--- a/.eslintignore
+++ b/.eslintignore
@@ -224,20 +224,16 @@ dom/notification/test/unit/**
 dom/notification/test/mochitest/**
 dom/offline/**
 dom/payments/**
 dom/performance/**
 dom/permission/**
 dom/plugins/test/mochitest/**
 dom/plugins/test/unit/**
 dom/power/**
-dom/presentation/Presentation*.js
-dom/presentation/provider/**
-dom/presentation/tests/mochitest/**
-dom/presentation/tests/xpcshell/**
 dom/promise/**
 dom/push/**
 dom/quota/**
 dom/res/**
 dom/secureelement/**
 dom/security/test/contentverifier/**
 dom/security/test/cors/**
 dom/security/test/csp/**

--- a/dom/presentation/provider/AndroidCastDeviceProvider.js
+++ b/dom/presentation/provider/AndroidCastDeviceProvider.js
@@ -1,22 +1,17 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=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/. */
-/* jshint esnext:true, globalstrict:true, moz:true, undef:true, unused:true */
-/* globals Components, dump */
 "use strict";
 
-// globals XPCOMUtils
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
-// globals Services
 ChromeUtils.import("resource://gre/modules/Services.jsm");
-// globals EventDispatcher
 ChromeUtils.import("resource://gre/modules/Messaging.jsm");
 
 function log(str) {
   // dump("-*- AndroidCastDeviceProvider -*-: " + str + "\n");
 }
 
 // Helper function: transfer nsIPresentationChannelDescription to json
 function descriptionToString(aDescription) {
@@ -323,19 +318,17 @@ ChromecastRemoteDisplayDevice.prototype 
     // Disconnect from Chromecast.
     EventDispatcher.instance.sendRequestForResult({
       type: TOPIC_ANDROID_CAST_DEVICE_STOP,
       id:   this.id
     });
   },
 
   isRequestedUrlSupported: function CRDD_isRequestedUrlSupported(aUrl) {
-    let url = Cc["@mozilla.org/network/io-service;1"]
-                .getService(Ci.nsIIOService)
-                .newURI(aUrl);
+    let url = Services.io.newURI(aUrl);
     return url.scheme == "http" || url.scheme == "https";
   },
 
   // nsIPresentationLocalDevice
   get windowId() { return this._id; },
 
   // nsIObserver
   observe: function CRDD_observe(aSubject, aTopic, aData) {

--- a/dom/presentation/provider/PresentationControlService.js
+++ b/dom/presentation/provider/PresentationControlService.js
@@ -1,29 +1,21 @@
 /* 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/. */
-/* jshint esnext:true, globalstrict:true, moz:true, undef:true, unused:true */
-/* globals Components, dump */
 "use strict";
 
-/* globals XPCOMUtils */
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
-/* globals Services */
 ChromeUtils.import("resource://gre/modules/Services.jsm");
-/* globals NetUtil */
 ChromeUtils.import("resource://gre/modules/NetUtil.jsm");
-/* globals setTimeout, clearTimeout */
 ChromeUtils.import("resource://gre/modules/Timer.jsm");
 
-/* globals ControllerStateMachine */
-ChromeUtils.defineModuleGetter(this, "ControllerStateMachine", // jshint ignore:line
+ChromeUtils.defineModuleGetter(this, "ControllerStateMachine",
                                "resource://gre/modules/presentation/ControllerStateMachine.jsm");
-/* global ReceiverStateMachine */
-ChromeUtils.defineModuleGetter(this, "ReceiverStateMachine", // jshint ignore:line
+ChromeUtils.defineModuleGetter(this, "ReceiverStateMachine",
                                "resource://gre/modules/presentation/ReceiverStateMachine.jsm");
 
 const kProtocolVersion = 1; // need to review isCompatibleServer while fiddling the version number.
 const kLocalCertName = "presentation";
 
 const DEBUG = Services.prefs.getBoolPref("dom.presentation.tcp_server.debug");
 function log(aMsg) {
   dump("-*- PresentationControlService.js: " + aMsg + "\n");
@@ -854,17 +846,17 @@ TCPControlChannel.prototype = {
       }, kDisconnectTimeout);
     }
   },
 
   reconnect(aPresentationId, aUrl) {
     DEBUG && log("TCPControlChannel - reconnect with role: " +
                  this._direction); // jshint ignore:line
     if (this._direction != "sender") {
-      return Cr.NS_ERROR_FAILURE;
+      throw Cr.NS_ERROR_FAILURE;
     }
 
     this._stateMachine.reconnect(aPresentationId, aUrl);
   },
 
   // callback from state machine
   sendCommand(command) {
     this._outgoingMsgs.push(command);

new file mode 100644
--- /dev/null
+++ b/dom/presentation/tests/mochitest/.eslintrc.js
@@ -0,0 +1,7 @@
+"use strict";
+
+module.exports = {
+  "extends": [
+    "plugin:mozilla/mochitest-test"
+  ]
+};

--- a/dom/presentation/tests/mochitest/PresentationDeviceInfoChromeScript.js
+++ b/dom/presentation/tests/mochitest/PresentationDeviceInfoChromeScript.js
@@ -1,14 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
-const { XPCOMUtils } = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
+/* eslint-env mozilla/frame-script */
+
+const { XPCOMUtils } = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm", {});
 
 const manager = Cc["@mozilla.org/presentation-device/manager;1"]
                   .getService(Ci.nsIPresentationDeviceManager);
 
 var testProvider = {
   QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceProvider]),
   forceDiscovery() {
     sendAsyncMessage("force-discovery");

--- a/dom/presentation/tests/mochitest/PresentationSessionChromeScript.js
+++ b/dom/presentation/tests/mochitest/PresentationSessionChromeScript.js
@@ -1,13 +1,15 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
+/* eslint-env mozilla/frame-script */
+
 const Cm = Components.manager;
 
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 ChromeUtils.import("resource://gre/modules/Services.jsm");
 ChromeUtils.import("resource://gre/modules/Timer.jsm");
 
 const uuidGenerator = Cc["@mozilla.org/uuid-generator;1"]
                       .getService(Ci.nsIUUIDGenerator);
@@ -119,21 +121,21 @@ const mockedControlChannel = {
     if (answer.type == Ci.nsIPresentationChannelDescription.TYPE_TCP) {
       this._listener.QueryInterface(Ci.nsIPresentationSessionTransportCallback).notifyTransportReady();
     }
   },
   _isValidSDP(aSDP) {
     var isValid = false;
     if (aSDP.type == Ci.nsIPresentationChannelDescription.TYPE_TCP) {
       try {
-        var addresses = aSDP.tcpAddress;
-        if (addresses.length > 0) {
-          for (var i = 0; i < addresses.length; i++) {
+        var sdpAddresses = aSDP.tcpAddress;
+        if (sdpAddresses.length > 0) {
+          for (var i = 0; i < sdpAddresses.length; i++) {
             // Ensure CString addresses are used. Otherwise, an error will be thrown.
-            addresses.queryElementAt(i, Ci.nsISupportsCString);
+            sdpAddresses.queryElementAt(i, Ci.nsISupportsCString);
           }
 
           isValid = true;
         }
       } catch (e) {
         isValid = false;
       }
     } else if (aSDP.type == Ci.nsIPresentationChannelDescription.TYPE_DATACHANNEL) {
@@ -250,21 +252,21 @@ const mockedSessionTransport = {
     setTimeout(() => {
       this.simulateTransportReady();
     }, 0);
   },
   buildTCPReceiverTransport(description, listener) {
     this._listener = listener;
     this._role = Ci.nsIPresentationService.ROLE_RECEIVER;
 
-    var addresses = description.QueryInterface(Ci.nsIPresentationChannelDescription).tcpAddress;
+    var tcpAddresses = description.QueryInterface(Ci.nsIPresentationChannelDescription).tcpAddress;
     this._selfAddress = {
       QueryInterface: ChromeUtils.generateQI([Ci.nsINetAddr]),
-      address: (addresses.length > 0) ?
-                addresses.queryElementAt(0, Ci.nsISupportsCString).data : "",
+      address: (tcpAddresses.length > 0) ?
+                tcpAddresses.queryElementAt(0, Ci.nsISupportsCString).data : "",
       port: description.QueryInterface(Ci.nsIPresentationChannelDescription).tcpPort,
     };
 
     setTimeout(() => {
       this._listener.onSessionTransport(this);
       this._listener = null;
     }, 0);
   },
@@ -459,15 +461,13 @@ addMessageListener("save-control-channel
   controlChannelListener = mockedControlChannel.listener;
 });
 
 addMessageListener("restore-control-channel-listener", function(message) {
   mockedControlChannel.listener = controlChannelListener;
   controlChannelListener = null;
 });
 
-var obs = Cc["@mozilla.org/observer-service;1"]
-          .getService(Ci.nsIObserverService);
-obs.addObserver(function observer(aSubject, aTopic, aData) {
-  obs.removeObserver(observer, aTopic);
+Services.obs.addObserver(function observer(aSubject, aTopic, aData) {
+  Services.obs.removeObserver(observer, aTopic);
 
   requestPromise = aSubject;
 }, "setup-request-promise");

--- a/dom/presentation/tests/mochitest/PresentationSessionChromeScript1UA.js
+++ b/dom/presentation/tests/mochitest/PresentationSessionChromeScript1UA.js
@@ -1,15 +1,17 @@
 /* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
 /* 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";
 
+/* eslint-env mozilla/frame-script */
+
 const Cm = Components.manager;
 
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 ChromeUtils.import("resource://gre/modules/Services.jsm");
 
 const uuidGenerator = Cc["@mozilla.org/uuid-generator;1"]
                       .getService(Ci.nsIUUIDGenerator);
 
@@ -246,18 +248,16 @@ function initMockAndListener() {
 
     return { contractId,
              mockClassId,
              mockFactory,
              originalClassId,
              originalFactory };
   }
   // Register mock factories.
-  const uuidGenerator = Cc["@mozilla.org/uuid-generator;1"]
-                        .getService(Ci.nsIUUIDGenerator);
   originalFactoryData.push(registerMockFactory("@mozilla.org/presentation-device/prompt;1",
                                                uuidGenerator.generateUUID(),
                                                mockDevicePrompt));
   originalFactoryData.push(registerMockFactory("@mozilla.org/presentation/requestuiglue;1",
                                                uuidGenerator.generateUUID(),
                                                mockRequestUIGlue));
 
   addMessageListener("trigger-device-add", function() {
@@ -321,20 +321,19 @@ function initMockAndListener() {
   // Used to call sendAsyncMessage in chrome script from receiver.
   addMessageListener("forward-command", function(command_data) {
     let command = JSON.parse(command_data);
     sendAsyncMessage(command.name, command.data);
   });
 
   addMessageListener("teardown", teardown);
 
-  var obs = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService);
-  obs.addObserver(function setupRequestPromiseHandler(aSubject, aTopic, aData) {
+  Services.obs.addObserver(function setupRequestPromiseHandler(aSubject, aTopic, aData) {
     debug("Got observer: setup-request-promise");
-    obs.removeObserver(setupRequestPromiseHandler, aTopic);
+    Services.obs.removeObserver(setupRequestPromiseHandler, aTopic);
     mockRequestUIGlue.promise = aSubject;
     sendAsyncMessage("promise-setup-ready");
   }, "setup-request-promise");
 }
 
 function teardown() {
 
   function registerOriginalFactory(contractId, mockedClassId, mockedFactory, originalClassId, originalFactory) {

--- a/dom/presentation/tests/mochitest/PresentationSessionFrameScript.js
+++ b/dom/presentation/tests/mochitest/PresentationSessionFrameScript.js
@@ -1,12 +1,14 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
+/* eslint-env mozilla/frame-script */
+
 function loadPrivilegedScriptTest() {
   /**
    * The script is loaded as
    * (a) a privileged script in content process for dc_sender.html
    * (b) a frame script in the remote iframe process for dc_receiver_oop.html
    * |type port == "undefined"| indicates the script is load by
    * |loadPrivilegedScript| which is the first case.
    */
@@ -29,46 +31,50 @@ function loadPrivilegedScriptTest() {
       var type = e.data.type;
       if (!handlers.hasOwnProperty(type)) {
         return;
       }
       var args = [e];
       handlers[type].forEach(handler => handler.apply(null, args));
     };
     var handlers = {};
+    /* eslint-disable-next-line no-native-reassign */
     addMessageListener = function(message, handler) {
       if (handlers.hasOwnProperty(message)) {
         handlers[message].push(handler);
       } else {
         handlers[message] = [handler];
       }
     };
+    /* eslint-disable-next-line no-native-reassign */
     removeMessageListener = function(message, handler) {
       if (!handler || !handlers.hasOwnProperty(message)) {
         return;
       }
       var index = handlers[message].indexOf(handler);
       if (index != -1) {
         handlers[message].splice(index, 1);
       }
     };
   }
 
   const Cm = Components.manager;
 
   const mockedChannelDescription = {
+    /* eslint-disable-next-line mozilla/use-chromeutils-generateqi */
     QueryInterface(iid) {
       const interfaces = [Ci.nsIPresentationChannelDescription];
 
       if (!interfaces.some(v => iid.equals(v))) {
           throw Cr.NS_ERROR_NO_INTERFACE;
       }
       return this;
     },
     get type() {
+      /* global Services */
       if (Services.prefs.getBoolPref("dom.presentation.session_transport.data_channel.enable")) {
         return Ci.nsIPresentationChannelDescription.TYPE_DATACHANNEL;
       }
       return Ci.nsIPresentationChannelDescription.TYPE_TCP;
     },
     get dataChannelSDP() {
       return "test-sdp";
     }
@@ -78,16 +84,17 @@ function loadPrivilegedScriptTest() {
     let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
     timer.initWithCallback({ notify: callback },
                            delay,
                            Ci.nsITimer.TYPE_ONE_SHOT);
     return timer;
   }
 
   const mockedSessionTransport = {
+    /* eslint-disable-next-line mozilla/use-chromeutils-generateqi */
     QueryInterface(iid) {
         const interfaces = [Ci.nsIPresentationSessionTransport,
                             Ci.nsIPresentationDataChannelSessionTransportBuilder,
                             Ci.nsIFactory];
 
         if (!interfaces.some(v => iid.equals(v))) {
             throw Cr.NS_ERROR_NO_INTERFACE;
         }

--- a/dom/presentation/tests/mochitest/file_presentation_non_receiver_inner_iframe.html
+++ b/dom/presentation/tests/mochitest/file_presentation_non_receiver_inner_iframe.html
@@ -5,18 +5,18 @@
   <title>Test for B2G PresentationReceiver on a non-receiver inner iframe of the receiver page at receiver side</title>
 </head>
 <body onload="testConnectionAvailable()">
 <div id="content"></div>
 <script type="application/javascript">
 
 "use strict";
 
-function ok(a, msg) {
-  alert((a ? "OK " : "KO ") + msg);
+function is(a, b, msg) {
+  alert((a === b ? "OK " : "KO ") + msg);
 }
 
 function testConnectionAvailable() {
   return new Promise(function(aResolve, aReject) {
     is(navigator.presentation.receiver, null, "navigator.presentation.receiver shouldn't be available in inner iframes with different origins from receiving pages.");
     aResolve();
   });
 }

--- a/dom/presentation/tests/mochitest/file_presentation_receiver.html
+++ b/dom/presentation/tests/mochitest/file_presentation_receiver.html
@@ -80,17 +80,17 @@ function testConnectionUnavailableDiffOr
 
     aResolve();
   });
 }
 
 function testConnectionListSameObject() {
   return new Promise(function(aResolve, aReject) {
     is(navigator.presentation.receiver.connectionList, navigator.presentation.receiver.connectionList, "The promise should be the same object.");
-    var promise = navigator.presentation.receiver.connectionList.then(
+    navigator.presentation.receiver.connectionList.then(
       function(aList) {
         is(connection, aList.connections[0], "The connection from list and the one from |connectionavailable| event should be the same.");
         aResolve();
       },
       function(aError) {
         ok(false, "Error occurred when getting the connection list: " + aError);
         finish();
         aReject();

--- a/dom/presentation/tests/mochitest/file_presentation_reconnect.html
+++ b/dom/presentation/tests/mochitest/file_presentation_reconnect.html
@@ -50,17 +50,16 @@ function testStartRequest() {
         connection.onconnect = function() {
           connection.onconnect = null;
           is(connection.state, "connected", "Connection should be connected.");
           aResolve();
         };
       },
       function(aError) {
         ok(false, "Error occurred when establishing a connection: " + aError);
-        teardown();
         aReject();
       }
     );
   });
 }
 
 function testCloseConnection() {
   return new Promise(function(aResolve, aReject) {

--- a/dom/presentation/tests/mochitest/test_presentation_1ua_connection_wentaway.js
+++ b/dom/presentation/tests/mochitest/test_presentation_1ua_connection_wentaway.js
@@ -60,18 +60,17 @@ function setup() {
       }
     });
 
     var promise = new Promise(function(aResolve, aReject) {
       document.body.appendChild(receiverIframe);
       aResolve(receiverIframe);
     });
 
-    var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-                           .getService(SpecialPowers.Ci.nsIObserverService);
+    var obs = SpecialPowers.Services.obs;
     obs.notifyObservers(promise, "setup-request-promise");
   });
 
   gScript.addMessageListener("promise-setup-ready", function promiseSetupReadyHandler() {
     debug("Got message: promise-setup-ready");
     gScript.removeMessageListener("promise-setup-ready",
                                   promiseSetupReadyHandler);
     gScript.sendAsyncMessage("trigger-on-session-request", receiverUrl);

--- a/dom/presentation/tests/mochitest/test_presentation_1ua_sender_and_receiver.js
+++ b/dom/presentation/tests/mochitest/test_presentation_1ua_sender_and_receiver.js
@@ -69,18 +69,17 @@ function setup() {
       }
     });
 
     var promise = new Promise(function(aResolve, aReject) {
       document.body.appendChild(receiverIframe);
       aResolve(receiverIframe);
     });
 
-    var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-                           .getService(SpecialPowers.Ci.nsIObserverService);
+    var obs = SpecialPowers.Services.obs;
     obs.notifyObservers(promise, "setup-request-promise");
   });
 
   gScript.addMessageListener("promise-setup-ready", function promiseSetupReadyHandler() {
     debug("Got message: promise-setup-ready");
     gScript.removeMessageListener("promise-setup-ready", promiseSetupReadyHandler);
     gScript.sendAsyncMessage("trigger-on-session-request", receiverUrl);
   });

--- a/dom/presentation/tests/mochitest/test_presentation_availability_iframe.html
+++ b/dom/presentation/tests/mochitest/test_presentation_availability_iframe.html
@@ -82,36 +82,36 @@ function testOnChangeEvent() {
       is(availability.value, false, "Should have no available device after device removed");
       aResolve();
     };
     gScript.sendAsyncMessage("trigger-device-remove");
   });
 }
 
 function testConsecutiveGetAvailability() {
-  let request = new PresentationRequest("https://example.org");
+  let presRequest = new PresentationRequest("https://example.org");
   let firstAvailabilityResolved = false;
   return Promise.all([
-    request.getAvailability().then(function() {
+    presRequest.getAvailability().then(function() {
       firstAvailabilityResolved = true;
     }),
-    request.getAvailability().then(function() {
+    presRequest.getAvailability().then(function() {
       ok(firstAvailabilityResolved, "getAvailability() should be resolved in sequence");
     })
   ]).catch(function(aError) {
     ok(false, "Error occurred when getting availability: " + aError);
     teardown();
   });
 }
 
 function testUnsupportedDeviceAvailability() {
   return Promise.race([
     new Promise(function(aResolve, aReject) {
-      let request = new PresentationRequest("https://test.com");
-      request.getAvailability().then(function(aAvailability) {
+      let presRequest = new PresentationRequest("https://test.com");
+      presRequest.getAvailability().then(function(aAvailability) {
         availability = aAvailability;
         aAvailability.onchange = function() {
           availability.onchange = null;
           ok(false, "Should not get onchange event.");
           teardown();
         };
       });
       gScript.sendAsyncMessage("trigger-add-unsupport-url-device");

--- a/dom/presentation/tests/mochitest/test_presentation_datachannel_sessiontransport.html
+++ b/dom/presentation/tests/mochitest/test_presentation_datachannel_sessiontransport.html
@@ -25,18 +25,18 @@ const loadingTimeoutPref = "presentation
 var clientBuilder;
 var serverBuilder;
 var clientTransport;
 var serverTransport;
 
 const clientMessage = "Client Message";
 const serverMessage = "Server Message";
 
-const { XPCOMUtils } = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
-const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+const { XPCOMUtils } = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm", {});
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm", {});
 
 var isClientReady = false;
 var isServerReady = false;
 var isClientClosed = false;
 var isServerClosed = false;
 
 var gResolve;
 var gReject;

--- a/dom/presentation/tests/mochitest/test_presentation_dc_receiver.html
+++ b/dom/presentation/tests/mochitest/test_presentation_dc_receiver.html
@@ -15,18 +15,17 @@
 <pre id="test"></pre>
 <script type="application/javascript">
 
 "use strict";
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 var receiverUrl = SimpleTest.getTestFileURL("file_presentation_receiver.html");
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 
 function setup() {
   return new Promise(function(aResolve, aReject) {
     gScript.sendAsyncMessage("trigger-device-add");
 
     var iframe = document.createElement("iframe");
     iframe.setAttribute("src", receiverUrl);
     iframe.setAttribute("mozbrowser", "true");
@@ -46,20 +45,20 @@ function setup() {
         gScript.sendAsyncMessage(command.name, command.data);
       } else if (/^DONE$/.exec(message)) {
         iframe.removeEventListener("mozbrowsershowmodalprompt",
                                    receiverListener);
         teardown();
       }
     });
 
-    var promise = new Promise(function(aResolve, aReject) {
+    var promise = new Promise(function(aInnerResolve, aInnerReject) {
       document.body.appendChild(iframe);
 
-      aResolve(iframe);
+      aInnerResolve(iframe);
     });
     obs.notifyObservers(promise, "setup-request-promise");
 
     gScript.addMessageListener("offer-received", function offerReceivedHandler() {
       gScript.removeMessageListener("offer-received", offerReceivedHandler);
       info("An offer is received.");
     });
 

--- a/dom/presentation/tests/mochitest/test_presentation_dc_receiver_oop.html
+++ b/dom/presentation/tests/mochitest/test_presentation_dc_receiver_oop.html
@@ -20,18 +20,17 @@
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 var receiverUrl = SimpleTest.getTestFileURL("file_presentation_receiver.html");
 var nonReceiverUrl = SimpleTest.getTestFileURL("file_presentation_non_receiver.html");
 
 var isReceiverFinished = false;
 var isNonReceiverFinished = false;
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 var receiverIframe;
 
 function setup() {
   return new Promise(function(aResolve, aReject) {
     gScript.sendAsyncMessage("trigger-device-add");
 
     // Create a receiver OOP iframe.
     receiverIframe = document.createElement("iframe");
@@ -64,24 +63,24 @@ function setup() {
         isReceiverFinished = true;
 
         if (isNonReceiverFinished) {
           teardown();
         }
       }
     });
 
-    var promise = new Promise(function(aResolve, aReject) {
+    var promise = new Promise(function(aInnerResolve, aInnerReject) {
       document.body.appendChild(receiverIframe);
       receiverIframe.addEventListener("mozbrowserloadstart", function() {
         var mm = SpecialPowers.getBrowserFrameMessageManager(receiverIframe);
         mm.loadFrameScript("data:,(" + loadPrivilegedScriptTest.toString() + ")();", false);
       }, {once: true});
 
-      aResolve(receiverIframe);
+      aInnerResolve(receiverIframe);
     });
     obs.notifyObservers(promise, "setup-request-promise");
 
     // Create a non-receiver OOP iframe.
     var nonReceiverIframe = document.createElement("iframe");
     nonReceiverIframe.setAttribute("remote", "true");
     nonReceiverIframe.setAttribute("mozbrowser", "true");
     nonReceiverIframe.setAttribute("src", nonReceiverUrl);

--- a/dom/presentation/tests/mochitest/test_presentation_fingerprinting_resistance.html
+++ b/dom/presentation/tests/mochitest/test_presentation_fingerprinting_resistance.html
@@ -73,22 +73,22 @@ let testRequestAndReceiver = (request) =
     iframe.setAttribute("mozbrowser", "true");
     iframe.setAttribute("mozpresentation", kReceiverUrl);
     iframe.setAttribute("remote", "false");
     iframe.addEventListener("mozbrowsershowmodalprompt", (event) => {
       SimpleTest.is(event.detail.message, "true", "navigator.presentation.receiver");
       resolve(iframe);
     }, {once: true});
 
-    let promise = new Promise((resolve) => {
+    let promise = new Promise((aInnerResolve) => {
       document.body.appendChild(iframe);
-      resolve(iframe);
+      aInnerResolve(iframe);
     });
 
-    let obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"].getService(SpecialPowers.Ci.nsIObserverService);
+    let obs = SpecialPowers.Services.obs;
     obs.notifyObservers(promise, "setup-request-promise");
   });
 
   request.start().then((connection) => {
     SimpleTest.ok(connection, "PresentationRequest.start");
   }).catch((error) => {
     SimpleTest.ok(false, "PresentationRequest.start: " + error);
     teardown();

--- a/dom/presentation/tests/mochitest/test_presentation_receiver_auxiliary_navigation.js
+++ b/dom/presentation/tests/mochitest/test_presentation_receiver_auxiliary_navigation.js
@@ -1,70 +1,65 @@
 "use strict";
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 var receiverUrl = SimpleTest.getTestFileURL("file_presentation_receiver_auxiliary_navigation.html");
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 
 function setup() {
-  return new Promise(function(aResolve, aReject) {
-    gScript.sendAsyncMessage("trigger-device-add");
+  gScript.sendAsyncMessage("trigger-device-add");
 
-    var iframe = document.createElement("iframe");
-    iframe.setAttribute("mozbrowser", "true");
-    iframe.setAttribute("mozpresentation", receiverUrl);
-    var oop = !location.pathname.includes("_inproc");
-    iframe.setAttribute("remote", oop);
-    iframe.setAttribute("src", receiverUrl);
+  var iframe = document.createElement("iframe");
+  iframe.setAttribute("mozbrowser", "true");
+  iframe.setAttribute("mozpresentation", receiverUrl);
+  var oop = !location.pathname.includes("_inproc");
+  iframe.setAttribute("remote", oop);
+  iframe.setAttribute("src", receiverUrl);
 
-    // This event is triggered when the iframe calls "postMessage".
-    iframe.addEventListener("mozbrowsershowmodalprompt", function listener(aEvent) {
-      var message = aEvent.detail.message;
-      if (/^OK /.exec(message)) {
-        ok(true, "Message from iframe: " + message);
-      } else if (/^KO /.exec(message)) {
-        ok(false, "Message from iframe: " + message);
-      } else if (/^INFO /.exec(message)) {
-        info("Message from iframe: " + message);
-      } else if (/^COMMAND /.exec(message)) {
-        var command = JSON.parse(message.replace(/^COMMAND /, ""));
-        gScript.sendAsyncMessage(command.name, command.data);
-      } else if (/^DONE$/.exec(message)) {
-        ok(true, "Messaging from iframe complete.");
-        iframe.removeEventListener("mozbrowsershowmodalprompt", listener);
+  // This event is triggered when the iframe calls "postMessage".
+  iframe.addEventListener("mozbrowsershowmodalprompt", function listener(aEvent) {
+    var message = aEvent.detail.message;
+    if (/^OK /.exec(message)) {
+      ok(true, "Message from iframe: " + message);
+    } else if (/^KO /.exec(message)) {
+      ok(false, "Message from iframe: " + message);
+    } else if (/^INFO /.exec(message)) {
+      info("Message from iframe: " + message);
+    } else if (/^COMMAND /.exec(message)) {
+      var command = JSON.parse(message.replace(/^COMMAND /, ""));
+      gScript.sendAsyncMessage(command.name, command.data);
+    } else if (/^DONE$/.exec(message)) {
+      ok(true, "Messaging from iframe complete.");
+      iframe.removeEventListener("mozbrowsershowmodalprompt", listener);
 
-        teardown();
-      }
-    });
-
-    var promise = new Promise(function(aResolve, aReject) {
-      document.body.appendChild(iframe);
+      teardown();
+    }
+  });
 
-      aResolve(iframe);
-    });
-    obs.notifyObservers(promise, "setup-request-promise");
+  var promise = new Promise(function(aResolve, aReject) {
+    document.body.appendChild(iframe);
 
-    aResolve();
+    aResolve(iframe);
   });
+  obs.notifyObservers(promise, "setup-request-promise");
 }
 
 function teardown() {
   gScript.addMessageListener("teardown-complete", function teardownCompleteHandler() {
     gScript.removeMessageListener("teardown-complete", teardownCompleteHandler);
     gScript.destroy();
     SimpleTest.finish();
   });
 
   gScript.sendAsyncMessage("teardown");
 }
 
 function runTests() {
-  setup().then();
+  setup();
 }
 
 SimpleTest.waitForExplicitFinish();
 SpecialPowers.pushPermissions([
   {type: "presentation-device-manage", allow: false, context: document},
   {type: "browser", allow: true, context: document},
 ], function() {
   SpecialPowers.pushPrefEnv({ "set": [["dom.presentation.enabled", true],

--- a/dom/presentation/tests/mochitest/test_presentation_tcp_receiver.html
+++ b/dom/presentation/tests/mochitest/test_presentation_tcp_receiver.html
@@ -15,81 +15,76 @@
 <pre id="test"></pre>
 <script type="application/javascript">
 
 "use strict";
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 var receiverUrl = SimpleTest.getTestFileURL("file_presentation_receiver.html");
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 
 function setup() {
-  return new Promise(function(aResolve, aReject) {
-    gScript.sendAsyncMessage("trigger-device-add");
+  gScript.sendAsyncMessage("trigger-device-add");
 
-    var iframe = document.createElement("iframe");
-    iframe.setAttribute("mozbrowser", "true");
-    iframe.setAttribute("mozpresentation", receiverUrl);
-    iframe.setAttribute("src", receiverUrl);
+  var iframe = document.createElement("iframe");
+  iframe.setAttribute("mozbrowser", "true");
+  iframe.setAttribute("mozpresentation", receiverUrl);
+  iframe.setAttribute("src", receiverUrl);
 
-    // This event is triggered when the iframe calls "postMessage".
-    iframe.addEventListener("mozbrowsershowmodalprompt", function listener(aEvent) {
-      var message = aEvent.detail.message;
-      if (/^OK /.exec(message)) {
-        ok(true, "Message from iframe: " + message);
-      } else if (/^KO /.exec(message)) {
-        ok(false, "Message from iframe: " + message);
-      } else if (/^INFO /.exec(message)) {
-        info("Message from iframe: " + message);
-      } else if (/^COMMAND /.exec(message)) {
-        var command = JSON.parse(message.replace(/^COMMAND /, ""));
-        gScript.sendAsyncMessage(command.name, command.data);
-      } else if (/^DONE$/.exec(message)) {
-        ok(true, "Messaging from iframe complete.");
-        iframe.removeEventListener("mozbrowsershowmodalprompt", listener);
+  // This event is triggered when the iframe calls "postMessage".
+  iframe.addEventListener("mozbrowsershowmodalprompt", function listener(aEvent) {
+    var message = aEvent.detail.message;
+    if (/^OK /.exec(message)) {
+      ok(true, "Message from iframe: " + message);
+    } else if (/^KO /.exec(message)) {
+      ok(false, "Message from iframe: " + message);
+    } else if (/^INFO /.exec(message)) {
+      info("Message from iframe: " + message);
+    } else if (/^COMMAND /.exec(message)) {
+      var command = JSON.parse(message.replace(/^COMMAND /, ""));
+      gScript.sendAsyncMessage(command.name, command.data);
+    } else if (/^DONE$/.exec(message)) {
+      ok(true, "Messaging from iframe complete.");
+      iframe.removeEventListener("mozbrowsershowmodalprompt", listener);
 
-        teardown();
-      }
-    });
-
-    var promise = new Promise(function(aResolve, aReject) {
-      document.body.appendChild(iframe);
+      teardown();
+    }
+  });
 
-      aResolve(iframe);
-    });
-    obs.notifyObservers(promise, "setup-request-promise");
+  var promise = new Promise(function(aResolve, aReject) {
+    document.body.appendChild(iframe);
 
-    gScript.addMessageListener("offer-received", function offerReceivedHandler() {
-      gScript.removeMessageListener("offer-received", offerReceivedHandler);
-      info("An offer is received.");
-    });
+    aResolve(iframe);
+  });
+  obs.notifyObservers(promise, "setup-request-promise");
 
-    gScript.addMessageListener("answer-sent", function answerSentHandler(aIsValid) {
-      gScript.removeMessageListener("answer-sent", answerSentHandler);
-      ok(aIsValid, "A valid answer is sent.");
-    });
+  gScript.addMessageListener("offer-received", function offerReceivedHandler() {
+    gScript.removeMessageListener("offer-received", offerReceivedHandler);
+    info("An offer is received.");
+  });
 
-    gScript.addMessageListener("control-channel-closed", function controlChannelClosedHandler(aReason) {
-      gScript.removeMessageListener("control-channel-closed", controlChannelClosedHandler);
-      is(aReason, SpecialPowers.Cr.NS_OK, "The control channel is closed normally.");
-    });
+  gScript.addMessageListener("answer-sent", function answerSentHandler(aIsValid) {
+    gScript.removeMessageListener("answer-sent", answerSentHandler);
+    ok(aIsValid, "A valid answer is sent.");
+  });
 
-    gScript.addMessageListener("data-transport-notification-enabled", function dataTransportNotificationEnabledHandler() {
-      gScript.removeMessageListener("data-transport-notification-enabled", dataTransportNotificationEnabledHandler);
-      info("Data notification is enabled for data transport channel.");
-    });
+  gScript.addMessageListener("control-channel-closed", function controlChannelClosedHandler(aReason) {
+    gScript.removeMessageListener("control-channel-closed", controlChannelClosedHandler);
+    is(aReason, SpecialPowers.Cr.NS_OK, "The control channel is closed normally.");
+  });
 
-    gScript.addMessageListener("data-transport-closed", function dataTransportClosedHandler(aReason) {
-      gScript.removeMessageListener("data-transport-closed", dataTransportClosedHandler);
-      is(aReason, SpecialPowers.Cr.NS_OK, "The data transport should be closed normally.");
-    });
+  gScript.addMessageListener("data-transport-notification-enabled", function dataTransportNotificationEnabledHandler() {
+    gScript.removeMessageListener("data-transport-notification-enabled", dataTransportNotificationEnabledHandler);
+    info("Data notification is enabled for data transport channel.");
+  });
 
-    aResolve();
+  gScript.addMessageListener("data-transport-closed", function dataTransportClosedHandler(aReason) {
+    gScript.removeMessageListener("data-transport-closed", dataTransportClosedHandler);
+    is(aReason, SpecialPowers.Cr.NS_OK, "The data transport should be closed normally.");
   });
 }
 
 function testIncomingSessionRequest() {
   return new Promise(function(aResolve, aReject) {
     gScript.addMessageListener("receiver-launching", function launchReceiverHandler(aSessionId) {
       gScript.removeMessageListener("receiver-launching", launchReceiverHandler);
       info("Trying to launch receiver page.");
@@ -109,18 +104,18 @@ function teardown() {
     gScript.destroy();
     SimpleTest.finish();
   });
 
   gScript.sendAsyncMessage("teardown");
 }
 
 function runTests() {
-  setup().
-  then(testIncomingSessionRequest);
+  setup();
+  testIncomingSessionRequest();
 }
 
 SimpleTest.waitForExplicitFinish();
 SpecialPowers.pushPermissions([
   {type: "presentation-device-manage", allow: false, context: document},
   {type: "browser", allow: true, context: document},
 ], function() {
   SpecialPowers.pushPrefEnv({ "set": [["dom.presentation.enabled", true],

--- a/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_establish_connection_error.html
+++ b/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_establish_connection_error.html
@@ -12,60 +12,55 @@
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1069230">Test for connection establishing errors of B2G Presentation API at receiver side</a>
 <script type="application/javascript">
 
 "use strict";
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 var receiverUrl = SimpleTest.getTestFileURL("file_presentation_receiver_establish_connection_error.html");
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 
 function setup() {
-  return new Promise(function(aResolve, aReject) {
-    gScript.sendAsyncMessage("trigger-device-add");
+  gScript.sendAsyncMessage("trigger-device-add");
 
-    var iframe = document.createElement("iframe");
-    iframe.setAttribute("src", receiverUrl);
-    iframe.setAttribute("mozbrowser", "true");
-    iframe.setAttribute("mozpresentation", receiverUrl);
+  var iframe = document.createElement("iframe");
+  iframe.setAttribute("src", receiverUrl);
+  iframe.setAttribute("mozbrowser", "true");
+  iframe.setAttribute("mozpresentation", receiverUrl);
 
-    // This event is triggered when the iframe calls "alert".
-    iframe.addEventListener("mozbrowsershowmodalprompt", function receiverListener(evt) {
-      var message = evt.detail.message;
-      if (/^OK /.exec(message)) {
-        ok(true, message.replace(/^OK /, ""));
-      } else if (/^KO /.exec(message)) {
-        ok(false, message.replace(/^KO /, ""));
-      } else if (/^INFO /.exec(message)) {
-        info(message.replace(/^INFO /, ""));
-      } else if (/^COMMAND /.exec(message)) {
-        var command = JSON.parse(message.replace(/^COMMAND /, ""));
-        gScript.sendAsyncMessage(command.name, command.data);
-      } else if (/^DONE$/.exec(message)) {
-        iframe.removeEventListener("mozbrowsershowmodalprompt",
-                                   receiverListener);
-        teardown();
-      }
-    });
+  // This event is triggered when the iframe calls "alert".
+  iframe.addEventListener("mozbrowsershowmodalprompt", function receiverListener(evt) {
+    var message = evt.detail.message;
+    if (/^OK /.exec(message)) {
+      ok(true, message.replace(/^OK /, ""));
+    } else if (/^KO /.exec(message)) {
+      ok(false, message.replace(/^KO /, ""));
+    } else if (/^INFO /.exec(message)) {
+      info(message.replace(/^INFO /, ""));
+    } else if (/^COMMAND /.exec(message)) {
+      var command = JSON.parse(message.replace(/^COMMAND /, ""));
+      gScript.sendAsyncMessage(command.name, command.data);
+    } else if (/^DONE$/.exec(message)) {
+      iframe.removeEventListener("mozbrowsershowmodalprompt",
+                                 receiverListener);
+      teardown();
+    }
+  });
 
-    var promise = new Promise(function(aResolve, aReject) {
-      document.body.appendChild(iframe);
-
-      aResolve(iframe);
-    });
-    obs.notifyObservers(promise, "setup-request-promise");
+  var promise = new Promise(function(aResolve, aReject) {
+    document.body.appendChild(iframe);
 
-    gScript.addMessageListener("control-channel-closed", function controlChannelClosedHandler(aReason) {
-      gScript.removeMessageListener("control-channel-closed", controlChannelClosedHandler);
-      is(aReason, 0x80004004 /* NS_ERROR_ABORT */, "The control channel is closed abnormally.");
-    });
+    aResolve(iframe);
+  });
+  obs.notifyObservers(promise, "setup-request-promise");
 
-    aResolve();
+  gScript.addMessageListener("control-channel-closed", function controlChannelClosedHandler(aReason) {
+    gScript.removeMessageListener("control-channel-closed", controlChannelClosedHandler);
+    is(aReason, 0x80004004 /* NS_ERROR_ABORT */, "The control channel is closed abnormally.");
   });
 }
 
 function testIncomingSessionRequest() {
   return new Promise(function(aResolve, aReject) {
     gScript.addMessageListener("receiver-launching", function launchReceiverHandler(aSessionId) {
       gScript.removeMessageListener("receiver-launching", launchReceiverHandler);
       info("Trying to launch receiver page.");
@@ -83,18 +78,18 @@ function teardown() {
     gScript.destroy();
     SimpleTest.finish();
   });
 
   gScript.sendAsyncMessage("teardown");
 }
 
 function runTests() {
-  setup().
-  then(testIncomingSessionRequest);
+  setup();
+  testIncomingSessionRequest();
 }
 
 SimpleTest.waitForExplicitFinish();
 SpecialPowers.pushPermissions([
   {type: "presentation-device-manage", allow: false, context: document},
   {type: "browser", allow: true, context: document},
 ], function() {
   SpecialPowers.pushPrefEnv({ "set": [["dom.presentation.enabled", true],

--- a/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_establish_connection_timeout.html
+++ b/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_establish_connection_timeout.html
@@ -11,30 +11,25 @@
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1069230">Test for connection establishing timeout of B2G Presentation API at receiver side</a>
 <script type="application/javascript">
 
 "use strict";
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 
 function setup() {
-  return new Promise(function(aResolve, aReject) {
-    gScript.sendAsyncMessage("trigger-device-add");
+  gScript.sendAsyncMessage("trigger-device-add");
 
-    var promise = new Promise(function(aResolve, aReject) {
-      // In order to trigger timeout, do not resolve the promise.
-    });
-    obs.notifyObservers(promise, "setup-request-promise");
-
-    aResolve();
+  var promise = new Promise(function(aResolve, aReject) {
+    // In order to trigger timeout, do not resolve the promise.
   });
+  obs.notifyObservers(promise, "setup-request-promise");
 }
 
 function testIncomingSessionRequestReceiverLaunchTimeout() {
   return new Promise(function(aResolve, aReject) {
     gScript.addMessageListener("receiver-launching", function launchReceiverHandler(aSessionId) {
       gScript.removeMessageListener("receiver-launching", launchReceiverHandler);
       info("Trying to launch receiver page.");
     });
@@ -55,18 +50,18 @@ function teardown() {
     gScript.destroy();
     SimpleTest.finish();
   });
 
   gScript.sendAsyncMessage("teardown");
 }
 
 function runTests() {
-  setup().
-  then(testIncomingSessionRequestReceiverLaunchTimeout).
+  setup();
+  testIncomingSessionRequestReceiverLaunchTimeout().
   then(teardown);
 }
 
 SimpleTest.waitForExplicitFinish();
 SpecialPowers.pushPermissions([
   {type: "presentation-device-manage", allow: false, context: document},
 ], function() {
   SpecialPowers.pushPrefEnv({ "set": [["dom.presentation.enabled", true],

--- a/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_establish_connection_unknown_content_type.js
+++ b/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_establish_connection_unknown_content_type.js
@@ -1,38 +1,33 @@
 "use strict";
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 var receiverUrl = SimpleTest.getTestFileURL("file_presentation_unknown_content_type.test");
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 
 var receiverIframe;
 
 function setup() {
-  return new Promise(function(aResolve, aReject) {
-    gScript.sendAsyncMessage("trigger-device-add");
-
-    receiverIframe = document.createElement("iframe");
-    receiverIframe.setAttribute("mozbrowser", "true");
-    receiverIframe.setAttribute("mozpresentation", receiverUrl);
-    receiverIframe.setAttribute("src", receiverUrl);
-    var oop = !location.pathname.includes("_inproc");
-    receiverIframe.setAttribute("remote", oop);
+  gScript.sendAsyncMessage("trigger-device-add");
 
-    var promise = new Promise(function(aResolve, aReject) {
-      document.body.appendChild(receiverIframe);
+  receiverIframe = document.createElement("iframe");
+  receiverIframe.setAttribute("mozbrowser", "true");
+  receiverIframe.setAttribute("mozpresentation", receiverUrl);
+  receiverIframe.setAttribute("src", receiverUrl);
+  var oop = !location.pathname.includes("_inproc");
+  receiverIframe.setAttribute("remote", oop);
 
-      aResolve(receiverIframe);
-    });
-    obs.notifyObservers(promise, "setup-request-promise");
+  var promise = new Promise(function(aResolve, aReject) {
+    document.body.appendChild(receiverIframe);
 
-    aResolve();
+    aResolve(receiverIframe);
   });
+  obs.notifyObservers(promise, "setup-request-promise");
 }
 
 function testIncomingSessionRequestReceiverLaunchUnknownContentType() {
   let promise = Promise.all([
     new Promise(function(aResolve, aReject) {
       gScript.addMessageListener("receiver-launching", function launchReceiverHandler(aSessionId) {
         gScript.removeMessageListener("receiver-launching", launchReceiverHandler);
         info("Trying to launch receiver page.");
@@ -62,19 +57,19 @@ function teardown() {
     gScript.destroy();
     SimpleTest.finish();
   });
 
   gScript.sendAsyncMessage("teardown");
 }
 
 function runTests() {
-  setup().
-  then(testIncomingSessionRequestReceiverLaunchUnknownContentType).
-  then(teardown);
+  setup();
+
+  testIncomingSessionRequestReceiverLaunchUnknownContentType().then(teardown);
 }
 
 SimpleTest.waitForExplicitFinish();
 SpecialPowers.pushPermissions([
   {type: "presentation-device-manage", allow: false, context: document},
   {type: "browser", allow: true, context: document},
 ], function() {
   SpecialPowers.pushPrefEnv({ "set": [["dom.presentation.enabled", true],

--- a/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_oop.html
+++ b/dom/presentation/tests/mochitest/test_presentation_tcp_receiver_oop.html
@@ -19,119 +19,114 @@
 
 var gScript = SpecialPowers.loadChromeScript(SimpleTest.getTestFileURL("PresentationSessionChromeScript.js"));
 var receiverUrl = SimpleTest.getTestFileURL("file_presentation_receiver.html");
 var nonReceiverUrl = SimpleTest.getTestFileURL("file_presentation_non_receiver.html");
 
 var isReceiverFinished = false;
 var isNonReceiverFinished = false;
 
-var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-          .getService(SpecialPowers.Ci.nsIObserverService);
+var obs = SpecialPowers.Services.obs;
 
 function setup() {
-  return new Promise(function(aResolve, aReject) {
-    gScript.sendAsyncMessage("trigger-device-add");
+  gScript.sendAsyncMessage("trigger-device-add");
 
-    // Create a receiver OOP iframe.
-    var receiverIframe = document.createElement("iframe");
-    receiverIframe.setAttribute("remote", "true");
-    receiverIframe.setAttribute("mozbrowser", "true");
-    receiverIframe.setAttribute("mozpresentation", receiverUrl);
-    receiverIframe.setAttribute("src", receiverUrl);
+  // Create a receiver OOP iframe.
+  var receiverIframe = document.createElement("iframe");
+  receiverIframe.setAttribute("remote", "true");
+  receiverIframe.setAttribute("mozbrowser", "true");
+  receiverIframe.setAttribute("mozpresentation", receiverUrl);
+  receiverIframe.setAttribute("src", receiverUrl);
 
-    // This event is triggered when the iframe calls "alert".
-    receiverIframe.addEventListener("mozbrowsershowmodalprompt", function receiverListener(aEvent) {
-      var message = aEvent.detail.message;
-      if (/^OK /.exec(message)) {
-        ok(true, "Message from iframe: " + message);
-      } else if (/^KO /.exec(message)) {
-        ok(false, "Message from iframe: " + message);
-      } else if (/^INFO /.exec(message)) {
-        info("Message from iframe: " + message);
-      } else if (/^COMMAND /.exec(message)) {
-        var command = JSON.parse(message.replace(/^COMMAND /, ""));
-        gScript.sendAsyncMessage(command.name, command.data);
-      } else if (/^DONE$/.exec(message)) {
-        ok(true, "Messaging from iframe complete.");
-        receiverIframe.removeEventListener("mozbrowsershowmodalprompt", receiverListener);
+  // This event is triggered when the iframe calls "alert".
+  receiverIframe.addEventListener("mozbrowsershowmodalprompt", function receiverListener(aEvent) {
+    var message = aEvent.detail.message;
+    if (/^OK /.exec(message)) {
+      ok(true, "Message from iframe: " + message);
+    } else if (/^KO /.exec(message)) {
+      ok(false, "Message from iframe: " + message);
+    } else if (/^INFO /.exec(message)) {
+      info("Message from iframe: " + message);
+    } else if (/^COMMAND /.exec(message)) {
+      var command = JSON.parse(message.replace(/^COMMAND /, ""));
+      gScript.sendAsyncMessage(command.name, command.data);
+    } else if (/^DONE$/.exec(message)) {
+      ok(true, "Messaging from iframe complete.");
+      receiverIframe.removeEventListener("mozbrowsershowmodalprompt", receiverListener);
 
-        isReceiverFinished = true;
+      isReceiverFinished = true;
 
-        if (isNonReceiverFinished) {
-          teardown();
-        }
+      if (isNonReceiverFinished) {
+        teardown();
       }
-    });
+    }
+  });
 
-    var promise = new Promise(function(aResolve, aReject) {
-      document.body.appendChild(receiverIframe);
+  var promise = new Promise(function(aResolve, aReject) {
+    document.body.appendChild(receiverIframe);
 
-      aResolve(receiverIframe);
-    });
-    obs.notifyObservers(promise, "setup-request-promise");
+    aResolve(receiverIframe);
+  });
+  obs.notifyObservers(promise, "setup-request-promise");
 
-    // Create a non-receiver OOP iframe.
-    var nonReceiverIframe = document.createElement("iframe");
-    nonReceiverIframe.setAttribute("remote", "true");
-    nonReceiverIframe.setAttribute("mozbrowser", "true");
-    nonReceiverIframe.setAttribute("src", nonReceiverUrl);
+  // Create a non-receiver OOP iframe.
+  var nonReceiverIframe = document.createElement("iframe");
+  nonReceiverIframe.setAttribute("remote", "true");
+  nonReceiverIframe.setAttribute("mozbrowser", "true");
+  nonReceiverIframe.setAttribute("src", nonReceiverUrl);
 
-    // This event is triggered when the iframe calls "alert".
-    nonReceiverIframe.addEventListener("mozbrowsershowmodalprompt", function nonReceiverListener(aEvent) {
-      var message = aEvent.detail.message;
-      if (/^OK /.exec(message)) {
-        ok(true, "Message from iframe: " + message);
-      } else if (/^KO /.exec(message)) {
-        ok(false, "Message from iframe: " + message);
-      } else if (/^INFO /.exec(message)) {
-        info("Message from iframe: " + message);
-      } else if (/^COMMAND /.exec(message)) {
-        var command = JSON.parse(message.replace(/^COMMAND /, ""));
-        gScript.sendAsyncMessage(command.name, command.data);
-      } else if (/^DONE$/.exec(message)) {
-        ok(true, "Messaging from iframe complete.");
-        nonReceiverIframe.removeEventListener("mozbrowsershowmodalprompt", nonReceiverListener);
+  // This event is triggered when the iframe calls "alert".
+  nonReceiverIframe.addEventListener("mozbrowsershowmodalprompt", function nonReceiverListener(aEvent) {
+    var message = aEvent.detail.message;
+    if (/^OK /.exec(message)) {
+      ok(true, "Message from iframe: " + message);
+    } else if (/^KO /.exec(message)) {
+      ok(false, "Message from iframe: " + message);
+    } else if (/^INFO /.exec(message)) {
+      info("Message from iframe: " + message);
+    } else if (/^COMMAND /.exec(message)) {
+      var command = JSON.parse(message.replace(/^COMMAND /, ""));
+      gScript.sendAsyncMessage(command.name, command.data);
+    } else if (/^DONE$/.exec(message)) {
+      ok(true, "Messaging from iframe complete.");
+      nonReceiverIframe.removeEventListener("mozbrowsershowmodalprompt", nonReceiverListener);
 
-        isNonReceiverFinished = true;
+      isNonReceiverFinished = true;
 
-        if (isReceiverFinished) {
-          teardown();
-        }
+      if (isReceiverFinished) {
+        teardown();
       }
-    });
-
-    document.body.appendChild(nonReceiverIframe);
+    }
+  });
 
-    gScript.addMessageListener("offer-received", function offerReceivedHandler() {
-      gScript.removeMessageListener("offer-received", offerReceivedHandler);
-      info("An offer is received.");
-    });
+  document.body.appendChild(nonReceiverIframe);
 
-    gScript.addMessageListener("answer-sent", function answerSentHandler(aIsValid) {
-      gScript.removeMessageListener("answer-sent", answerSentHandler);
-      ok(aIsValid, "A valid answer is sent.");
-    });
+  gScript.addMessageListener("offer-received", function offerReceivedHandler() {
+    gScript.removeMessageListener("offer-received", offerReceivedHandler);
+    info("An offer is received.");
+  });
+
+  gScript.addMessageListener("answer-sent", function answerSentHandler(aIsValid) {
+    gScript.removeMessageListener("answer-sent", answerSentHandler);
+    ok(aIsValid, "A valid answer is sent.");
+  });
 
-    gScript.addMessageListener("control-channel-closed", function controlChannelClosedHandler(aReason) {
-      gScript.removeMessageListener("control-channel-closed", controlChannelClosedHandler);
-      is(aReason, SpecialPowers.Cr.NS_OK, "The control channel is closed normally.");
-    });
+  gScript.addMessageListener("control-channel-closed", function controlChannelClosedHandler(aReason) {
+    gScript.removeMessageListener("control-channel-closed", controlChannelClosedHandler);
+    is(aReason, SpecialPowers.Cr.NS_OK, "The control channel is closed normally.");
+  });
 
-    gScript.addMessageListener("data-transport-notification-enabled", function dataTransportNotificationEnabledHandler() {
-      gScript.removeMessageListener("data-transport-notification-enabled", dataTransportNotificationEnabledHandler);
-      info("Data notification is enabled for data transport channel.");
-    });
+  gScript.addMessageListener("data-transport-notification-enabled", function dataTransportNotificationEnabledHandler() {
+    gScript.removeMessageListener("data-transport-notification-enabled", dataTransportNotificationEnabledHandler);
+    info("Data notification is enabled for data transport channel.");
+  });
 
-    gScript.addMessageListener("data-transport-closed", function dataTransportClosedHandler(aReason) {
-      gScript.removeMessageListener("data-transport-closed", dataTransportClosedHandler);
-      is(aReason, SpecialPowers.Cr.NS_OK, "The data transport should be closed normally.");
-    });
-
-    aResolve();
+  gScript.addMessageListener("data-transport-closed", function dataTransportClosedHandler(aReason) {
+    gScript.removeMessageListener("data-transport-closed", dataTransportClosedHandler);
+    is(aReason, SpecialPowers.Cr.NS_OK, "The data transport should be closed normally.");
   });
 }
 
 function testIncomingSessionRequest() {
   return new Promise(function(aResolve, aReject) {
     gScript.addMessageListener("receiver-launching", function launchReceiverHandler(aSessionId) {
       gScript.removeMessageListener("receiver-launching", launchReceiverHandler);
       info("Trying to launch receiver page.");
@@ -149,18 +144,18 @@ function teardown() {
     gScript.destroy();
     SimpleTest.finish();
   });
 
   gScript.sendAsyncMessage("teardown");
 }
 
 function runTests() {
-  setup().
-  then(testIncomingSessionRequest);
+  setup();
+  testIncomingSessionRequest();
 }
 
 SimpleTest.waitForExplicitFinish();
 SpecialPowers.pushPermissions([
   {type: "presentation-device-manage", allow: false, context: document},
   {type: "browser", allow: true, context: document},
 ], function() {
   SpecialPowers.pushPrefEnv({ "set": [["dom.presentation.enabled", true],

--- a/dom/presentation/tests/mochitest/test_presentation_terminate.js
+++ b/dom/presentation/tests/mochitest/test_presentation_terminate.js
@@ -60,18 +60,17 @@ function setup() {
       }
     });
 
     var promise = new Promise(function(aResolve, aReject) {
       document.body.appendChild(receiverIframe);
       aResolve(receiverIframe);
     });
 
-    var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-                           .getService(SpecialPowers.Ci.nsIObserverService);
+    var obs = SpecialPowers.Services.obs;
     obs.notifyObservers(promise, "setup-request-promise");
   });
 
   gScript.addMessageListener("promise-setup-ready", function promiseSetupReadyHandler() {
     debug("Got message: promise-setup-ready");
     gScript.removeMessageListener("promise-setup-ready",
                                   promiseSetupReadyHandler);
     gScript.sendAsyncMessage("trigger-on-session-request", receiverUrl);

--- a/dom/presentation/tests/mochitest/test_presentation_terminate_establish_connection_error.js
+++ b/dom/presentation/tests/mochitest/test_presentation_terminate_establish_connection_error.js
@@ -65,18 +65,17 @@ function setup() {
       }
     });
 
     var promise = new Promise(function(aResolve, aReject) {
       document.body.appendChild(receiverIframe);
       aResolve(receiverIframe);
     });
 
-    var obs = SpecialPowers.Cc["@mozilla.org/observer-service;1"]
-                           .getService(SpecialPowers.Ci.nsIObserverService);
+    var obs = SpecialPowers.Services.obs;
     obs.notifyObservers(promise, "setup-request-promise");
   });
 
   gScript.addMessageListener("promise-setup-ready", function promiseSetupReadyHandler() {
     debug("Got message: promise-setup-ready");
     gScript.removeMessageListener("promise-setup-ready",
                                   promiseSetupReadyHandler);
     gScript.sendAsyncMessage("trigger-on-session-request", receiverUrl);

--- a/dom/presentation/tests/xpcshell/test_multicast_dns_device_provider.js
+++ b/dom/presentation/tests/xpcshell/test_multicast_dns_device_provider.js
@@ -243,17 +243,17 @@ function registerService() {
           this.serviceUnregistered++;
         }
       };
     },
     resolveService(serviceInfo, listener) {},
     serviceRegistered: 0,
     serviceUnregistered: 0
   };
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
 
   Assert.equal(mockObj.serviceRegistered, 0);
   Assert.equal(mockObj.serviceUnregistered, 0);
 
   // Register
   provider.listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
@@ -286,17 +286,17 @@ function noRegisterService() {
     startDiscovery(serviceType, listener) {},
     registerService(serviceInfo, listener) {
       deferred.resolve();
       Assert.ok(false, "should not register service if not discoverable");
     },
     resolveService(serviceInfo, listener) {},
   };
 
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
 
   // Try register
   provider.listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
     addDevice(device) {},
     removeDevice(device) {},
@@ -332,17 +332,17 @@ function registerServiceDynamically() {
           this.serviceUnregistered++;
         }
       };
     },
     resolveService(serviceInfo, listener) {},
     serviceRegistered: 0,
     serviceUnregistered: 0
   };
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
 
   Assert.equal(mockObj.serviceRegistered, 0);
   Assert.equal(mockObj.serviceRegistered, 0);
 
   // Try Register
   provider.listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
@@ -402,17 +402,17 @@ function addDevice() {
       Assert.equal(serviceInfo.serviceType, mockDevice.serviceType);
       listener.onServiceResolved(createDevice(mockDevice.host,
                                               mockDevice.port,
                                               mockDevice.serviceName,
                                               mockDevice.serviceType));
     }
   };
 
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = new TestPresentationDeviceListener();
   Assert.equal(listener.count(), 0);
 
   // Start discovery
   provider.listener = listener;
   Assert.equal(listener.count(), 1);
 
@@ -452,17 +452,17 @@ function filterDevice() {
       Assert.equal(serviceInfo.serviceType, mockDevice.serviceType);
       listener.onServiceResolved(createDevice(mockDevice.host,
                                               mockDevice.port,
                                               mockDevice.serviceName,
                                               mockDevice.serviceType));
     }
   };
 
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
     addDevice(device) {
       let tests = [
         { requestedUrl: "app://fling-player.gaiamobile.org/index.html", supported: true },
         { requestedUrl: "app://notification-receiver.gaiamobile.org/index.html", supported: true },
@@ -488,18 +488,16 @@ function filterDevice() {
 
   provider.listener = listener;
 }
 
 function handleSessionRequest() {
   Services.prefs.setBoolPref(PREF_DISCOVERY, true);
   Services.prefs.setBoolPref(PREF_DISCOVERABLE, false);
 
-  const testUrl = "http://example.com";
-  const testPresentationId = "test-presentation-id";
   const testDeviceName = "test-device-name";
 
   Services.prefs.setCharPref(PREF_DEVICENAME, testDeviceName);
 
   let mockDevice = createDevice("device.local",
                                 12345,
                                 "service.name",
                                 SERVICE_TYPE);
@@ -537,30 +535,30 @@ function handleSessionRequest() {
     },
     id: "",
     version: LATEST_VERSION,
     isCompatibleServer(version) {
       return this.version === version;
     }
   };
 
-  let contractHookSD = new ContractHook(SD_CONTRACT_ID, mockSDObj);
-  let contractHookServer = new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
+  new ContractHook(SD_CONTRACT_ID, mockSDObj);
+  new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
     addDevice(device) {
       this.device = device;
     },
   };
 
   provider.listener = listener;
 
-  let controlChannel = listener.device.establishControlChannel();
+  listener.device.establishControlChannel();
 
   Assert.equal(mockServerObj.request.deviceInfo.id, mockDevice.host);
   Assert.equal(mockServerObj.request.deviceInfo.address, mockDevice.host);
   Assert.equal(mockServerObj.request.deviceInfo.port, mockDevice.port);
   Assert.equal(mockServerObj.id, testDeviceName);
 
   provider.listener = null;
 
@@ -603,18 +601,18 @@ function handleOnSessionRequest() {
     sessionRequest() {},
     close() {},
     id: "",
     version: LATEST_VERSION,
     port: 0,
     listener: null,
   };
 
-  let contractHookSD = new ContractHook(SD_CONTRACT_ID, mockSDObj);
-  let contractHookServer = new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
+  new ContractHook(SD_CONTRACT_ID, mockSDObj);
+  new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
     addDevice(device) {},
     removeDevice(device) {},
     updateDevice(device) {},
     onSessionRequest(device, url, presentationId, controlChannel) {
@@ -670,18 +668,18 @@ function handleOnSessionRequestFromUnkno
     sessionRequest() {},
     close() {},
     id: "",
     version: LATEST_VERSION,
     port: 0,
     listener: null,
   };
 
-  let contractHookSD = new ContractHook(SD_CONTRACT_ID, mockSDObj);
-  let contractHookServer = new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
+  new ContractHook(SD_CONTRACT_ID, mockSDObj);
+  new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
     addDevice(device) {
       Assert.ok(false, "shouldn't create any new device");
     },
     removeDevice(device) {
@@ -724,27 +722,26 @@ function handleOnSessionRequestFromUnkno
   provider.listener = null;
 
   run_next_test();
 }
 
 function noAddDevice() {
   Services.prefs.setBoolPref(PREF_DISCOVERY, false);
 
-  let mockDevice = createDevice("device.local", 12345, "service.name", SERVICE_TYPE);
   let mockObj = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIDNSServiceDiscovery]),
     startDiscovery(serviceType, listener) {
       Assert.ok(false, "shouldn't perform any device discovery");
     },
     registerService(serviceInfo, listener) {},
     resolveService(serviceInfo, listener) {
     }
   };
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
 
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
     addDevice(device) {},
     removeDevice(device) {},
     updateDevice(device) {},
@@ -815,18 +812,18 @@ function ignoreIncompatibleDevice() {
     isCompatibleServer(version) {
       return false;
     },
     port: 54321,
     certFingerprint: "mock-cert-fingerprint",
     listener: null,
   };
 
-  let contractHookSD = new ContractHook(SD_CONTRACT_ID, mockSDObj);
-  let contractHookServer = new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
+  new ContractHook(SD_CONTRACT_ID, mockSDObj);
+  new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = new TestPresentationDeviceListener();
 
   // Register service
   provider.listener = listener;
 
   deferred.promise.then(function() {
     Assert.equal(mockServerObj.id, mockDevice.host);
@@ -900,18 +897,18 @@ function ignoreSelfDevice() {
     isCompatibleServer(version) {
       return this.version === version;
     },
     port: 54321,
     certFingerprint: "mock-cert-fingerprint",
     listener: null,
   };
 
-  let contractHookSD = new ContractHook(SD_CONTRACT_ID, mockSDObj);
-  let contractHookServer = new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
+  new ContractHook(SD_CONTRACT_ID, mockSDObj);
+  new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = new TestPresentationDeviceListener();
 
   // Register service
   provider.listener = listener;
   deferred.promise.then(() => {
     Assert.equal(mockServerObj.id, mockDevice.host);
 
@@ -952,17 +949,17 @@ function addDeviceDynamically() {
       Assert.equal(serviceInfo.serviceType, mockDevice.serviceType);
       listener.onServiceResolved(createDevice(mockDevice.host,
                                               mockDevice.port,
                                               mockDevice.serviceName,
                                               mockDevice.serviceType));
     }
   };
 
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = new TestPresentationDeviceListener();
   provider.listener = listener;
   Assert.equal(listener.count(), 0);
 
   // Enable discovery
   Services.prefs.setBoolPref(PREF_DISCOVERY, true);
   Assert.equal(listener.count(), 1);
@@ -1017,17 +1014,17 @@ function updateDevice() {
       } else if (serviceInfo.serviceName == "N2") {
         listener.onServiceResolved(mockDevice2);
       } else {
         Assert.ok(false);
       }
     }
   };
 
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
 
     addDevice(device) {
       Assert.ok(!this.isDeviceAdded);
       Assert.equal(device.id, mockDevice1.host);
@@ -1108,17 +1105,17 @@ function diffDiscovery() {
       } else if (serviceInfo.serviceName == "N3") {
         listener.onServiceResolved(mockDevice3);
       } else {
         Assert.ok(false);
       }
     }
   };
 
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = new TestPresentationDeviceListener();
   Assert.equal(listener.count(), 0);
 
   // Start discovery
   provider.listener = listener; // discover: N1, N2
   Assert.equal(listener.count(), 2);
   Assert.equal(listener.devices["A.local"].name, mockDevice1.serviceName);
@@ -1187,17 +1184,17 @@ function serverClosed() {
       listener.onServiceResolved(createDevice(mockDevice.host,
                                               mockDevice.port,
                                               mockDevice.serviceName,
                                               mockDevice.serviceType));
     },
     serviceRegistered: 0,
     serviceUnregistered: 0
   };
-  let contractHook = new ContractHook(SD_CONTRACT_ID, mockObj);
+  new ContractHook(SD_CONTRACT_ID, mockObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
 
   Assert.equal(mockObj.serviceRegistered, 0);
   Assert.equal(mockObj.serviceUnregistered, 0);
 
   // Register
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
@@ -1267,18 +1264,18 @@ function serverRetry() {
     close() {},
     id: "",
     version: LATEST_VERSION,
     port: 0,
     certFingerprint: "mock-cert-fingerprint",
     listener: null,
   };
 
-  let contractHookSD = new ContractHook(SD_CONTRACT_ID, mockSDObj);
-  let contractHookServer = new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
+  new ContractHook(SD_CONTRACT_ID, mockSDObj);
+  new ContractHook(SERVER_CONTRACT_ID, mockServerObj);
   let provider = Cc[PROVIDER_CONTRACT_ID].createInstance(Ci.nsIPresentationDeviceProvider);
   let listener = {
     QueryInterface: ChromeUtils.generateQI([Ci.nsIPresentationDeviceListener,
                                             Ci.nsISupportsWeakReference]),
     addDevice(device) {},
     removeDevice(device) {},
     updateDevice(device) {},
     onSessionRequest(device, url, presentationId, controlChannel) {}
@@ -1288,17 +1285,17 @@ function serverRetry() {
 }
 
 function run_test() {
   // Need profile dir to store the key / cert
   do_get_profile();
   // Ensure PSM is initialized
   Cc["@mozilla.org/psm;1"].getService(Ci.nsISupports);
 
-  let infoHook = new ContractHook(INFO_CONTRACT_ID, MockDNSServiceInfo);
+  new ContractHook(INFO_CONTRACT_ID, MockDNSServiceInfo);
 
   registerCleanupFunction(() => {
     Services.prefs.clearUserPref(PREF_DISCOVERY);
     Services.prefs.clearUserPref(PREF_DISCOVERABLE);
   });
 
   add_test(registerService);
   add_test(noRegisterService);

--- a/dom/presentation/tests/xpcshell/test_presentation_device_manager.js
+++ b/dom/presentation/tests/xpcshell/test_presentation_device_manager.js
@@ -150,17 +150,16 @@ function sessionRequest() {
 
     run_next_test();
   }, "presentation-session-request");
   manager.QueryInterface(Ci.nsIPresentationDeviceListener)
          .onSessionRequest(testDevice, testUrl, testPresentationId, testControlChannel);
 }
 
 function terminateRequest() {
-  let testUrl = "http://www.example.org/";
   let testPresentationId = "test-presentation-id";
   let testControlChannel = new TestPresentationControlChannel();
   let testIsFromReceiver = true;
   Services.obs.addObserver(function observer(subject, topic, data) {
     Services.obs.removeObserver(observer, topic);
 
     let request = subject.QueryInterface(Ci.nsIPresentationTerminateRequest);
 

--- a/dom/presentation/tests/xpcshell/test_presentation_state_machine.js
+++ b/dom/presentation/tests/xpcshell/test_presentation_state_machine.js
@@ -62,37 +62,37 @@ function launch() {
   Assert.equal(receiverState.state, State.CONNECTED, "receiver in connected state");
 
   controllerState.launch(testPresentationId, testUrl);
   mockReceiverChannel.notifyLaunch = function(presentationId, url) {
     Assert.equal(receiverState.state, State.CONNECTED, "receiver in connected state");
     Assert.equal(presentationId, testPresentationId, "expected presentationId received");
     Assert.equal(url, testUrl, "expected url received");
 
-    mockControllerChannel.notifyLaunch = function(presentationId) {
+    mockControllerChannel.notifyLaunch = function(presId) {
       Assert.equal(controllerState.state, State.CONNECTED, "controller in connected state");
-      Assert.equal(presentationId, testPresentationId, "expected presentationId received from ack");
+      Assert.equal(presId, testPresentationId, "expected presentationId received from ack");
 
       run_next_test();
     };
   };
 }
 
 function terminateByController() {
   Assert.equal(controllerState.state, State.CONNECTED, "controller in connected state");
   Assert.equal(receiverState.state, State.CONNECTED, "receiver in connected state");
 
   controllerState.terminate(testPresentationId);
   mockReceiverChannel.notifyTerminate = function(presentationId) {
     Assert.equal(receiverState.state, State.CONNECTED, "receiver in connected state");
     Assert.equal(presentationId, testPresentationId, "expected presentationId received");
 
-    mockControllerChannel.notifyTerminate = function(presentationId) {
+    mockControllerChannel.notifyTerminate = function(presId) {
       Assert.equal(controllerState.state, State.CONNECTED, "controller in connected state");
-      Assert.equal(presentationId, testPresentationId, "expected presentationId received from ack");
+      Assert.equal(presId, testPresentationId, "expected presentationId received from ack");
 
       run_next_test();
     };
 
     receiverState.terminateAck(presentationId);
   };
 }
 
@@ -100,19 +100,19 @@ function terminateByReceiver() {
   Assert.equal(controllerState.state, State.CONNECTED, "controller in connected state");
   Assert.equal(receiverState.state, State.CONNECTED, "receiver in connected state");
 
   receiverState.terminate(testPresentationId);
   mockControllerChannel.notifyTerminate = function(presentationId) {
     Assert.equal(controllerState.state, State.CONNECTED, "controller in connected state");
     Assert.equal(presentationId, testPresentationId, "expected presentationId received");
 
-    mockReceiverChannel.notifyTerminate = function(presentationId) {
+    mockReceiverChannel.notifyTerminate = function(presId) {
       Assert.equal(receiverState.state, State.CONNECTED, "receiver in connected state");
-      Assert.equal(presentationId, testPresentationId, "expected presentationId received from ack");
+      Assert.equal(presId, testPresentationId, "expected presentationId received from ack");
       run_next_test();
     };
 
     controllerState.terminateAck(presentationId);
   };
 }
 
 function exchangeSDP() {
@@ -130,18 +130,18 @@ function exchangeSDP() {
     mockControllerChannel.notifyAnswer = function(answer) {
       Assert.equal(answer, testAnswer, "expected answer received");
 
       controllerState.updateIceCandidate(testIceCandidate);
       mockReceiverChannel.notifyIceCandidate = function(candidate) {
         Assert.equal(candidate, testIceCandidate, "expected ice candidate received in receiver");
 
         receiverState.updateIceCandidate(testIceCandidate);
-        mockControllerChannel.notifyIceCandidate = function(candidate) {
-          Assert.equal(candidate, testIceCandidate, "expected ice candidate received in controller");
+        mockControllerChannel.notifyIceCandidate = function(controllerCandidate) {
+          Assert.equal(controllerCandidate, testIceCandidate, "expected ice candidate received in controller");
 
           run_next_test();
         };
       };
     };
   };
 }
 
@@ -152,18 +152,18 @@ function disconnect() {
 
   mockReceiverChannel.notifyDisconnected = function(reason) {
     Assert.equal(reason, Cr.NS_OK, "receive close reason");
     Assert.equal(receiverState.state, State.CLOSED, "receiver in closed state");
 
     receiverState.onChannelClosed(Cr.NS_OK, true);
     Assert.equal(receiverState.state, State.CLOSED, "receiver in closed state");
 
-    mockControllerChannel.notifyDisconnected = function(reason) {
-      Assert.equal(reason, Cr.NS_OK, "receive close reason");
+    mockControllerChannel.notifyDisconnected = function(disconnectReason) {
+      Assert.equal(disconnectReason, Cr.NS_OK, "receive close reason");
       Assert.equal(controllerState.state, State.CLOSED, "controller in closed state");
 
       run_next_test();
     };
     controllerState.onChannelClosed(Cr.NS_OK, true);
   };
 }
 
@@ -178,18 +178,18 @@ function receiverDisconnect() {
 
   mockControllerChannel.notifyDisconnected = function(reason) {
     Assert.equal(reason, Cr.NS_OK, "receive close reason");
     Assert.equal(controllerState.state, State.CLOSED, "controller in closed state");
 
     controllerState.onChannelClosed(Cr.NS_OK, true);
     Assert.equal(controllerState.state, State.CLOSED, "controller in closed state");
 
-    mockReceiverChannel.notifyDisconnected = function(reason) {
-      Assert.equal(reason, Cr.NS_OK, "receive close reason");
+    mockReceiverChannel.notifyDisconnected = function(disconnectReason) {
+      Assert.equal(disconnectReason, Cr.NS_OK, "receive close reason");
       Assert.equal(receiverState.state, State.CLOSED, "receiver in closed state");
 
       run_next_test();
     };
     receiverState.onChannelClosed(Cr.NS_OK, true);
   };
 }
 
@@ -205,18 +205,18 @@ function abnormalDisconnect() {
 
   mockReceiverChannel.notifyDisconnected = function(reason) {
     Assert.equal(reason, testErrorReason, "receive abnormal close reason");
     Assert.equal(receiverState.state, State.CLOSED, "receiver in closed state");
 
     receiverState.onChannelClosed(Cr.NS_OK, true);
     Assert.equal(receiverState.state, State.CLOSED, "receiver in closed state");
 
-    mockControllerChannel.notifyDisconnected = function(reason) {
-      Assert.equal(reason, testErrorReason, "receive abnormal close reason");
+    mockControllerChannel.notifyDisconnected = function(disconnectReason) {
+      Assert.equal(disconnectReason, testErrorReason, "receive abnormal close reason");
       Assert.equal(controllerState.state, State.CLOSED, "controller in closed state");
 
       run_next_test();
     };
     controllerState.onChannelClosed(Cr.NS_OK, true);
   };
 }