An object with a type property set to the appropriate limit (next,
+   *        step, or finish) per the remote debugging protocol specification.
+   *        Use null to specify no limit.
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  _doResume: DebuggerClient.requester({
+    type: "resume",
+    resumeLimit: args(0)
+  }, {
+    before: function (aPacket) {
+      this._assertPaused("resume");
+
+      // Put the client in a tentative "resuming" state so we can prevent
+      // further requests that should only be sent in the paused state.
+      this._previousState = this._state;
+      this._state = "resuming";
+
+      if (this._pauseOnExceptions) {
+        aPacket.pauseOnExceptions = this._pauseOnExceptions;
+      }
+      if (this._ignoreCaughtExceptions) {
+        aPacket.ignoreCaughtExceptions = this._ignoreCaughtExceptions;
+      }
+      if (this._pauseOnDOMEvents) {
+        aPacket.pauseOnDOMEvents = this._pauseOnDOMEvents;
+      }
+      return aPacket;
+    },
+    after: function (aResponse) {
+      if (aResponse.error && this._state == "resuming") {
+        // There was an error resuming, update the state to the new one
+        // reported by the server, if given (only on wrongState), otherwise
+        // reset back to the previous state.
+        if (aResponse.state) {
+          this._state = ThreadStateTypes[aResponse.state];
+        } else {
+          this._state = this._previousState;
+        }
+      }
+      delete this._previousState;
+      return aResponse;
+    },
+  }),
+
+  /**
+   * Reconfigure the thread actor.
+   *
+   * @param object aOptions
+   *        A dictionary object of the new options to use in the thread actor.
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  reconfigure: DebuggerClient.requester({
+    type: "reconfigure",
+    options: args(0)
+  }),
+
+  /**
+   * Resume a paused thread.
+   */
+  resume: function (aOnResponse) {
+    return this._doResume(null, aOnResponse);
+  },
+
+  /**
+   * Resume then pause without stepping.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  resumeThenPause: function (aOnResponse) {
+    return this._doResume({ type: "break" }, aOnResponse);
+  },
+
+  /**
+   * Step over a function call.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  stepOver: function (aOnResponse) {
+    return this._doResume({ type: "next" }, aOnResponse);
+  },
+
+  /**
+   * Step into a function call.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  stepIn: function (aOnResponse) {
+    return this._doResume({ type: "step" }, aOnResponse);
+  },
+
+  /**
+   * Step out of a function call.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  stepOut: function (aOnResponse) {
+    return this._doResume({ type: "finish" }, aOnResponse);
+  },
+
+  /**
+   * Immediately interrupt a running thread.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  interrupt: function (aOnResponse) {
+    return this._doInterrupt(null, aOnResponse);
+  },
+
+  /**
+   * Pause execution right before the next JavaScript bytecode is executed.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  breakOnNext: function (aOnResponse) {
+    return this._doInterrupt("onNext", aOnResponse);
+  },
+
+  /**
+   * Interrupt a running thread.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  _doInterrupt: DebuggerClient.requester({
+    type: "interrupt",
+    when: args(0)
+  }),
+
+  /**
+   * Enable or disable pausing when an exception is thrown.
+   *
+   * @param boolean aFlag
+   *        Enables pausing if true, disables otherwise.
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  pauseOnExceptions: function (aPauseOnExceptions,
+                               aIgnoreCaughtExceptions,
+                               aOnResponse = noop) {
+    this._pauseOnExceptions = aPauseOnExceptions;
+    this._ignoreCaughtExceptions = aIgnoreCaughtExceptions;
+
+    // Otherwise send the flag using a standard resume request.
+    if (!this.paused) {
+      return this.interrupt(aResponse => {
+        if (aResponse.error) {
+          // Can't continue if pausing failed.
+          aOnResponse(aResponse);
+          return aResponse;
+        }
+        return this.resume(aOnResponse);
+      });
+    }
+
+    aOnResponse();
+    return promise.resolve();
+  },
+
+  /**
+   * Enable pausing when the specified DOM events are triggered. Disabling
+   * pausing on an event can be realized by calling this method with the updated
+   * array of events that doesn't contain it.
+   *
+   * @param array|string events
+   *        An array of strings, representing the DOM event types to pause on,
+   *        or "*" to pause on all DOM events. Pass an empty array to
+   *        completely disable pausing on DOM events.
+   * @param function onResponse
+   *        Called with the response packet in a future turn of the event loop.
+   */
+  pauseOnDOMEvents: function (events, onResponse = noop) {
+    this._pauseOnDOMEvents = events;
+    // If the debuggee is paused, the value of the array will be communicated in
+    // the next resumption. Otherwise we have to force a pause in order to send
+    // the array.
+    if (this.paused) {
+      DevToolsUtils.executeSoon(() => onResponse({}));
+      return {};
+    }
+    return this.interrupt(response => {
+      // Can't continue if pausing failed.
+      if (response.error) {
+        onResponse(response);
+        return response;
+      }
+      return this.resume(onResponse);
+    });
+  },
+
+  /**
+   * Send a clientEvaluate packet to the debuggee. Response
+   * will be a resume packet.
+   *
+   * @param string aFrame
+   *        The actor ID of the frame where the evaluation should take place.
+   * @param string aExpression
+   *        The expression that will be evaluated in the scope of the frame
+   *        above.
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  eval: DebuggerClient.requester({
+    type: "clientEvaluate",
+    frame: args(0),
+    expression: args(1)
+  }, {
+    before: function (aPacket) {
+      this._assertPaused("eval");
+      // Put the client in a tentative "resuming" state so we can prevent
+      // further requests that should only be sent in the paused state.
+      this._state = "resuming";
+      return aPacket;
+    },
+    after: function (aResponse) {
+      if (aResponse.error) {
+        // There was an error resuming, back to paused state.
+        this._state = "paused";
+      }
+      return aResponse;
+    },
+  }),
+
+  /**
+   * Detach from the thread actor.
+   *
+   * @param function aOnResponse
+   *        Called with the response packet.
+   */
+  detach: DebuggerClient.requester({
+    type: "detach"
+  }, {
+    after: function (aResponse) {
+      this.client.unregisterClient(this);
+      this._parent.thread = null;
+      return aResponse;
+    },
+  }),
+
+  /**
+   * Release multiple thread-lifetime object actors. If any pause-lifetime
+   * actors are included in the request, a |notReleasable| error will return,
+   * but all the thread-lifetime ones will have been released.
+   *
+   * @param array actors
+   *        An array with actor IDs to release.
+   */
+  releaseMany: DebuggerClient.requester({
+    type: "releaseMany",
+    actors: args(0),
+  }),
+
+  /**
+   * Promote multiple pause-lifetime object actors to thread-lifetime ones.
+   *
+   * @param array actors
+   *        An array with actor IDs to promote.
+   */
+  threadGrips: DebuggerClient.requester({
+    type: "threadGrips",
+    actors: args(0)
+  }),
+
+  /**
+   * Return the event listeners defined on the page.
+   *
+   * @param aOnResponse Function
+   *        Called with the thread's response.
+   */
+  eventListeners: DebuggerClient.requester({
+    type: "eventListeners"
+  }),
+
+  /**
+   * Request the loaded sources for the current thread.
+   *
+   * @param aOnResponse Function
+   *        Called with the thread's response.
+   */
+  getSources: DebuggerClient.requester({
+    type: "sources"
+  }),
+
+  /**
+   * Clear the thread's source script cache. A scriptscleared event
+   * will be sent.
+   */
+  _clearScripts: function () {
+    if (Object.keys(this._scriptCache).length > 0) {
+      this._scriptCache = {};
+      this.emit("scriptscleared");
+    }
+  },
+
+  /**
+   * Request frames from the callstack for the current thread.
+   *
+   * @param aStart integer
+   *        The number of the youngest stack frame to return (the youngest
+   *        frame is 0).
+   * @param aCount integer
+   *        The maximum number of frames to return, or null to return all
+   *        frames.
+   * @param aOnResponse function
+   *        Called with the thread's response.
+   */
+  getFrames: DebuggerClient.requester({
+    type: "frames",
+    start: args(0),
+    count: args(1)
+  }),
+
+  /**
+   * An array of cached frames. Clients can observe the framesadded and
+   * framescleared event to keep up to date on changes to this cache,
+   * and can fill it using the fillFrames method.
+   */
+  get cachedFrames() { return this._frameCache; },
+
+  /**
+   * true if there are more stack frames available on the server.
+   */
+  get moreFrames() {
+    return this.paused && (!this._frameCache || this._frameCache.length == 0
+          || !this._frameCache[this._frameCache.length - 1].oldest);
+  },
+
+  /**
+   * Ensure that at least aTotal stack frames have been loaded in the
+   * ThreadClient's stack frame cache. A framesadded event will be
+   * sent when the stack frame cache is updated.
+   *
+   * @param aTotal number
+   *        The minimum number of stack frames to be included.
+   * @param aCallback function
+   *        Optional callback function called when frames have been loaded
+   * @returns true if a framesadded notification should be expected.
+   */
+  fillFrames: function (aTotal, aCallback = noop) {
+    this._assertPaused("fillFrames");
+    if (this._frameCache.length >= aTotal) {
+      return false;
+    }
+
+    let numFrames = this._frameCache.length;
+
+    this.getFrames(numFrames, aTotal - numFrames, (aResponse) => {
+      if (aResponse.error) {
+        aCallback(aResponse);
+        return;
+      }
+
+      let threadGrips = DevToolsUtils.values(this._threadGrips);
+
+      for (let i in aResponse.frames) {
+        let frame = aResponse.frames[i];
+        if (!frame.where.source) {
+          // Older servers use urls instead, so we need to resolve
+          // them to source actors
+          for (let grip of threadGrips) {
+            if (grip instanceof SourceClient && grip.url === frame.url) {
+              frame.where.source = grip._form;
+            }
+          }
+        }
+
+        this._frameCache[frame.depth] = frame;
+      }
+
+      // If we got as many frames as we asked for, there might be more
+      // frames available.
+      this.emit("framesadded");
+
+      aCallback(aResponse);
+    });
+
+    return true;
+  },
+
+  /**
+   * Clear the thread's stack frame cache. A framescleared event
+   * will be sent.
+   */
+  _clearFrames: function () {
+    if (this._frameCache.length > 0) {
+      this._frameCache = [];
+      this.emit("framescleared");
+    }
+  },
+
+  /**
+   * Return a ObjectClient object for the given object grip.
+   *
+   * @param aGrip object
+   *        A pause-lifetime object grip returned by the protocol.
+   */
+  pauseGrip: function (aGrip) {
+    if (aGrip.actor in this._pauseGrips) {
+      return this._pauseGrips[aGrip.actor];
+    }
+
+    let client = new ObjectClient(this.client, aGrip);
+    this._pauseGrips[aGrip.actor] = client;
+    return client;
+  },
+
+  /**
+   * Get or create a long string client, checking the grip client cache if it
+   * already exists.
+   *
+   * @param aGrip Object
+   *        The long string grip returned by the protocol.
+   * @param aGripCacheName String
+   *        The property name of the grip client cache to check for existing
+   *        clients in.
+   */
+  _longString: function (aGrip, aGripCacheName) {
+    if (aGrip.actor in this[aGripCacheName]) {
+      return this[aGripCacheName][aGrip.actor];
+    }
+
+    let client = new LongStringClient(this.client, aGrip);
+    this[aGripCacheName][aGrip.actor] = client;
+    return client;
+  },
+
+  /**
+   * Return an instance of LongStringClient for the given long string grip that
+   * is scoped to the current pause.
+   *
+   * @param aGrip Object
+   *        The long string grip returned by the protocol.
+   */
+  pauseLongString: function (aGrip) {
+    return this._longString(aGrip, "_pauseGrips");
+  },
+
+  /**
+   * Return an instance of LongStringClient for the given long string grip that
+   * is scoped to the thread lifetime.
+   *
+   * @param aGrip Object
+   *        The long string grip returned by the protocol.
+   */
+  threadLongString: function (aGrip) {
+    return this._longString(aGrip, "_threadGrips");
+  },
+
+  /**
+   * Clear and invalidate all the grip clients from the given cache.
+   *
+   * @param aGripCacheName
+   *        The property name of the grip cache we want to clear.
+   */
+  _clearObjectClients: function (aGripCacheName) {
+    for (let id in this[aGripCacheName]) {
+      this[aGripCacheName][id].valid = false;
+    }
+    this[aGripCacheName] = {};
+  },
+
+  /**
+   * Invalidate pause-lifetime grip clients and clear the list of current grip
+   * clients.
+   */
+  _clearPauseGrips: function () {
+    this._clearObjectClients("_pauseGrips");
+  },
+
+  /**
+   * Invalidate thread-lifetime grip clients and clear the list of current grip
+   * clients.
+   */
+  _clearThreadGrips: function () {
+    this._clearObjectClients("_threadGrips");
+  },
+
+  /**
+   * Handle thread state change by doing necessary cleanup and notifying all
+   * registered listeners.
+   */
+  _onThreadState: function (aPacket) {
+    this._state = ThreadStateTypes[aPacket.type];
+    // The debugger UI may not be initialized yet so we want to keep
+    // the packet around so it knows what to pause state to display
+    // when it's initialized
+    this._lastPausePacket = aPacket.type === "resumed" ? null : aPacket;
+    this._clearFrames();
+    this._clearPauseGrips();
+    aPacket.type === ThreadStateTypes.detached && this._clearThreadGrips();
+    this.client._eventsEnabled && this.emit(aPacket.type, aPacket);
+  },
+
+  getLastPausePacket: function () {
+    return this._lastPausePacket;
+  },
+
+  /**
+   * Return an EnvironmentClient instance for the given environment actor form.
+   */
+  environment: function (aForm) {
+    return new EnvironmentClient(this.client, aForm);
+  },
+
+  /**
+   * Return an instance of SourceClient for the given source actor form.
+   */
+  source: function (aForm) {
+    if (aForm.actor in this._threadGrips) {
+      return this._threadGrips[aForm.actor];
+    }
+
+    return this._threadGrips[aForm.actor] = new SourceClient(this, aForm);
+  },
+
+  /**
+   * Request the prototype and own properties of mutlipleObjects.
+   *
+   * @param aOnResponse function
+   *        Called with the request's response.
+   * @param actors [string]
+   *        List of actor ID of the queried objects.
+   */
+  getPrototypesAndProperties: DebuggerClient.requester({
+    type: "prototypesAndProperties",
+    actors: args(0)
+  }),
+
+  events: ["newSource"]
+};
+
+eventSource(ThreadClient.prototype);
+
+/**
+ * Creates a tracing profiler client for the remote debugging protocol
+ * server. This client is a front to the trace actor created on the
+ * server side, hiding the protocol details in a traditional
+ * JavaScript API.
+ *
+ * @param aClient DebuggerClient
+ *        The debugger client parent.
+ * @param aActor string
+ *        The actor ID for this thread.
+ */
+function TraceClient(aClient, aActor) {
+  this._client = aClient;
+  this._actor = aActor;
+  this._activeTraces = new Set();
+  this._waitingPackets = new Map();
+  this._expectedPacket = 0;
+  this.request = this._client.request;
+  this.events = [];
+}
+
+TraceClient.prototype = {
+  get actor() { return this._actor; },
+  get tracing() { return this._activeTraces.size > 0; },
+
+  get _transport() { return this._client._transport; },
+
+  /**
+   * Detach from the trace actor.
+   */
+  detach: DebuggerClient.requester({
+    type: "detach"
+  }, {
+    after: function (aResponse) {
+      this._client.unregisterClient(this);
+      return aResponse;
+    },
+  }),
+
+  /**
+   * Start a new trace.
+   *
+   * @param aTrace [string]
+   *        An array of trace types to be recorded by the new trace.
+   *
+   * @param aName string
+   *        The name of the new trace.
+   *
+   * @param aOnResponse function
+   *        Called with the request's response.
+   */
+  startTrace: DebuggerClient.requester({
+    type: "startTrace",
+    name: args(1),
+    trace: args(0)
+  }, {
+    after: function (aResponse) {
+      if (aResponse.error) {
+        return aResponse;
+      }
+
+      if (!this.tracing) {
+        this._waitingPackets.clear();
+        this._expectedPacket = 0;
+      }
+      this._activeTraces.add(aResponse.name);
+
+      return aResponse;
+    },
+  }),
+
+  /**
+   * End a trace. If a name is provided, stop the named
+   * trace. Otherwise, stop the most recently started trace.
+   *
+   * @param aName string
+   *        The name of the trace to stop.
+   *
+   * @param aOnResponse function
+   *        Called with the request's response.
+   */
+  stopTrace: DebuggerClient.requester({
+    type: "stopTrace",
+    name: args(0)
+  }, {
+    after: function (aResponse) {
+      if (aResponse.error) {
+        return aResponse;
+      }
+
+      this._activeTraces.delete(aResponse.name);
+
+      return aResponse;
+    },
+  })
+};
+
+/**
+ * Grip clients are used to retrieve information about the relevant object.
+ *
+ * @param aClient DebuggerClient
+ *        The debugger client parent.
+ * @param aGrip object
+ *        A pause-lifetime object grip returned by the protocol.
+ */
+function ObjectClient(aClient, aGrip)
+{
+  this._grip = aGrip;
+  this._client = aClient;
+  this.request = this._client.request;
+}
+exports.ObjectClient = ObjectClient;
+
+ObjectClient.prototype = {
+  get actor() { return this._grip.actor; },
+  get _transport() { return this._client._transport; },
+
+  valid: true,
+
+  get isFrozen() {
+    return this._grip.frozen;
+  },
+  get isSealed() {
+    return this._grip.sealed;
+  },
+  get isExtensible() {
+    return this._grip.extensible;
+  },
+
+  getDefinitionSite: DebuggerClient.requester({
+    type: "definitionSite"
+  }, {
+    before: function (aPacket) {
+      if (this._grip.class != "Function") {
+        throw new Error("getDefinitionSite is only valid for function grips.");
+      }
+      return aPacket;
+    }
+  }),
+
+  /**
+   * Request the names of a function's formal parameters.
+   *
+   * @param aOnResponse function
+   *        Called with an object of the form:
+   *        { parameterNames:[<parameterName>, ...] }
+   *        where each <parameterName> is the name of a parameter.
+   */
+  getParameterNames: DebuggerClient.requester({
+    type: "parameterNames"
+  }, {
+    before: function (aPacket) {
+      if (this._grip["class"] !== "Function") {
+        throw new Error("getParameterNames is only valid for function grips.");
+      }
+      return aPacket;
+    },
+  }),
+
+  /**
+   * Request the names of the properties defined on the object and not its
+   * prototype.
+   *
+   * @param aOnResponse function Called with the request's response.
+   */
+  getOwnPropertyNames: DebuggerClient.requester({
+    type: "ownPropertyNames"
+  }),
+
+  /**
+   * Request the prototype and own properties of the object.
+   *
+   * @param aOnResponse function Called with the request's response.
+   */
+  getPrototypeAndProperties: DebuggerClient.requester({
+    type: "prototypeAndProperties"
+  }),
+
+  /**
+   * Request a PropertyIteratorClient instance to ease listing
+   * properties for this object.
+   *
+   * @param options Object
+   *        A dictionary object with various boolean attributes:
+   *        - ignoreIndexedProperties Boolean
+   *          If true, filters out Array items.
+   *          e.g. properties names between `0` and `object.length`.
+   *        - ignoreNonIndexedProperties Boolean
+   *          If true, filters out items that aren't array items
+   *          e.g. properties names that are not a number between `0`
+   *          and `object.length`.
+   *        - sort Boolean
+   *          If true, the iterator will sort the properties by name
+   *          before dispatching them.
+   * @param aOnResponse function Called with the client instance.
+   */
+  enumProperties: DebuggerClient.requester({
+    type: "enumProperties",
+    options: args(0)
+  }, {
+    after: function (aResponse) {
+      if (aResponse.iterator) {
+        return { iterator: new PropertyIteratorClient(this._client, aResponse.iterator) };
+      }
+      return aResponse;
+    },
+  }),
+
+  /**
+   * Request a PropertyIteratorClient instance to enumerate entries in a
+   * Map/Set-like object.
+   *
+   * @param aOnResponse function Called with the request's response.
+   */
+  enumEntries: DebuggerClient.requester({
+    type: "enumEntries"
+  }, {
+    before: function (packet) {
+      if (!["Map", "WeakMap", "Set", "WeakSet"].includes(this._grip.class)) {
+        throw new Error("enumEntries is only valid for Map/Set-like grips.");
+      }
+      return packet;
+    },
+    after: function (response) {
+      if (response.iterator) {
+        return {
+          iterator: new PropertyIteratorClient(this._client, response.iterator)
+        };
+      }
+      return response;
+    }
+  }),
+
+  /**
+   * Request the property descriptor of the object's specified property.
+   *
+   * @param aName string The name of the requested property.
+   * @param aOnResponse function Called with the request's response.
+   */
+  getProperty: DebuggerClient.requester({
+    type: "property",
+    name: args(0)
+  }),
+
+  /**
+   * Request the prototype of the object.
+   *
+   * @param aOnResponse function Called with the request's response.
+   */
+  getPrototype: DebuggerClient.requester({
+    type: "prototype"
+  }),
+
+  /**
+   * Request the display string of the object.
+   *
+   * @param aOnResponse function Called with the request's response.
+   */
+  getDisplayString: DebuggerClient.requester({
+    type: "displayString"
+  }),
+
+  /**
+   * Request the scope of the object.
+   *
+   * @param aOnResponse function Called with the request's response.
+   */
+  getScope: DebuggerClient.requester({
+    type: "scope"
+  }, {
+    before: function (aPacket) {
+      if (this._grip.class !== "Function") {
+        throw new Error("scope is only valid for function grips.");
+      }
+      return aPacket;
+    },
+  }),
+
+  /**
+   * Request the promises directly depending on the current promise.
+   */
+  getDependentPromises: DebuggerClient.requester({
+    type: "dependentPromises"
+  }, {
+    before: function (aPacket) {
+      if (this._grip.class !== "Promise") {
+        throw new Error("getDependentPromises is only valid for promise " +
+          "grips.");
+      }
+      return aPacket;
+    }
+  }),
+
+  /**
+   * Request the stack to the promise's allocation point.
+   */
+  getPromiseAllocationStack: DebuggerClient.requester({
+    type: "allocationStack"
+  }, {
+    before: function (aPacket) {
+      if (this._grip.class !== "Promise") {
+        throw new Error("getAllocationStack is only valid for promise grips.");
+      }
+      return aPacket;
+    }
+  }),
+
+  /**
+   * Request the stack to the promise's fulfillment point.
+   */
+  getPromiseFulfillmentStack: DebuggerClient.requester({
+    type: "fulfillmentStack"
+  }, {
+    before: function (packet) {
+      if (this._grip.class !== "Promise") {
+        throw new Error("getPromiseFulfillmentStack is only valid for " +
+          "promise grips.");
+      }
+      return packet;
+    }
+  }),
+
+  /**
+   * Request the stack to the promise's rejection point.
+   */
+  getPromiseRejectionStack: DebuggerClient.requester({
+    type: "rejectionStack"
+  }, {
+    before: function (packet) {
+      if (this._grip.class !== "Promise") {
+        throw new Error("getPromiseRejectionStack is only valid for " +
+          "promise grips.");
+      }
+      return packet;
+    }
+  })
+};
+
+/**
+ * A PropertyIteratorClient provides a way to access to property names and
+ * values of an object efficiently, slice by slice.
+ * Note that the properties can be sorted in the backend,
+ * this is controled while creating the PropertyIteratorClient
+ * from ObjectClient.enumProperties.
+ *
+ * @param aClient DebuggerClient
+ *        The debugger client parent.
+ * @param aGrip Object
+ *        A PropertyIteratorActor grip returned by the protocol via
+ *        TabActor.enumProperties request.
+ */
+function PropertyIteratorClient(aClient, aGrip) {
+  this._grip = aGrip;
+  this._client = aClient;
+  this.request = this._client.request;
+}
+
+PropertyIteratorClient.prototype = {
+  get actor() { return this._grip.actor; },
+
+  /**
+   * Get the total number of properties available in the iterator.
+   */
+  get count() { return this._grip.count; },
+
+  /**
+   * Get one or more property names that correspond to the positions in the
+   * indexes parameter.
+   *
+   * @param indexes Array
+   *        An array of property indexes.
+   * @param aCallback Function
+   *        The function called when we receive the property names.
+   */
+  names: DebuggerClient.requester({
+    type: "names",
+    indexes: args(0)
+  }, {}),
+
+  /**
+   * Get a set of following property value(s).
+   *
+   * @param start Number
+   *        The index of the first property to fetch.
+   * @param count Number
+   *        The number of properties to fetch.
+   * @param aCallback Function
+   *        The function called when we receive the property values.
+   */
+  slice: DebuggerClient.requester({
+    type: "slice",
+    start: args(0),
+    count: args(1)
+  }, {}),
+
+  /**
+   * Get all the property values.
+   *
+   * @param aCallback Function
+   *        The function called when we receive the property values.
+   */
+  all: DebuggerClient.requester({
+    type: "all"
+  }, {}),
+};
+
+/**
+ * A LongStringClient provides a way to access "very long" strings from the
+ * debugger server.
+ *
+ * @param aClient DebuggerClient
+ *        The debugger client parent.
+ * @param aGrip Object
+ *        A pause-lifetime long string grip returned by the protocol.
+ */
+function LongStringClient(aClient, aGrip) {
+  this._grip = aGrip;
+  this._client = aClient;
+  this.request = this._client.request;
+}
+exports.LongStringClient = LongStringClient;
+
+LongStringClient.prototype = {
+  get actor() { return this._grip.actor; },
+  get length() { return this._grip.length; },
+  get initial() { return this._grip.initial; },
+  get _transport() { return this._client._transport; },
+
+  valid: true,
+
+  /**
+   * Get the substring of this LongString from aStart to aEnd.
+   *
+   * @param aStart Number
+   *        The starting index.
+   * @param aEnd Number
+   *        The ending index.
+   * @param aCallback Function
+   *        The function called when we receive the substring.
+   */
+  substring: DebuggerClient.requester({
+    type: "substring",
+    start: args(0),
+    end: args(1)
+  }),
+};
+
+/**
+ * A SourceClient provides a way to access the source text of a script.
+ *
+ * @param aClient ThreadClient
+ *        The thread client parent.
+ * @param aForm Object
+ *        The form sent across the remote debugging protocol.
+ */
+function SourceClient(aClient, aForm) {
+  this._form = aForm;
+  this._isBlackBoxed = aForm.isBlackBoxed;
+  this._isPrettyPrinted = aForm.isPrettyPrinted;
+  this._activeThread = aClient;
+  this._client = aClient.client;
+}
+
+SourceClient.prototype = {
+  get _transport() {
+    return this._client._transport;
+  },
+  get isBlackBoxed() {
+    return this._isBlackBoxed;
+  },
+  get isPrettyPrinted() {
+    return this._isPrettyPrinted;
+  },
+  get actor() {
+    return this._form.actor;
+  },
+  get request() {
+    return this._client.request;
+  },
+  get url() {
+    return this._form.url;
+  },
+
+  /**
+   * Black box this SourceClient's source.
+   *
+   * @param aCallback Function
+   *        The callback function called when we receive the response from the server.
+   */
+  blackBox: DebuggerClient.requester({
+    type: "blackbox"
+  }, {
+    after: function (aResponse) {
+      if (!aResponse.error) {
+        this._isBlackBoxed = true;
+        if (this._activeThread) {
+          this._activeThread.emit("blackboxchange", this);
+        }
+      }
+      return aResponse;
+    }
+  }),
+
+  /**
+   * Un-black box this SourceClient's source.
+   *
+   * @param aCallback Function
+   *        The callback function called when we receive the response from the server.
+   */
+  unblackBox: DebuggerClient.requester({
+    type: "unblackbox"
+  }, {
+    after: function (aResponse) {
+      if (!aResponse.error) {
+        this._isBlackBoxed = false;
+        if (this._activeThread) {
+          this._activeThread.emit("blackboxchange", this);
+        }
+      }
+      return aResponse;
+    }
+  }),
+
+  /**
+   * Get Executable Lines from a source
+   *
+   * @param aCallback Function
+   *        The callback function called when we receive the response from the server.
+   */
+  getExecutableLines: function (cb = noop) {
+    let packet = {
+      to: this._form.actor,
+      type: "getExecutableLines"
+    };
+
+    return this._client.request(packet).then(res => {
+      cb(res.lines);
+      return res.lines;
+    });
+  },
+
+  /**
+   * Get a long string grip for this SourceClient's source.
+   */
+  source: function (aCallback = noop) {
+    let packet = {
+      to: this._form.actor,
+      type: "source"
+    };
+    return this._client.request(packet).then(aResponse => {
+      return this._onSourceResponse(aResponse, aCallback);
+    });
+  },
+
+  /**
+   * Pretty print this source's text.
+   */
+  prettyPrint: function (aIndent, aCallback = noop) {
+    const packet = {
+      to: this._form.actor,
+      type: "prettyPrint",
+      indent: aIndent
+    };
+    return this._client.request(packet).then(aResponse => {
+      if (!aResponse.error) {
+        this._isPrettyPrinted = true;
+        this._activeThread._clearFrames();
+        this._activeThread.emit("prettyprintchange", this);
+      }
+      return this._onSourceResponse(aResponse, aCallback);
+    });
+  },
+
+  /**
+   * Stop pretty printing this source's text.
+   */
+  disablePrettyPrint: function (aCallback = noop) {
+    const packet = {
+      to: this._form.actor,
+      type: "disablePrettyPrint"
+    };
+    return this._client.request(packet).then(aResponse => {
+      if (!aResponse.error) {
+        this._isPrettyPrinted = false;
+        this._activeThread._clearFrames();
+        this._activeThread.emit("prettyprintchange", this);
+      }
+      return this._onSourceResponse(aResponse, aCallback);
+    });
+  },
+
+  _onSourceResponse: function (aResponse, aCallback) {
+    if (aResponse.error) {
+      aCallback(aResponse);
+      return aResponse;
+    }
+
+    if (typeof aResponse.source === "string") {
+      aCallback(aResponse);
+      return aResponse;
+    }
+
+    let { contentType, source } = aResponse;
+    let longString = this._activeThread.threadLongString(source);
+    return longString.substring(0, longString.length).then(function (aResponse) {
+      if (aResponse.error) {
+        aCallback(aResponse);
+        return aReponse;
+      }
+
+      let response = {
+        source: aResponse.substring,
+        contentType: contentType
+      };
+      aCallback(response);
+      return response;
+    });
+  },
+
+  /**
+   * Request to set a breakpoint in the specified location.
+   *
+   * @param object aLocation
+   *        The location and condition of the breakpoint in
+   *        the form of { line[, column, condition] }.
+   * @param function aOnResponse
+   *        Called with the thread's response.
+   */
+  setBreakpoint: function ({ line, column, condition, noSliding }, aOnResponse = noop) {
+    // A helper function that sets the breakpoint.
+    let doSetBreakpoint = aCallback => {
+      let root = this._client.mainRoot;
+      let location = {
+        line: line,
+        column: column
+      };
+
+      let packet = {
+        to: this.actor,
+        type: "setBreakpoint",
+        location: location,
+        condition: condition,
+        noSliding: noSliding
+      };
+
+      // Backwards compatibility: send the breakpoint request to the
+      // thread if the server doesn't support Debugger.Source actors.
+      if (!root.traits.debuggerSourceActors) {
+        packet.to = this._activeThread.actor;
+        packet.location.url = this.url;
+      }
+
+      return this._client.request(packet).then(aResponse => {
+        // Ignoring errors, since the user may be setting a breakpoint in a
+        // dead script that will reappear on a page reload.
+        let bpClient;
+        if (aResponse.actor) {
+          bpClient = new BreakpointClient(
+            this._client,
+            this,
+            aResponse.actor,
+            location,
+            root.traits.conditionalBreakpoints ? condition : undefined
+          );
+        }
+        aOnResponse(aResponse, bpClient);
+        if (aCallback) {
+          aCallback();
+        }
+        return [aResponse, bpClient];
+      });
+    };
+
+    // If the debuggee is paused, just set the breakpoint.
+    if (this._activeThread.paused) {
+      return doSetBreakpoint();
+    }
+    // Otherwise, force a pause in order to set the breakpoint.
+    return this._activeThread.interrupt().then(aResponse => {
+      if (aResponse.error) {
+        // Can't set the breakpoint if pausing failed.
+        aOnResponse(aResponse);
+        return aResponse;
+      }
+
+      const { type, why } = aResponse;
+      const cleanUp = type == "paused" && why.type == "interrupted"
+            ? () => this._activeThread.resume()
+            : noop;
+
+      return doSetBreakpoint(cleanUp);
+    });
+  }
+};
+
+/**
+ * Breakpoint clients are used to remove breakpoints that are no longer used.
+ *
+ * @param aClient DebuggerClient
+ *        The debugger client parent.
+ * @param aSourceClient SourceClient
+ *        The source where this breakpoint exists
+ * @param aActor string
+ *        The actor ID for this breakpoint.
+ * @param aLocation object
+ *        The location of the breakpoint. This is an object with two properties:
+ *        url and line.
+ * @param aCondition string
+ *        The conditional expression of the breakpoint
+ */
+function BreakpointClient(aClient, aSourceClient, aActor, aLocation, aCondition) {
+  this._client = aClient;
+  this._actor = aActor;
+  this.location = aLocation;
+  this.location.actor = aSourceClient.actor;
+  this.location.url = aSourceClient.url;
+  this.source = aSourceClient;
+  this.request = this._client.request;
+
+  // The condition property should only exist if it's a truthy value
+  if (aCondition) {
+    this.condition = aCondition;
+  }
+}
+
+BreakpointClient.prototype = {
+
+  _actor: null,
+  get actor() { return this._actor; },
+  get _transport() { return this._client._transport; },
+
+  /**
+   * Remove the breakpoint from the server.
+   */
+  remove: DebuggerClient.requester({
+    type: "delete"
+  }),
+
+  /**
+   * Determines if this breakpoint has a condition
+   */
+  hasCondition: function () {
+    let root = this._client.mainRoot;
+    // XXX bug 990137: We will remove support for client-side handling of
+    // conditional breakpoints
+    if (root.traits.conditionalBreakpoints) {
+      return "condition" in this;
+    } else {
+      return "conditionalExpression" in this;
+    }
+  },
+
+  /**
+   * Get the condition of this breakpoint. Currently we have to
+   * support locally emulated conditional breakpoints until the
+   * debugger servers are updated (see bug 990137). We used a
+   * different property when moving it server-side to ensure that we
+   * are testing the right code.
+   */
+  getCondition: function () {
+    let root = this._client.mainRoot;
+    if (root.traits.conditionalBreakpoints) {
+      return this.condition;
+    } else {
+      return this.conditionalExpression;
+    }
+  },
+
+  /**
+   * Set the condition of this breakpoint
+   */
+  setCondition: function (gThreadClient, aCondition) {
+    let root = this._client.mainRoot;
+    let deferred = promise.defer();
+
+    if (root.traits.conditionalBreakpoints) {
+      let info = {
+        line: this.location.line,
+        column: this.location.column,
+        condition: aCondition
+      };
+
+      // Remove the current breakpoint and add a new one with the
+      // condition.
+      this.remove(aResponse => {
+        if (aResponse && aResponse.error) {
+          deferred.reject(aResponse);
+          return;
+        }
+
+        this.source.setBreakpoint(info, (aResponse, aNewBreakpoint) => {
+          if (aResponse && aResponse.error) {
+            deferred.reject(aResponse);
+          } else {
+            deferred.resolve(aNewBreakpoint);
+          }
+        });
+      });
+    } else {
+      // The property shouldn't even exist if the condition is blank
+      if (aCondition === "") {
+        delete this.conditionalExpression;
+      }
+      else {
+        this.conditionalExpression = aCondition;
+      }
+      deferred.resolve(this);
+    }
+
+    return deferred.promise;
+  }
+};
+
+eventSource(BreakpointClient.prototype);
+
+/**
+ * Environment clients are used to manipulate the lexical environment actors.
+ *
+ * @param aClient DebuggerClient
+ *        The debugger client parent.
+ * @param aForm Object
+ *        The form sent across the remote debugging protocol.
+ */
+function EnvironmentClient(aClient, aForm) {
+  this._client = aClient;
+  this._form = aForm;
+  this.request = this._client.request;
+}
+exports.EnvironmentClient = EnvironmentClient;
+
+EnvironmentClient.prototype = {
+
+  get actor() {
+    return this._form.actor;
+  },
+  get _transport() { return this._client._transport; },
+
+  /**
+   * Fetches the bindings introduced by this lexical environment.
+   */
+  getBindings: DebuggerClient.requester({
+    type: "bindings"
+  }),
+
+  /**
+   * Changes the value of the identifier whose name is name (a string) to that
+   * represented by value (a grip).
+   */
+  assign: DebuggerClient.requester({
+    type: "assign",
+    name: args(0),
+    value: args(1)
+  })
+};
+
+eventSource(EnvironmentClient.prototype);
diff --git a/devtools/shared/client/moz.build b/devtools/shared/client/moz.build
new file mode 100644
index 000000000..aba5a2bfe
--- /dev/null
+++ b/devtools/shared/client/moz.build
@@ -0,0 +1,10 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+DevToolsModules(
+    'connection-manager.js',
+    'main.js',
+)