--- a/.eslintignore
+++ b/.eslintignore
@@ -115,16 +115,17 @@ devtools/client/webconsole/**
 !devtools/client/webconsole/panel.js
 !devtools/client/webconsole/jsterm.js
 devtools/client/webide/**
 devtools/server/**
 !devtools/server/actors/webbrowser.js
 !devtools/server/actors/styles.js
 devtools/shared/*.js
 !devtools/shared/css-lexer.js
+!devtools/shared/task.js
 devtools/shared/*.jsm
 devtools/shared/apps/**
 devtools/shared/client/**
 devtools/shared/discovery/**
 devtools/shared/gcli/**
 !devtools/shared/gcli/templater.js
 devtools/shared/heapsnapshot/**
 devtools/shared/inspector/**

--- a/devtools/client/aboutdebugging/modules/worker.js
+++ b/devtools/client/aboutdebugging/modules/worker.js
@@ -1,15 +1,15 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "gDevTools",
   "devtools/client/framework/devtools", true);
 loader.lazyRequireGetter(this, "TargetFactory",
   "devtools/client/framework/target", true);
 loader.lazyRequireGetter(this, "Toolbox",
   "devtools/client/framework/toolbox", true);
 

--- a/devtools/client/animationinspector/animation-controller.js
+++ b/devtools/client/animationinspector/animation-controller.js
@@ -9,18 +9,18 @@
    imports globals from animation-controller.js */
 /* globals AnimationsPanel */
 /* eslint no-unused-vars: [2, {"vars": "local", "args": "none"}] */
 
 "use strict";
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
-Cu.import("resource://gre/modules/Task.jsm");
 var { loader, require } = Cu.import("resource://devtools/shared/Loader.jsm");
+var { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
 loader.lazyRequireGetter(this, "AnimationsFront", "devtools/server/actors/animation", true);
 
 const { LocalizationHelper } = require("devtools/client/shared/l10n");
 
 const STRINGS_URI = "chrome://devtools/locale/animationinspector.properties";

--- a/devtools/client/animationinspector/components/animation-details.js
+++ b/devtools/client/animationinspector/components/animation-details.js
@@ -1,18 +1,17 @@
 /* -*- 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 {Cu} = require("chrome");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {createNode, TimeScale} = require("devtools/client/animationinspector/utils");
 const {Keyframes} = require("devtools/client/animationinspector/components/keyframes");
 
 /**
  * UI component responsible for displaying detailed information for a given
  * animation.
  * This includes information about timing, easing, keyframes, animated

--- a/devtools/client/animationinspector/components/animation-target-node.js
+++ b/devtools/client/animationinspector/components/animation-target-node.js
@@ -1,18 +1,17 @@
 /* -*- 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 {Cu} = require("chrome");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {DomNodePreview} = require("devtools/client/inspector/shared/dom-node-preview");
 
 // Map dom node fronts by animation fronts so we don't have to get them from the
 // walker every time the timeline is refreshed.
 var nodeFronts = new WeakMap();
 
 /**

--- a/devtools/client/canvasdebugger/canvasdebugger.js
+++ b/devtools/client/canvasdebugger/canvasdebugger.js
@@ -16,18 +16,17 @@ const { CallWatcherFront } = require("de
 const { CanvasFront } = require("devtools/server/actors/canvas");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const { LocalizationHelper } = require("devtools/client/shared/l10n");
 const { Heritage, WidgetMethods, setNamedTimeout, clearNamedTimeout,
         setConditionalTimeout } = require("devtools/client/shared/widgets/view-helpers");
 
 const CANVAS_ACTOR_RECORDING_ATTEMPT = DevToolsUtils.testing ? 500 : 5000;
 
-XPCOMUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 XPCOMUtils.defineLazyModuleGetter(this, "PluralForm",
   "resource://gre/modules/PluralForm.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "FileUtils",
   "resource://gre/modules/FileUtils.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",

--- a/devtools/client/canvasdebugger/test/head.js
+++ b/devtools/client/canvasdebugger/test/head.js
@@ -1,16 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 var { generateUUID } = Cc["@mozilla.org/uuid-generator;1"].getService(Ci.nsIUUIDGenerator);
-var { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
 var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 
 var Services = require("Services");
 var promise = require("promise");
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { DebuggerClient } = require("devtools/shared/client/main");
 var { DebuggerServer } = require("devtools/server/main");
 var { CallWatcherFront } = require("devtools/server/actors/call-watcher");

--- a/devtools/client/debugger/content/actions/breakpoints.js
+++ b/devtools/client/debugger/content/actions/breakpoints.js
@@ -5,16 +5,17 @@
 
 const constants = require("../constants");
 const promise = require("promise");
 const { asPaused } = require("../utils");
 const { PROMISE } = require("devtools/client/shared/redux/middleware/promise");
 const {
   getSource, getBreakpoint, getBreakpoints, makeLocationId
 } = require("../queries");
+const { Task } = require("devtools/shared/task");
 
 // Because breakpoints are just simple data structures, we still need
 // a way to lookup the actual client instance to talk to the server.
 // We keep an internal database of clients based off of actor ID.
 const BREAKPOINT_CLIENT_STORE = new Map();
 
 function setBreakpointClient(actor, client) {
   BREAKPOINT_CLIENT_STORE.set(actor, client);

--- a/devtools/client/debugger/content/actions/event-listeners.js
+++ b/devtools/client/debugger/content/actions/event-listeners.js
@@ -2,16 +2,17 @@
  * 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 constants = require("../constants");
 const { asPaused } = require("../utils");
 const { reportException } = require("devtools/shared/DevToolsUtils");
 const { setNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
+const { Task } = require("devtools/shared/task");
 
 const FETCH_EVENT_LISTENERS_DELAY = 200; // ms
 
 function fetchEventListeners() {
   return (dispatch, getState) => {
     // Make sure we"re not sending a batch of closely repeated requests.
     // This can easily happen whenever new sources are fetched.
     setNamedTimeout("event-listeners-fetch", FETCH_EVENT_LISTENERS_DELAY, () => {

--- a/devtools/client/debugger/content/actions/sources.js
+++ b/devtools/client/debugger/content/actions/sources.js
@@ -4,16 +4,17 @@
 "use strict";
 
 const constants = require("../constants");
 const promise = require("promise");
 const Services = require("Services");
 const { dumpn } = require("devtools/shared/DevToolsUtils");
 const { PROMISE, HISTOGRAM_ID } = require("devtools/client/shared/redux/middleware/promise");
 const { getSource, getSourceText } = require("../queries");
+const { Task } = require("devtools/shared/task");
 
 const NEW_SOURCE_IGNORED_URLS = ["debugger eval code", "XStringBundle"];
 const FETCH_SOURCE_RESPONSE_DELAY = 200; // ms
 
 function getSourceClient(source) {
   return gThreadClient.source(source);
 }
 

--- a/devtools/client/debugger/content/utils.js
+++ b/devtools/client/debugger/content/utils.js
@@ -1,16 +1,17 @@
 /* -*- 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 { reportException } = require("devtools/shared/DevToolsUtils");
+const { Task } = require("devtools/shared/task");
 
 function asPaused(client, func) {
   if (client.state != "paused") {
     return Task.spawn(function* () {
       yield client.interrupt();
       let result;
 
       try {

--- a/devtools/client/debugger/content/views/sources-view.js
+++ b/devtools/client/debugger/content/views/sources-view.js
@@ -18,16 +18,17 @@ const actions = Object.assign(
   require("../actions/breakpoints")
 );
 const { bindActionCreators } = require("devtools/client/shared/vendor/redux");
 const {
   Heritage,
   WidgetMethods,
   setNamedTimeout
 } = require("devtools/client/shared/widgets/view-helpers");
+const { Task } = require("devtools/shared/task");
 
 const NEW_SOURCE_DISPLAY_DELAY = 200; // ms
 const FUNCTION_SEARCH_POPUP_POSITION = "topcenter bottomleft";
 const BREAKPOINT_LINE_TOOLTIP_MAX_LENGTH = 1000; // chars
 const BREAKPOINT_CONDITIONAL_POPUP_POSITION = "before_start";
 const BREAKPOINT_CONDITIONAL_POPUP_OFFSET_X = 7; // px
 const BREAKPOINT_CONDITIONAL_POPUP_OFFSET_Y = -3; // px
 

--- a/devtools/client/debugger/debugger-controller.js
+++ b/devtools/client/debugger/debugger-controller.js
@@ -144,22 +144,20 @@ var {Toolbox} = require("devtools/client
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var promise = require("devtools/shared/deprecated-sync-thenables");
 var Editor = require("devtools/client/sourceeditor/editor");
 var DebuggerEditor = require("devtools/client/sourceeditor/debugger");
 var {Tooltip} = require("devtools/client/shared/widgets/Tooltip");
 var FastListWidget = require("devtools/client/shared/widgets/FastListWidget");
 var {LocalizationHelper} = require("devtools/client/shared/l10n");
 var {PrefsHelper} = require("devtools/client/shared/prefs");
+var {Task} = require("devtools/shared/task");
 
 XPCOMUtils.defineConstant(this, "EVENTS", EVENTS);
 
-XPCOMUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
-
 XPCOMUtils.defineLazyModuleGetter(this, "Parser",
   "resource://devtools/shared/Parser.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "ShortcutUtils",
   "resource://gre/modules/ShortcutUtils.jsm");
 
 XPCOMUtils.defineLazyServiceGetter(this, "clipboardHelper",
   "@mozilla.org/widget/clipboardhelper;1", "nsIClipboardHelper");

--- a/devtools/client/dom/dom-panel.js
+++ b/devtools/client/dom/dom-panel.js
@@ -6,17 +6,17 @@
 "use strict";
 
 const { Cu } = require("chrome");
 const { defer } = require("sdk/core/promise");
 const { ObjectClient } = require("devtools/shared/client/main");
 
 const promise = require("promise");
 const EventEmitter = require("devtools/shared/event-emitter");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 /**
  * This object represents DOM panel. It's responsibility is to
  * render Document Object Model of the current debugger target.
  */
 function DomPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;

--- a/devtools/client/framework/connect/connect.js
+++ b/devtools/client/framework/connect/connect.js
@@ -3,24 +3,24 @@
 /* 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";
 
 var Cu = Components.utils;
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-Cu.import("resource://gre/modules/Task.jsm");
 var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 var Services = require("Services");
 var {gDevTools} = require("devtools/client/framework/devtools");
 var {TargetFactory} = require("devtools/client/framework/target");
 var {Toolbox} = require("devtools/client/framework/toolbox");
 var promise = require("promise");
 var {DebuggerClient} = require("devtools/shared/client/main");
+var {Task} = require("devtools/shared/task");
 
 var gClient;
 var gConnectionTimeout;
 
 XPCOMUtils.defineLazyGetter(window, "l10n", function () {
   return Services.strings.createBundle("chrome://devtools/locale/connection-screen.properties");
 });
 

--- a/devtools/client/framework/sidebar.js
+++ b/devtools/client/framework/sidebar.js
@@ -4,17 +4,17 @@
  * 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/. */
 
 const {Cu} = require("chrome");
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 var Services = require("Services");
-var {Task} = require("resource://gre/modules/Task.jsm");
+var {Task} = require("devtools/shared/task");
 var EventEmitter = require("devtools/shared/event-emitter");
 var Telemetry = require("devtools/client/shared/telemetry");
 
 const XULNS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 /**
  * ToolSidebar provides methods to register tabs in the sidebar.
  * It's assumed that the sidebar contains a xul:tabbox.

--- a/devtools/client/framework/source-location.js
+++ b/devtools/client/framework/source-location.js
@@ -1,14 +1,14 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { assert } = require("devtools/shared/DevToolsUtils");
 
 /**
  * A manager class that wraps a TabTarget and listens to source changes
  * from source maps and resolves non-source mapped locations to the source mapped
  * versions and back and forth, and creating smart elements with a location that
  * auto-update when the source changes (from pretty printing, source maps loading, etc)
  *

--- a/devtools/client/framework/target-from-url.js
+++ b/devtools/client/framework/target-from-url.js
@@ -4,17 +4,17 @@
 
 "use strict";
 
 const { Cu, Ci } = require("chrome");
 
 const { TargetFactory } = require("devtools/client/framework/target");
 const { DebuggerServer } = require("devtools/server/main");
 const { DebuggerClient } = require("devtools/shared/client/main");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 /**
  * Construct a Target for a given URL object having various query parameters:
  *
  * type: tab, process
  *    {String} The type of target to connect to.  Currently tabs and processes are supported types.
  *
  * If type="tab":

--- a/devtools/client/framework/test/shared-head.js
+++ b/devtools/client/framework/test/shared-head.js
@@ -22,17 +22,17 @@ const {console} = scopedCuImport("resour
 const {ScratchpadManager} = scopedCuImport("resource://devtools/client/scratchpad/scratchpad-manager.jsm");
 const {loader, require} = scopedCuImport("resource://devtools/shared/Loader.jsm");
 
 const {gDevTools} = require("devtools/client/framework/devtools");
 const {TargetFactory} = require("devtools/client/framework/target");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 let promise = require("promise");
 const Services = require("Services");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const {KeyShortcuts} = require("devtools/client/shared/key-shortcuts");
 
 const TEST_DIR = gTestPath.substr(0, gTestPath.lastIndexOf("/"));
 const CHROME_URL_ROOT = TEST_DIR + "/";
 const URL_ROOT = CHROME_URL_ROOT.replace("chrome://mochitests/content/",
                                          "http://example.com/");
 const URL_ROOT_SSL = CHROME_URL_ROOT.replace("chrome://mochitests/content/",
                                              "https://example.com/");

--- a/devtools/client/framework/toolbox-highlighter-utils.js
+++ b/devtools/client/framework/toolbox-highlighter-utils.js
@@ -2,17 +2,17 @@
 /* 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 promise = require("promise");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 
 /**
  * Client-side highlighter shared module.
  * To be used by toolbox panels that need to highlight DOM elements.
  *
  * Highlighting and selecting elements is common enough that it needs to be at
  * toolbox level, accessible by any panel that needs it.

--- a/devtools/client/framework/toolbox-init.js
+++ b/devtools/client/framework/toolbox-init.js
@@ -14,17 +14,17 @@ if (url.search.length > 1) {
   const Ci = Components.interfaces;
   const { gDevTools } = Cu.import("resource://devtools/client/framework/gDevTools.jsm", {});
   const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
   const { targetFromURL } = require("devtools/client/framework/target-from-url");
   const { Toolbox } = require("devtools/client/framework/toolbox");
   const { TargetFactory } = require("devtools/client/framework/target");
   const { DebuggerServer } = require("devtools/server/main");
   const { DebuggerClient } = require("devtools/shared/client/main");
-  const { Task } = require("resource://gre/modules/Task.jsm");
+  const { Task } = require("devtools/shared/task");
 
   // `host` is the frame element loading the toolbox.
   let host = window.QueryInterface(Ci.nsIInterfaceRequestor)
                    .getInterface(Ci.nsIDOMWindowUtils)
                    .containerElement;
 
   // Specify the default tool to open
   let tool = url.searchParams.get("tool");

--- a/devtools/client/framework/toolbox-options.js
+++ b/devtools/client/framework/toolbox-options.js
@@ -4,17 +4,17 @@
  * 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 Services = require("Services");
 const promise = require("promise");
 const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const {gDevTools} = require("devtools/client/framework/devtools");
 
 exports.OptionsPanel = OptionsPanel;
 
 XPCOMUtils.defineLazyGetter(this, "l10n", function () {
   let bundle = Services.strings.createBundle("chrome://devtools/locale/toolbox.properties");
   let l10n = function (name, ...aArgs) {
     try {

--- a/devtools/client/framework/toolbox-process-window.js
+++ b/devtools/client/framework/toolbox-process-window.js
@@ -13,17 +13,17 @@ var { loader, require } = Cu.import("res
 loader.require("devtools/client/framework/devtools-browser");
 
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { TargetFactory } = require("devtools/client/framework/target");
 var { Toolbox } = require("devtools/client/framework/toolbox");
 var Services = require("Services");
 var { DebuggerClient } = require("devtools/shared/client/main");
 var { PrefsHelper } = require("devtools/client/shared/prefs");
-var { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+var { Task } = require("devtools/shared/task");
 
 /**
  * Shortcuts for accessing various debugger preferences.
  */
 var Prefs = new PrefsHelper("devtools.debugger", {
   chromeDebuggingHost: ["Char", "chrome-debugging-host"],
   chromeDebuggingPort: ["Int", "chrome-debugging-port"]
 });

--- a/devtools/client/framework/toolbox.js
+++ b/devtools/client/framework/toolbox.js
@@ -14,17 +14,17 @@ const MIN_ZOOM = 0.5;
 const MAX_ZOOM = 2;
 const OS_HISTOGRAM = "DEVTOOLS_OS_ENUMERATED_PER_USER";
 const OS_IS_64_BITS = "DEVTOOLS_OS_IS_64_BITS_PER_USER";
 const SCREENSIZE_HISTOGRAM = "DEVTOOLS_SCREEN_RESOLUTION_ENUMERATED_PER_USER";
 
 var {Cc, Ci, Cu} = require("chrome");
 var promise = require("promise");
 var Services = require("Services");
-var {Task} = require("resource://gre/modules/Task.jsm");
+var {Task} = require("devtools/shared/task");
 var {gDevTools} = require("devtools/client/framework/devtools");
 var EventEmitter = require("devtools/shared/event-emitter");
 var Telemetry = require("devtools/client/shared/telemetry");
 var HUDService = require("devtools/client/webconsole/hudservice");
 var viewSource = require("devtools/client/shared/view-source");
 var { attachThread, detachThread } = require("./attach-thread");
 
 Cu.import("resource://devtools/client/scratchpad/scratchpad-manager.jsm");

--- a/devtools/client/inspector/fonts/fonts.js
+++ b/devtools/client/inspector/fonts/fonts.js
@@ -1,26 +1,23 @@
 /* -*- 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 {Cu} = require("chrome");
 const {gDevTools} = require("devtools/client/framework/devtools");
 const Services = require("Services");
 
 const DEFAULT_PREVIEW_TEXT = "Abc";
 const PREVIEW_UPDATE_DELAY = 150;
 
-Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 
 function FontInspector(inspector, window) {
   this.inspector = inspector;
   this.pageStyle = this.inspector.pageStyle;
   this.chromeDoc = window.document;
   this.init();
 }
 

--- a/devtools/client/inspector/inspector-panel.js
+++ b/devtools/client/inspector/inspector-panel.js
@@ -10,16 +10,17 @@ const {Cc, Ci, Cu} = require("chrome");
 
 var Services = require("Services");
 var promise = require("promise");
 var EventEmitter = require("devtools/shared/event-emitter");
 var clipboard = require("sdk/clipboard");
 var {HostType} = require("devtools/client/framework/toolbox").Toolbox;
 const {executeSoon} = require("devtools/shared/DevToolsUtils");
 var {KeyShortcuts} = require("devtools/client/shared/key-shortcuts");
+var {Task} = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "CSS", "CSS");
 
 loader.lazyRequireGetter(this, "CommandUtils", "devtools/client/shared/developer-toolbar", true);
 loader.lazyRequireGetter(this, "ComputedViewTool", "devtools/client/inspector/computed/computed", true);
 loader.lazyRequireGetter(this, "FontInspector", "devtools/client/inspector/fonts/fonts", true);
 loader.lazyRequireGetter(this, "HTMLBreadcrumbs", "devtools/client/inspector/breadcrumbs", true);
 loader.lazyRequireGetter(this, "InspectorSearch", "devtools/client/inspector/inspector-search", true);

--- a/devtools/client/inspector/inspector-search.js
+++ b/devtools/client/inspector/inspector-search.js
@@ -2,16 +2,17 @@
  * 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 {Cu, Ci} = require("chrome");
 
 const promise = require("promise");
+const {Task} = require("devtools/shared/task");
 
 loader.lazyGetter(this, "system", () => require("devtools/shared/system"));
 loader.lazyGetter(this, "EventEmitter", () => require("devtools/shared/event-emitter"));
 loader.lazyGetter(this, "AutocompletePopup", () => require("devtools/client/shared/autocomplete-popup").AutocompletePopup);
 
 // Maximum number of selector suggestions shown in the panel.
 const MAX_SUGGESTIONS = 15;
 

--- a/devtools/client/inspector/layout/layout.js
+++ b/devtools/client/inspector/layout/layout.js
@@ -2,17 +2,17 @@
 /* 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} = require("chrome");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const {InplaceEditor, editableItem} =
       require("devtools/client/shared/inplace-editor");
 const {ReflowFront} = require("devtools/server/actors/layout");
 const {LocalizationHelper} = require("devtools/client/shared/l10n");
 
 const STRINGS_URI = "chrome://devtools/locale/shared.properties";
 const SHARED_L10N = new LocalizationHelper(STRINGS_URI);
 const NUMERIC = /^-?[\d\.]+$/;

--- a/devtools/client/inspector/markup/markup.js
+++ b/devtools/client/inspector/markup/markup.js
@@ -36,17 +36,17 @@ const promise = require("promise");
 const Services = require("Services");
 const {Tooltip} = require("devtools/client/shared/widgets/Tooltip");
 const EventEmitter = require("devtools/shared/event-emitter");
 const Heritage = require("sdk/core/heritage");
 const {parseAttribute} =
       require("devtools/client/shared/node-attribute-parser");
 const ELLIPSIS = Services.prefs.getComplexValue("intl.ellipsis",
       Ci.nsIPrefLocalizedString).data;
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const {scrollIntoViewIfNeeded} = require("devtools/shared/layout/utils");
 const {PrefObserver} = require("devtools/client/styleeditor/utils");
 const {KeyShortcuts} = require("devtools/client/shared/key-shortcuts");
 const {template} = require("devtools/shared/gcli/templater");
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 loader.lazyRequireGetter(this, "CSS", "CSS");

--- a/devtools/client/inspector/rules/rules.js
+++ b/devtools/client/inspector/rules/rules.js
@@ -6,17 +6,17 @@
 /* globals gDevTools */
 
 "use strict";
 
 const {Cc, Ci} = require("chrome");
 const promise = require("promise");
 const Services = require("Services");
 const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const {Tools} = require("devtools/client/definitions");
 const {CssLogic} = require("devtools/shared/inspector/css-logic");
 const {ELEMENT_STYLE} = require("devtools/server/actors/styles");
 const {OutputParser} = require("devtools/client/shared/output-parser");
 const {PrefObserver, PREF_ORIG_SOURCES} =
       require("devtools/client/styleeditor/utils");
 const {ElementStyle} =
       require("devtools/client/inspector/rules/models/element-style");

--- a/devtools/client/inspector/shared/dom-node-preview.js
+++ b/devtools/client/inspector/shared/dom-node-preview.js
@@ -1,15 +1,14 @@
 /* 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 {Cu} = require("chrome");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {createNode} = require("devtools/client/animationinspector/utils");
 const { LocalizationHelper } = require("devtools/client/shared/l10n");
 
 const STRINGS_URI = "chrome://devtools/locale/inspector.properties";
 const L10N = new LocalizationHelper(STRINGS_URI);
 
 /**

--- a/devtools/client/inspector/shared/style-inspector-menu.js
+++ b/devtools/client/inspector/shared/style-inspector-menu.js
@@ -4,17 +4,17 @@
  * 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/. */
 /* global _strings */
 
 "use strict";
 
 const {PREF_ORIG_SOURCES} = require("devtools/client/styleeditor/utils");
 const Services = require("Services");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "overlays",
   "devtools/client/inspector/shared/style-inspector-overlays");
 loader.lazyServiceGetter(this, "clipboardHelper",
   "@mozilla.org/widget/clipboardhelper;1", "nsIClipboardHelper");
 loader.lazyGetter(this, "_strings", () => {
   return Services.strings
   .createBundle("chrome://devtools-shared/locale/styleinspector.properties");

--- a/devtools/client/inspector/shared/style-inspector-overlays.js
+++ b/devtools/client/inspector/shared/style-inspector-overlays.js
@@ -7,27 +7,26 @@
 "use strict";
 
 // The style-inspector overlays are:
 // - tooltips that appear when hovering over property values
 // - editor tooltips that appear when clicking color swatches, etc.
 // - in-content highlighters that appear when hovering over property values
 // - etc.
 
-const {Cu} = require("chrome");
 const {
   Tooltip,
   SwatchColorPickerTooltip,
   SwatchCubicBezierTooltip,
   CssDocsTooltip,
   SwatchFilterTooltip
 } = require("devtools/client/shared/widgets/Tooltip");
 const EventEmitter = require("devtools/shared/event-emitter");
 const promise = require("promise");
-Cu.import("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const Services = require("Services");
 
 const PREF_IMAGE_TOOLTIP_SIZE = "devtools.inspector.imagePreviewTooltipSize";
 
 // Types of existing tooltips
 const TOOLTIP_IMAGE_TYPE = "image";
 const TOOLTIP_FONTFAMILY_TYPE = "font-family";
 

--- a/devtools/client/memory/initializer.js
+++ b/devtools/client/memory/initializer.js
@@ -6,17 +6,17 @@
 
 const { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 const BrowserLoaderModule = {};
 Cu.import("resource://devtools/client/shared/browser-loader.js", BrowserLoaderModule);
 const { require } = BrowserLoaderModule.BrowserLoader({
   baseURI: "resource://devtools/client/memory/",
   window: this
 });
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { createFactory, createElement } = require("devtools/client/shared/vendor/react");
 const ReactDOM = require("devtools/client/shared/vendor/react-dom");
 const { Provider } = require("devtools/client/shared/vendor/react-redux");
 const App = createFactory(require("devtools/client/memory/app"));
 const Store = require("devtools/client/memory/store");
 const { assert } = require("devtools/shared/DevToolsUtils");
 
 /**

--- a/devtools/client/memory/panel.js
+++ b/devtools/client/memory/panel.js
@@ -1,16 +1,16 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const EventEmitter = require("devtools/shared/event-emitter");
 const { MemoryFront } = require("devtools/server/actors/memory");
 const HeapAnalysesClient = require("devtools/shared/heapsnapshot/HeapAnalysesClient");
 const promise = require("promise");
 
 function MemoryPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;

--- a/devtools/client/memory/test/chrome/head.js
+++ b/devtools/client/memory/test/chrome/head.js
@@ -7,17 +7,17 @@ var { classes: Cc, interfaces: Ci, utils
 Cu.import("resource://testing-common/Assert.jsm");
 
 Cu.import("resource://devtools/client/shared/browser-loader.js");
 var { require } = BrowserLoader({
   baseURI: "resource://devtools/client/memory/",
   window: this
 });
 var Services = require("Services");
-var { Task } = require("resource://gre/modules/Task.jsm");
+var { Task } = require("devtools/shared/task");
 
 var EXPECTED_DTU_ASSERT_FAILURE_COUNT = 0;
 
 SimpleTest.registerCleanupFunction(function () {
   if (DevToolsUtils.assertionFailureCount !== EXPECTED_DTU_ASSERT_FAILURE_COUNT) {
     ok(false, "Should have had the expected number of DevToolsUtils.assert() failures. Expected " +
        EXPECTED_DTU_ASSERT_FAILURE_COUNT + ", got " + DevToolsUtils.assertionFailureCount);
   }

--- a/devtools/client/memory/test/unit/head.js
+++ b/devtools/client/memory/test/unit/head.js
@@ -12,17 +12,17 @@ var DevToolsUtils = require("devtools/sh
 DevToolsUtils.testing = true;
 DevToolsUtils.dumpn.wantLogging = true;
 DevToolsUtils.dumpv.wantVerbose = false;
 
 var { OS } = require("resource://gre/modules/osfile.jsm");
 var { FileUtils } = require("resource://gre/modules/FileUtils.jsm");
 var { TargetFactory } = require("devtools/client/framework/target");
 var promise = require("promise");
-var { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+var { Task } = require("devtools/shared/task");
 var { expectState } = require("devtools/server/actors/common");
 var HeapSnapshotFileUtils = require("devtools/shared/heapsnapshot/HeapSnapshotFileUtils");
 var HeapAnalysesClient = require("devtools/shared/heapsnapshot/HeapAnalysesClient");
 var { addDebuggerToGlobal } = require("resource://gre/modules/jsdebugger.jsm");
 var Store = require("devtools/client/memory/store");
 var { L10N } = require("devtools/client/memory/utils");
 var SYSTEM_PRINCIPAL = Cc["@mozilla.org/systemprincipal;1"].createInstance(Ci.nsIPrincipal);
 

--- a/devtools/client/netmonitor/har/har-automation.js
+++ b/devtools/client/netmonitor/har/har-automation.js
@@ -1,19 +1,18 @@
 /* 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 { Cu, Ci } = require("chrome");
+const { Ci } = require("chrome");
 const { Class } = require("sdk/core/heritage");
 const { resolve } = require("promise");
 const Services = require("Services");
-
-Cu.import("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "HarCollector", "devtools/client/netmonitor/har/har-collector", true);
 loader.lazyRequireGetter(this, "HarExporter", "devtools/client/netmonitor/har/har-exporter", true);
 loader.lazyRequireGetter(this, "HarUtils", "devtools/client/netmonitor/har/har-utils", true);
 
 const prefDomain = "devtools.netmonitor.har.";
 
 // Helper tracer. Should be generic sharable by other modules (bug 1171927)

--- a/devtools/client/netmonitor/netmonitor-controller.js
+++ b/devtools/client/netmonitor/netmonitor-controller.js
@@ -114,33 +114,31 @@ Cu.import("resource://devtools/client/sh
 
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const promise = require("promise");
 const Services = require("Services");
 const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
 const EventEmitter = require("devtools/shared/event-emitter");
 const Editor = require("devtools/client/sourceeditor/editor");
 const {TimelineFront} = require("devtools/server/actors/timeline");
+const { Task } = require("devtools/shared/task");
 
 XPCOMUtils.defineConstant(this, "EVENTS", EVENTS);
 XPCOMUtils.defineConstant(this, "ACTIVITY_TYPE", ACTIVITY_TYPE);
 XPCOMUtils.defineConstant(this, "Editor", Editor);
 
 XPCOMUtils.defineLazyModuleGetter(this, "Chart",
   "resource://devtools/client/shared/widgets/Chart.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "Curl",
   "resource://devtools/client/shared/Curl.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "CurlUtils",
   "resource://devtools/client/shared/Curl.jsm");
 
-XPCOMUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
-
 XPCOMUtils.defineLazyModuleGetter(this, "PluralForm",
   "resource://gre/modules/PluralForm.jsm");
 
 XPCOMUtils.defineLazyServiceGetter(this, "clipboardHelper",
   "@mozilla.org/widget/clipboardhelper;1", "nsIClipboardHelper");
 
 XPCOMUtils.defineLazyServiceGetter(this, "DOMParser",
   "@mozilla.org/xmlextras/domparser;1", "nsIDOMParser");

--- a/devtools/client/netmonitor/panel.js
+++ b/devtools/client/netmonitor/panel.js
@@ -2,17 +2,17 @@
 /* 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 promise = require("promise");
 const EventEmitter = require("devtools/shared/event-emitter");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 function NetMonitorPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;
 
   this._view = this.panelWin.NetMonitorView;
   this._controller = this.panelWin.NetMonitorController;
   this._controller._target = this.target;

--- a/devtools/client/netmonitor/test/head.js
+++ b/devtools/client/netmonitor/test/head.js
@@ -1,17 +1,17 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
-var { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
 var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 var { gDevTools } = require("devtools/client/framework/devtools");
+var { Task } = require("devtools/shared/task");
 var { CurlUtils } = Cu.import("resource://devtools/client/shared/Curl.jsm", {});
 var Services = require("Services");
 var promise = require("promise");
 var NetworkHelper = require("devtools/shared/webconsole/network-helper");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var { TargetFactory } = require("devtools/client/framework/target");
 var { Toolbox } = require("devtools/client/framework/toolbox");
 

--- a/devtools/client/performance/components/test/head.js
+++ b/devtools/client/performance/components/test/head.js
@@ -5,17 +5,17 @@
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 Cu.import("resource://testing-common/Assert.jsm");
 var { Promise: promise } = Cu.import("resource://gre/modules/Promise.jsm", {});
 var { require } = Cu.import("resource://gre/modules/devtools/shared/Loader.jsm", {});
 var { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
-var { Task } = require("resource://gre/modules/Task.jsm");
+var { Task } = require("devtools/shared/task");
 var { TargetFactory } = require("devtools/client/framework/target");
 var { Toolbox } = require("devtools/client/framework/toolbox");
 
 DevToolsUtils.testing = true;
 var { require: browserRequire } = BrowserLoader({
   baseURI: "resource://devtools/client/performance/",
   window: this
 });

--- a/devtools/client/performance/legacy/actors.js
+++ b/devtools/client/performance/legacy/actors.js
@@ -1,14 +1,14 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 const promise = require("promise");
 const EventEmitter = require("devtools/shared/event-emitter");
 const { Poller } = require("devtools/client/shared/poller");
 
 const CompatUtils = require("devtools/client/performance/legacy/compatibility");
 const RecordingUtils = require("devtools/shared/performance/recording-utils");
 const { TimelineFront } = require("devtools/server/actors/timeline");

--- a/devtools/client/performance/legacy/front.js
+++ b/devtools/client/performance/legacy/front.js
@@ -1,15 +1,15 @@
 /* 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 { Cu } = require("chrome");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 const Services = require("Services");
 const promise = require("promise");
 const { extend } = require("sdk/util/object");
 
 const Actors = require("devtools/client/performance/legacy/actors");
 const { LegacyPerformanceRecording } = require("devtools/client/performance/legacy/recording");
 const { importRecording } = require("devtools/client/performance/legacy/recording");

--- a/devtools/client/performance/legacy/recording.js
+++ b/devtools/client/performance/legacy/recording.js
@@ -1,15 +1,15 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 const PerformanceIO = require("devtools/client/performance/modules/io");
 const RecordingUtils = require("devtools/shared/performance/recording-utils");
 const { PerformanceRecordingCommon } = require("devtools/shared/performance/recording-common");
 const { merge } = require("sdk/util/object");
 
 /**
  * Model for a wholistic profile, containing the duration, profiling data,

--- a/devtools/client/performance/modules/widgets/graphs.js
+++ b/devtools/client/performance/modules/widgets/graphs.js
@@ -3,17 +3,17 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
 /**
  * This file contains the base line graph that all Performance line graphs use.
  */
 
 const { Cc, Ci, Cu, Cr } = require("chrome");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { Heritage } = require("devtools/client/shared/widgets/view-helpers");
 const LineGraphWidget = require("devtools/client/shared/widgets/LineGraphWidget");
 const BarGraphWidget = require("devtools/client/shared/widgets/BarGraphWidget");
 const MountainGraphWidget = require("devtools/client/shared/widgets/MountainGraphWidget");
 const { CanvasGraphUtils } = require("devtools/client/shared/widgets/Graphs");
 
 const promise = require("promise");
 const EventEmitter = require("devtools/shared/event-emitter");

--- a/devtools/client/performance/panel.js
+++ b/devtools/client/performance/panel.js
@@ -1,17 +1,17 @@
 /* -*- Mode: javascript; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "EventEmitter",
   "devtools/shared/event-emitter");
 
 function PerformancePanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this.toolbox = toolbox;

--- a/devtools/client/performance/performance-controller.js
+++ b/devtools/client/performance/performance-controller.js
@@ -5,17 +5,17 @@
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 var BrowserLoaderModule = {};
 Cu.import("resource://devtools/client/shared/browser-loader.js", BrowserLoaderModule);
 var { loader, require } = BrowserLoaderModule.BrowserLoader({
   baseURI: "resource://devtools/client/performance/",
   window: this
 });
-var { Task } = require("resource://gre/modules/Task.jsm");
+var { Task } = require("devtools/shared/task");
 var { Heritage, ViewHelpers, WidgetMethods, setNamedTimeout, clearNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 var { gDevTools } = require("devtools/client/framework/devtools");
 
 // Events emitted by various objects in the panel.
 var EVENTS = require("devtools/client/performance/events");
 Object.defineProperty(this, "EVENTS", {
   value: EVENTS,
   enumerable: true,

--- a/devtools/client/performance/test/helpers/profiler-mm-utils.js
+++ b/devtools/client/performance/test/helpers/profiler-mm-utils.js
@@ -5,17 +5,17 @@
 
 /**
  * The following functions are used in testing to control and inspect
  * the nsIProfiler in child process content. These should be called from
  * the parent process.
  */
 
 const { Cc, Ci } = require("chrome");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 const FRAME_SCRIPT_UTILS_URL = "chrome://devtools/content/shared/frame-script-utils.js";
 
 let gMM = null;
 
 /**
  * Loads the relevant frame scripts into the provided browser's message manager.
  */

--- a/devtools/client/performance/test/helpers/wait-utils.js
+++ b/devtools/client/performance/test/helpers/wait-utils.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 /* globals dump */
 
 const { CC } = require("chrome");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const { once, observeOnce } = require("devtools/client/performance/test/helpers/event-utils");
 
 /**
  * Blocks the main thread for the specified amount of time.
  */
 exports.busyWait = function (time) {
   dump(`Busy waiting for: ${time} milliseconds.\n`);

--- a/devtools/client/projecteditor/lib/project.js
+++ b/devtools/client/projecteditor/lib/project.js
@@ -7,17 +7,17 @@
 const { Cu } = require("chrome");
 const { Class } = require("sdk/core/heritage");
 const { EventTarget } = require("sdk/event/target");
 const { emit } = require("sdk/event/core");
 const { scope, on, forget } = require("devtools/client/projecteditor/lib/helpers/event");
 const prefs = require("sdk/preferences/service");
 const { LocalStore } = require("devtools/client/projecteditor/lib/stores/local");
 const { OS } = Cu.import("resource://gre/modules/osfile.jsm", {});
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 const promise = require("promise");
 const { TextEncoder, TextDecoder } = require("sdk/io/buffer");
 const url = require("sdk/url");
 
 const gDecoder = new TextDecoder();
 const gEncoder = new TextEncoder();
 
 /**

--- a/devtools/client/projecteditor/lib/projecteditor.js
+++ b/devtools/client/projecteditor/lib/projecteditor.js
@@ -14,17 +14,17 @@ const { registeredPlugins } = require("d
 const { EventTarget } = require("sdk/event/target");
 const { on, forget } = require("devtools/client/projecteditor/lib/helpers/event");
 const { emit } = require("sdk/event/core");
 const { merge } = require("sdk/util/object");
 const promise = require("promise");
 const { ViewHelpers } = require("devtools/client/shared/widgets/view-helpers");
 const { DOMHelpers } = Cu.import("resource://devtools/client/shared/DOMHelpers.jsm");
 const Services = require("Services");
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 const ITCHPAD_URL = "chrome://devtools/content/projecteditor/chrome/content/projecteditor.xul";
 const { confirm } = require("devtools/client/projecteditor/lib/helpers/prompts");
 const { getLocalizedString } = require("devtools/client/projecteditor/lib/helpers/l10n");
 
 // Enabled Plugins
 require("devtools/client/projecteditor/lib/plugins/dirty/dirty");
 require("devtools/client/projecteditor/lib/plugins/delete/delete");
 require("devtools/client/projecteditor/lib/plugins/new/new");

--- a/devtools/client/projecteditor/lib/stores/local.js
+++ b/devtools/client/projecteditor/lib/stores/local.js
@@ -4,17 +4,17 @@
  * 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/. */
 
 const { Cc, Ci, Cu, ChromeWorker } = require("chrome");
 const { Class } = require("sdk/core/heritage");
 const { OS } = Cu.import("resource://gre/modules/osfile.jsm", {});
 const { emit } = require("sdk/event/core");
 const { Store } = require("devtools/client/projecteditor/lib/stores/base");
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 const promise = require("promise");
 const Services = require("Services");
 const { on, forget } = require("devtools/client/projecteditor/lib/helpers/event");
 const { FileResource } = require("devtools/client/projecteditor/lib/stores/resource");
 
 const CHECK_LINKED_DIRECTORY_DELAY = 5000;
 const SHOULD_LIVE_REFRESH = true;
 // XXX: Ignores should be customizable

--- a/devtools/client/projecteditor/lib/stores/resource.js
+++ b/devtools/client/projecteditor/lib/stores/resource.js
@@ -11,17 +11,17 @@ const { TextEncoder, TextDecoder } = req
 const { Class } = require("sdk/core/heritage");
 const { EventTarget } = require("sdk/event/target");
 const { emit } = require("sdk/event/core");
 const URL = require("sdk/url");
 const promise = require("promise");
 const { OS } = Cu.import("resource://gre/modules/osfile.jsm", {});
 const { FileUtils } = Cu.import("resource://gre/modules/FileUtils.jsm", {});
 const mimeService = Cc["@mozilla.org/mime;1"].getService(Ci.nsIMIMEService);
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 
 const gDecoder = new TextDecoder();
 const gEncoder = new TextEncoder();
 
 /**
  * A Resource is a single file-like object that can be respresented
  * as a file for ProjectEditor.
  *

--- a/devtools/client/promisedebugger/promise-controller.js
+++ b/devtools/client/promisedebugger/promise-controller.js
@@ -7,17 +7,17 @@
 /* global PromisesPanel */
 
 "use strict";
 
 var { utils: Cu } = Components;
 const { loader, require } =
   Cu.import("resource://devtools/shared/Loader.jsm", {});
 
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "EventEmitter",
   "devtools/shared/event-emitter");
 loader.lazyRequireGetter(this, "DevToolsUtils",
   "devtools/shared/DevToolsUtils");
 loader.lazyRequireGetter(this, "PromisesFront",
   "devtools/server/actors/promises", true);

--- a/devtools/client/promisedebugger/promise-panel.js
+++ b/devtools/client/promisedebugger/promise-panel.js
@@ -1,15 +1,16 @@
 /* -*- 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/. */
 
 /* global PromisesController, promise */
+/* import-globals-from promise-controller.js */
 
 "use strict";
 
 /**
  * The main promise debugger UI.
  */
 var PromisesPanel = {
   PANEL_INITIALIZED: "panel-initialized",

--- a/devtools/client/responsive.html/actions/screenshot.js
+++ b/devtools/client/responsive.html/actions/screenshot.js
@@ -8,17 +8,17 @@
 
 const {
   TAKE_SCREENSHOT_START,
   TAKE_SCREENSHOT_END,
 } = require("./index");
 
 const { getFormatStr } = require("../utils/l10n");
 const { getToplevelWindow } = require("sdk/window/utils");
-const { Task: { spawn } } = require("resource://gre/modules/Task.jsm");
+const { Task: { spawn } } = require("devtools/shared/task");
 const e10s = require("../utils/e10s");
 
 const BASE_URL = "resource://devtools/client/responsive.html";
 const audioCamera = new window.Audio(`${BASE_URL}/audio/camera-click.mp3`);
 
 const animationFrame = () => new Promise(resolve => {
   window.requestAnimationFrame(resolve);
 });

--- a/devtools/client/responsive.html/browser/swap.js
+++ b/devtools/client/responsive.html/browser/swap.js
@@ -1,16 +1,16 @@
 /* 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 promise = require("promise");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 /**
  * Swap page content from an existing tab into a new browser within a container
  * page.  Page state is preserved by using `swapFrameLoaders`, just like when
  * you move a tab to a new window.  This provides a seamless transition for the
  * user since the page is not reloaded.
  *
  * See /devtools/docs/responsive-design-mode.md for a high level overview of how

--- a/devtools/client/responsive.html/components/browser.js
+++ b/devtools/client/responsive.html/components/browser.js
@@ -1,17 +1,17 @@
 /* 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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const { getToplevelWindow } = require("sdk/window/utils");
 const { DOM: dom, createClass, addons, PropTypes } =
   require("devtools/client/shared/vendor/react");
 
 const Types = require("../types");
 const e10s = require("../utils/e10s");
 const message = require("../utils/message");

--- a/devtools/client/responsive.html/devices.js
+++ b/devtools/client/responsive.html/devices.js
@@ -1,16 +1,16 @@
 /* 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 Services = require("Services");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { GetDevices } = require("devtools/client/shared/devices");
 const { addDevice, addDeviceType } = require("./actions/devices");
 
 const DISPLAYED_DEVICES_PREF = "devtools.responsive.html.displayedDeviceList";
 
 /**
  * Get the device catalog and load the devices onto the store.
  *

--- a/devtools/client/responsive.html/index.js
+++ b/devtools/client/responsive.html/index.js
@@ -8,17 +8,17 @@
 
 const { utils: Cu } = Components;
 const { BrowserLoader } =
   Cu.import("resource://devtools/client/shared/browser-loader.js", {});
 const { require } = BrowserLoader({
   baseURI: "resource://devtools/client/responsive.html/",
   window: this
 });
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const Telemetry = require("devtools/client/shared/telemetry");
 const { loadSheet } = require("sdk/stylesheet/utils");
 
 const { createFactory, createElement } =
   require("devtools/client/shared/vendor/react");
 const ReactDOM = require("devtools/client/shared/vendor/react-dom");
 const { Provider } = require("devtools/client/shared/vendor/react-redux");
 

--- a/devtools/client/responsive.html/manager.js
+++ b/devtools/client/responsive.html/manager.js
@@ -1,16 +1,16 @@
 /* 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 promise = require("promise");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const EventEmitter = require("devtools/shared/event-emitter");
 const { TouchEventSimulator } = require("devtools/shared/touch/simulator");
 const { getOwnerWindow } = require("sdk/tabs/utils");
 const { on, off } = require("sdk/event/core");
 const { startup } = require("sdk/window/helpers");
 const events = require("./events");
 const message = require("./utils/message");
 const { swapToInnerBrowser } = require("./browser/swap");

--- a/devtools/client/responsive.html/test/unit/head.js
+++ b/devtools/client/responsive.html/test/unit/head.js
@@ -4,16 +4,16 @@
 "use strict";
 
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
 
 const { utils: Cu } = Components;
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 
 const promise = require("promise");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const Store = require("devtools/client/responsive.html/store");
 
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 DevToolsUtils.testing = true;
 do_register_cleanup(() => {
   DevToolsUtils.testing = false;
 });

--- a/devtools/client/responsivedesign/responsivedesign.jsm
+++ b/devtools/client/responsivedesign/responsivedesign.jsm
@@ -6,17 +6,17 @@
 
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 var {loader, require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 var Telemetry = require("devtools/client/shared/telemetry");
 var {showDoorhanger} = require("devtools/client/shared/doorhanger");
 var {TouchEventSimulator} = require("devtools/shared/touch/simulator");
-var {Task} = require("resource://gre/modules/Task.jsm");
+var {Task} = require("devtools/shared/task");
 var promise = require("promise");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var Services = require("Services");
 var EventEmitter = require("devtools/shared/event-emitter");
 var {ViewHelpers} = require("devtools/client/shared/widgets/view-helpers");
 var { LocalizationHelper } = require("devtools/client/shared/l10n");
 
 loader.lazyImporter(this, "SystemAppProxy",

--- a/devtools/client/scratchpad/test/browser_scratchpad_autocomplete.js
+++ b/devtools/client/scratchpad/test/browser_scratchpad_autocomplete.js
@@ -1,17 +1,17 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 /* Bug 968896 */
 
 // Test the completions using numbers.
 const source = "0x1.";
 const completions = ["toExponential", "toFixed", "toString"];
-Cu.import("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 function test() {
   const options = { tabContent: "test scratchpad autocomplete" };
   openTabAndScratchpad(options)
     .then(Task.async(runTests))
     .then(finish, console.error);
 }
 

--- a/devtools/client/scratchpad/test/browser_scratchpad_close_toolbox.js
+++ b/devtools/client/scratchpad/test/browser_scratchpad_close_toolbox.js
@@ -1,15 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test that closing the toolbox after having opened a scratchpad leaves the
 // latter in a functioning state.
 
-var {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+var {Task} = require("devtools/shared/task");
 var {TargetFactory} = require("devtools/client/framework/target");
 
 function test() {
   const options = {
     tabContent: "test closing toolbox and then reusing scratchpad"
   };
   openTabAndScratchpad(options)
     .then(Task.async(runTests))

--- a/devtools/client/scratchpad/test/browser_scratchpad_disable_view_menu_items.js
+++ b/devtools/client/scratchpad/test/browser_scratchpad_disable_view_menu_items.js
@@ -1,15 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test if the view menu items "Larger Font" and "Smaller Font" are disabled
 // when the font size reaches the maximum/minimum values.
 
-var {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+var {Task} = require("devtools/shared/task");
 
 function test() {
   const options = {
     tabContent: 'test if view menu items "Larger Font" and "Smaller Font" are enabled/disabled.'
   };
   openTabAndScratchpad(options)
     .then(Task.async(runTests))
     .then(finish, console.error);

--- a/devtools/client/scratchpad/test/browser_scratchpad_inspect_primitives.js
+++ b/devtools/client/scratchpad/test/browser_scratchpad_inspect_primitives.js
@@ -1,15 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test that inspecting primitive values uses the object inspector, not an
 // inline comment.
 
-var {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+var {Task} = require("devtools/shared/task");
 
 function test() {
   const options = {
     tabContent: "test inspecting primitive values"
   };
   openTabAndScratchpad(options)
     .then(Task.async(runTests))
     .then(finish, console.error);

--- a/devtools/client/shadereditor/shadereditor.js
+++ b/devtools/client/shadereditor/shadereditor.js
@@ -1,28 +1,28 @@
 /* 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";
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
-Cu.import("resource://gre/modules/Task.jsm");
 Cu.import("resource://devtools/client/shared/widgets/SideMenuWidget.jsm");
 
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const promise = require("promise");
 const Services = require("Services");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {Tooltip} = require("devtools/client/shared/widgets/Tooltip");
 const Editor = require("devtools/client/sourceeditor/editor");
 const {LocalizationHelper} = require("devtools/client/shared/l10n");
 const {Heritage, WidgetMethods, setNamedTimeout} =
   require("devtools/client/shared/widgets/view-helpers");
+const {Task} = require("devtools/shared/task");
 
 // The panel's window global is an EventEmitter firing the following events:
 const EVENTS = {
   // When new programs are received from the server.
   NEW_PROGRAM: "ShaderEditor:NewProgram",
   PROGRAMS_ADDED: "ShaderEditor:ProgramsAdded",
 
   // When the vertex and fragment sources were shown in the editor.

--- a/devtools/client/shadereditor/test/head.js
+++ b/devtools/client/shadereditor/test/head.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
-var { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
 var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { Task } = require("devtools/shared/task");
 
 var Services = require("Services");
 var promise = require("promise");
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { DebuggerClient } = require("devtools/shared/client/main");
 var { DebuggerServer } = require("devtools/server/main");
 var { WebGLFront } = require("devtools/server/actors/webgl");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");

--- a/devtools/client/shared/components/test/mochitest/head.js
+++ b/devtools/client/shared/components/test/mochitest/head.js
@@ -9,17 +9,17 @@ Cu.import("resource://testing-common/Ass
 var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
 var promise = require("promise");
 var Services = require("Services");
 var { DebuggerServer } = require("devtools/server/main");
 var { DebuggerClient } = require("devtools/shared/client/main");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
-var { Task } = require("resource://gre/modules/Task.jsm");
+var { Task } = require("devtools/shared/task");
 var { TargetFactory } = require("devtools/client/framework/target");
 var { Toolbox } = require("devtools/client/framework/toolbox");
 
 DevToolsUtils.testing = true;
 var { require: browserRequire } = BrowserLoader({
   baseURI: "resource://devtools/client/shared/",
   window: this
 });

--- a/devtools/client/shared/css-parsing-utils.js
+++ b/devtools/client/shared/css-parsing-utils.js
@@ -9,21 +9,21 @@
 // parseDeclarations - parse a CSS rule into declarations
 // RuleRewriter - rewrite CSS rule text
 // parsePseudoClassesAndAttributes - parse selector and extract
 //     pseudo-classes
 // parseSingleValue - parse a single CSS property value
 
 "use strict";
 
-const {Cc, Ci, Cu} = require("chrome");
+const {Cc, Ci} = require("chrome");
 loader.lazyRequireGetter(this, "CSS", "CSS");
 const promise = require("promise");
 const {getCSSLexer} = require("devtools/shared/css-lexer");
-Cu.import("resource://gre/modules/Task.jsm", this);
+const {Task} = require("devtools/shared/task");
 loader.lazyGetter(this, "DOMUtils", () => {
   return Cc["@mozilla.org/inspector/dom-utils;1"].getService(Ci.inIDOMUtils);
 });
 
 const SELECTOR_ATTRIBUTE = exports.SELECTOR_ATTRIBUTE = 1;
 const SELECTOR_ELEMENT = exports.SELECTOR_ELEMENT = 2;
 const SELECTOR_PSEUDO_CLASS = exports.SELECTOR_PSEUDO_CLASS = 3;
 

--- a/devtools/client/shared/doorhanger.js
+++ b/devtools/client/shared/doorhanger.js
@@ -2,17 +2,17 @@
  * 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, Cc } = require("chrome");
 const Services = require("Services");
 const { DOMHelpers } = require("resource://devtools/client/shared/DOMHelpers.jsm");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { Promise } = require("resource://gre/modules/Promise.jsm");
 const { getMostRecentBrowserWindow } = require("sdk/window/utils");
 
 const XULNS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 const DEV_EDITION_PROMO_URL = "chrome://devtools/content/framework/dev-edition-promo/dev-edition-promo.xul";
 const DEV_EDITION_PROMO_ENABLED_PREF = "devtools.devedition.promo.enabled";
 const DEV_EDITION_PROMO_SHOWN_PREF = "devtools.devedition.promo.shown";
 const DEV_EDITION_PROMO_URL_PREF = "devtools.devedition.promo.url";

--- a/devtools/client/shared/frame-script-utils.js
+++ b/devtools/client/shared/frame-script-utils.js
@@ -1,17 +1,17 @@
 /* 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";
 var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
 const {require, loader} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const promise = require("promise");
-loader.lazyImporter(this, "Task", "resource://gre/modules/Task.jsm", "Task");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyGetter(this, "nsIProfilerModule", () => {
   return Cc["@mozilla.org/tools/profiler;1"].getService(Ci.nsIProfiler);
 });
 
 addMessageListener("devtools:test:history", function ({ data }) {
   content.history[data.direction]();
 });

--- a/devtools/client/shared/redux/middleware/task.js
+++ b/devtools/client/shared/redux/middleware/task.js
@@ -1,14 +1,14 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { executeSoon, isGenerator, reportException } = require("devtools/shared/DevToolsUtils");
 const ERROR_TYPE = exports.ERROR_TYPE = "@@redux/middleware/task#error";
 
 /**
  * A middleware that allows generator thunks (functions) and promise
  * to be dispatched. If it's a generator, it is called with `dispatch`
  * and `getState`, allowing the action to create multiple actions (most likely
  * asynchronously) and yield on each. If called with a promise, calls `dispatch`

--- a/devtools/client/shared/test/test-actor.js
+++ b/devtools/client/shared/test/test-actor.js
@@ -4,17 +4,17 @@
 
 "use strict";
 
 // A helper actor for inspector and markupview tests.
 
 var { Cc, Ci, Cu, Cr } = require("chrome");
 const {getRect, getElementFromPoint, getAdjustedQuads} = require("devtools/shared/layout/utils");
 const promise = require("promise");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 var DOMUtils = Cc["@mozilla.org/inspector/dom-utils;1"].getService(Ci.inIDOMUtils);
 var loader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
             .getService(Ci.mozIJSSubScriptLoader);
 
 // Set up a dummy environment so that EventUtils works. We need to be careful to
 // pass a window object into each EventUtils method we call rather than having
 // it rely on the |window| global.
 let EventUtils = {};

--- a/devtools/client/shared/view-source.js
+++ b/devtools/client/shared/view-source.js
@@ -1,15 +1,15 @@
 /* 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";
 
-loader.lazyImporter(this, "Task", "resource://gre/modules/Task.jsm");
+var { Task } = require("devtools/shared/task");
 
 var Services = require("Services");
 var {gDevTools} = require("devtools/client/framework/devtools");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 
 /**
  * Tries to open a Stylesheet file in the Style Editor. If the file is not found,
  * it is opened in source view instead.

--- a/devtools/client/shared/widgets/FlameGraph.js
+++ b/devtools/client/shared/widgets/FlameGraph.js
@@ -1,14 +1,14 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { ViewHelpers, setNamedTimeout, clearNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 const { LocalizationHelper } = require("devtools/client/shared/l10n");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "EventEmitter",
   "devtools/shared/event-emitter");
 
 loader.lazyRequireGetter(this, "getColor",

--- a/devtools/client/shared/widgets/Graphs.js
+++ b/devtools/client/shared/widgets/Graphs.js
@@ -1,16 +1,16 @@
 /* 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 { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 const { Heritage, setNamedTimeout, clearNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 const { getCurrentZoom } = require("devtools/shared/layout/utils");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "EventEmitter",
   "devtools/shared/event-emitter");
 
 loader.lazyImporter(this, "DevToolsWorker",

--- a/devtools/client/shared/widgets/LineGraphWidget.js
+++ b/devtools/client/shared/widgets/LineGraphWidget.js
@@ -1,13 +1,13 @@
 "use strict";
 
 const { Cc, Ci, Cu, Cr } = require("chrome");
 
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 const { ViewHelpers, Heritage } = require("devtools/client/shared/widgets/view-helpers");
 const { AbstractCanvasGraph, CanvasGraphUtils } = require("devtools/client/shared/widgets/Graphs");
 const { LocalizationHelper } = require("devtools/client/shared/l10n");
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const L10N = new LocalizationHelper("chrome://devtools/locale/graphs.properties");
 
 // Line graph constants.

--- a/devtools/client/shared/widgets/Tooltip.js
+++ b/devtools/client/shared/widgets/Tooltip.js
@@ -13,30 +13,29 @@ const {MdnDocsWidget} = require("devtool
 const {CSSFilterEditorWidget} = require("devtools/client/shared/widgets/FilterWidget");
 const {TooltipToggle} = require("devtools/client/shared/widgets/tooltip/TooltipToggle");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {colorUtils} = require("devtools/client/shared/css-color");
 const Heritage = require("sdk/core/heritage");
 const {Eyedropper} = require("devtools/client/eyedropper/eyedropper");
 const Editor = require("devtools/client/sourceeditor/editor");
 const Services = require("Services");
+const {Task} = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "beautify", "devtools/shared/jsbeautify/beautify");
 loader.lazyRequireGetter(this, "setNamedTimeout", "devtools/client/shared/widgets/view-helpers", true);
 loader.lazyRequireGetter(this, "clearNamedTimeout", "devtools/client/shared/widgets/view-helpers", true);
 loader.lazyRequireGetter(this, "setNamedTimeout", "devtools/client/shared/widgets/view-helpers", true);
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "VariablesView",
   "resource://devtools/client/shared/widgets/VariablesView.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "VariablesViewController",
   "resource://devtools/client/shared/widgets/VariablesViewController.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
 
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 const SPECTRUM_FRAME = "chrome://devtools/content/shared/widgets/spectrum-frame.xhtml";
 const CUBIC_BEZIER_FRAME =
       "chrome://devtools/content/shared/widgets/cubic-bezier-frame.xhtml";
 const MDN_DOCS_FRAME = "chrome://devtools/content/shared/widgets/mdn-docs-frame.xhtml";
 const FILTER_FRAME = "chrome://devtools/content/shared/widgets/filter-frame.xhtml";
 const ESCAPE_KEYCODE = Ci.nsIDOMKeyEvent.DOM_VK_ESCAPE;

--- a/devtools/client/shared/widgets/VariablesView.jsm
+++ b/devtools/client/shared/widgets/VariablesView.jsm
@@ -14,24 +14,24 @@ const LAZY_EXPAND_DELAY = 50; // ms
 const SCROLL_PAGE_SIZE_DEFAULT = 0;
 const PAGE_SIZE_SCROLL_HEIGHT_RATIO = 100;
 const PAGE_SIZE_MAX_JUMPS = 30;
 const SEARCH_ACTION_MAX_DELAY = 300; // ms
 const ITEM_FLASH_DURATION = 300; // ms
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://devtools/shared/event-emitter.js");
-Cu.import("resource://gre/modules/Task.jsm");
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const Services = require("Services");
 const { getSourceNames } = require("devtools/client/shared/source-utils");
 const promise = require("promise");
 const { Heritage, ViewHelpers, setNamedTimeout } =
   require("devtools/client/shared/widgets/view-helpers");
+const { Task } = require("devtools/shared/task");
 
 XPCOMUtils.defineLazyModuleGetter(this, "PluralForm",
   "resource://gre/modules/PluralForm.jsm");
 
 XPCOMUtils.defineLazyServiceGetter(this, "clipboardHelper",
   "@mozilla.org/widget/clipboardhelper;1",
   "nsIClipboardHelper");
 

--- a/devtools/client/shared/widgets/tooltip/TooltipToggle.js
+++ b/devtools/client/shared/widgets/tooltip/TooltipToggle.js
@@ -1,17 +1,17 @@
 /* -*- 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 {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 
 const DEFAULT_SHOW_DELAY = 50;
 
 /**
  * Tooltip helper designed to show/hide the tooltip when the mouse hovers over
  * particular nodes.
  *
  * This works by tracking mouse movements on a base container node (baseNode)

--- a/devtools/client/storage/ui.js
+++ b/devtools/client/storage/ui.js
@@ -1,16 +1,16 @@
 /* vim:set ts=2 sw=2 sts=2 et: */
 /* 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 {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {LocalizationHelper} = require("devtools/client/shared/l10n");
 
 loader.lazyRequireGetter(this, "TreeWidget",
                          "devtools/client/shared/widgets/TreeWidget", true);
 loader.lazyRequireGetter(this, "TableWidget",
                          "devtools/client/shared/widgets/TableWidget", true);
 loader.lazyRequireGetter(this, "ViewHelpers",

--- a/devtools/client/styleeditor/StyleEditorUI.jsm
+++ b/devtools/client/styleeditor/StyleEditorUI.jsm
@@ -9,17 +9,17 @@ this.EXPORTED_SYMBOLS = ["StyleEditorUI"
 
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 const {require, loader} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const Services = require("Services");
 const {NetUtil} = Cu.import("resource://gre/modules/NetUtil.jsm", {});
 const {OS} = Cu.import("resource://gre/modules/osfile.jsm", {});
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {gDevTools} = require("devtools/client/framework/devtools");
 /* import-globals-from StyleEditorUtil.jsm */
 Cu.import("resource://devtools/client/styleeditor/StyleEditorUtil.jsm");
 const {SplitView} = Cu.import("resource://devtools/client/shared/SplitView.jsm", {});
 const {StyleSheetEditor} = Cu.import("resource://devtools/client/styleeditor/StyleSheetEditor.jsm");
 loader.lazyImporter(this, "PluralForm", "resource://gre/modules/PluralForm.jsm");
 const {PrefObserver, PREF_ORIG_SOURCES} =

--- a/devtools/client/styleeditor/StyleSheetEditor.jsm
+++ b/devtools/client/styleeditor/StyleSheetEditor.jsm
@@ -13,21 +13,21 @@ const Cu = Components.utils;
 
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const Editor = require("devtools/client/sourceeditor/editor");
 const promise = require("promise");
 const {CssLogic} = require("devtools/shared/inspector/css-logic");
 const {console} = require("resource://gre/modules/Console.jsm");
 const Services = require("Services");
 const EventEmitter = require("devtools/shared/event-emitter");
+const {Task} = require("devtools/shared/task");
 
 Cu.import("resource://gre/modules/FileUtils.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 const { TextDecoder, OS } = Cu.import("resource://gre/modules/osfile.jsm", {});
-Cu.import("resource://gre/modules/Task.jsm");
 /* import-globals-from StyleEditorUtil.jsm */
 Cu.import("resource://devtools/client/styleeditor/StyleEditorUtil.jsm");
 
 const LOAD_ERROR = "error-load";
 const SAVE_ERROR = "error-save";
 
 // max update frequency in ms (avoid potential typing lag and/or flicker)
 // @see StyleEditor.updateStylesheet

--- a/devtools/client/styleeditor/styleeditor-panel.js
+++ b/devtools/client/styleeditor/styleeditor-panel.js
@@ -5,17 +5,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const {Cu} = require("chrome");
 
 var Services = require("Services");
 var promise = require("promise");
-var {Task} = require("resource://gre/modules/Task.jsm");
+var {Task} = require("devtools/shared/task");
 var {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
 var EventEmitter = require("devtools/shared/event-emitter");
 
 Cu.import("resource://devtools/client/styleeditor/StyleEditorUI.jsm");
 /* import-globals-from StyleEditorUtil.jsm */
 Cu.import("resource://devtools/client/styleeditor/StyleEditorUtil.jsm");
 
 loader.lazyGetter(this, "StyleSheetsFront",

--- a/devtools/client/webaudioeditor/includes.js
+++ b/devtools/client/webaudioeditor/includes.js
@@ -6,17 +6,17 @@
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 const { loader, require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 
 var { EventTarget } = require("sdk/event/target");
 
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 const { Class } = require("sdk/core/heritage");
 const EventEmitter = require("devtools/shared/event-emitter");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const Services = require("Services");
 const { gDevTools } = require("devtools/client/framework/devtools");
 const { LocalizationHelper } = require("devtools/client/shared/l10n");
 const { ViewHelpers } = require("devtools/client/shared/widgets/view-helpers");
 

--- a/devtools/client/webaudioeditor/test/head.js
+++ b/devtools/client/webaudioeditor/test/head.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
-var { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
 var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { Task } = require("devtools/shared/task");
 var Services = require("Services");
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { TargetFactory } = require("devtools/client/framework/target");
 var { DebuggerServer } = require("devtools/server/main");
 var { generateUUID } = Cc["@mozilla.org/uuid-generator;1"].getService(Ci.nsIUUIDGenerator);
 
 var Promise = require("promise");
 var Services = require("Services");

--- a/devtools/client/webconsole/console-output.js
+++ b/devtools/client/webconsole/console-output.js
@@ -7,32 +7,32 @@
 "use strict";
 
 const {Cc, Ci, Cu} = require("chrome");
 
 const Services = require("Services");
 
 loader.lazyImporter(this, "VariablesView", "resource://devtools/client/shared/widgets/VariablesView.jsm");
 loader.lazyImporter(this, "escapeHTML", "resource://devtools/client/shared/widgets/VariablesView.jsm");
-loader.lazyImporter(this, "Task", "resource://gre/modules/Task.jsm");
 loader.lazyImporter(this, "PluralForm", "resource://gre/modules/PluralForm.jsm");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "gDevTools", "devtools/client/framework/devtools", true);
 loader.lazyRequireGetter(this, "TableWidget", "devtools/client/shared/widgets/TableWidget", true);
 loader.lazyRequireGetter(this, "ObjectClient", "devtools/shared/client/main", true);
 
 const Heritage = require("sdk/core/heritage");
 const URI = Cc["@mozilla.org/network/io-service;1"].getService(Ci.nsIIOService);
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 const STRINGS_URI = "chrome://devtools/locale/webconsole.properties";
 
 const WebConsoleUtils = require("devtools/shared/webconsole/utils").Utils;
 const { getSourceNames } = require("devtools/client/shared/source-utils");
+const {Task} = require("devtools/shared/task");
 const l10n = new WebConsoleUtils.L10n(STRINGS_URI);
 
 const MAX_STRING_GRIP_LENGTH = 36;
 const ELLIPSIS = Services.prefs.getComplexValue("intl.ellipsis", Ci.nsIPrefLocalizedString).data;
 
 // Constants for compatibility with the Web Console output implementation before
 // bug 778766.
 // TODO: remove these once bug 778766 is fixed.

--- a/devtools/client/webconsole/hudservice.js
+++ b/devtools/client/webconsole/hudservice.js
@@ -7,17 +7,17 @@
 "use strict";
 
 const {Cc, Ci, Cu} = require("chrome");
 
 var WebConsoleUtils = require("devtools/shared/webconsole/utils").Utils;
 var Heritage = require("sdk/core/heritage");
 var {TargetFactory} = require("devtools/client/framework/target");
 var {Tools} = require("devtools/client/definitions");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 var promise = require("promise");
 var Services = require("Services");
 
 loader.lazyRequireGetter(this, "Telemetry", "devtools/client/shared/telemetry");
 loader.lazyRequireGetter(this, "WebConsoleFrame", "devtools/client/webconsole/webconsole", true);
 loader.lazyRequireGetter(this, "gDevTools", "devtools/client/framework/devtools", true);
 loader.lazyRequireGetter(this, "DebuggerServer", "devtools/server/main", true);
 loader.lazyRequireGetter(this, "DebuggerClient", "devtools/shared/client/main", true);

--- a/devtools/client/webconsole/new-console-output/test/components/head.js
+++ b/devtools/client/webconsole/new-console-output/test/components/head.js
@@ -8,17 +8,17 @@
 
 var { utils: Cu } = Components;
 
 Cu.import("resource://testing-common/Assert.jsm");
 
 var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 var { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
-var { Task } = require("resource://gre/modules/Task.jsm");
+var { Task } = require("devtools/shared/task");
 var { DebuggerServer } = require("devtools/server/main");
 var { DebuggerClient } = require("devtools/shared/client/main");
 
 const Services = require("Services");
 
 DevToolsUtils.testing = true;
 var { require: browserRequire } = BrowserLoader({
   baseURI: "resource://devtools/client/webconsole/",

--- a/devtools/client/webide/content/webide.js
+++ b/devtools/client/webide/content/webide.js
@@ -1,18 +1,16 @@
 /* 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/. */
 
 var Cc = Components.classes;
 var Cu = Components.utils;
 var Ci = Components.interfaces;
 
-Cu.import("resource://gre/modules/Task.jsm");
-
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const {gDevTools} = require("devtools/client/framework/devtools");
 const {gDevToolsBrowser} = require("devtools/client/framework/devtools-browser");
 const {Toolbox} = require("devtools/client/framework/toolbox");
 const Services = require("Services");
 const {AppProjects} = require("devtools/client/webide/modules/app-projects");
 const {Connection} = require("devtools/shared/client/connection-manager");
 const {AppManager} = require("devtools/client/webide/modules/app-manager");
@@ -21,16 +19,17 @@ const promise = require("promise");
 const ProjectEditor = require("devtools/client/projecteditor/lib/projecteditor");
 const {GetAvailableAddons} = require("devtools/client/webide/modules/addons");
 const {getJSON} = require("devtools/client/shared/getjson");
 const utils = require("devtools/client/webide/modules/utils");
 const Telemetry = require("devtools/client/shared/telemetry");
 const {RuntimeScanners} = require("devtools/client/webide/modules/runtimes");
 const {showDoorhanger} = require("devtools/client/shared/doorhanger");
 const {Simulators} = require("devtools/client/webide/modules/simulators");
+const {Task} = require("devtools/shared/task");
 
 const Strings = Services.strings.createBundle("chrome://devtools/locale/webide.properties");
 
 const HTML = "http://www.w3.org/1999/xhtml";
 const HELP_URL = "https://developer.mozilla.org/docs/Tools/WebIDE/Troubleshooting";
 
 const MAX_ZOOM = 1.4;
 const MIN_ZOOM = 0.6;

--- a/devtools/client/webide/modules/app-manager.js
+++ b/devtools/client/webide/modules/app-manager.js
@@ -13,17 +13,17 @@ const {TextEncoder, OS} = Cu.import("res
 const {AppProjects} = require("devtools/client/webide/modules/app-projects");
 const TabStore = require("devtools/client/webide/modules/tab-store");
 const {AppValidator} = require("devtools/client/webide/modules/app-validator");
 const {ConnectionManager, Connection} = require("devtools/shared/client/connection-manager");
 const {AppActorFront} = require("devtools/shared/apps/app-actor-front");
 const {getDeviceFront} = require("devtools/server/actors/device");
 const {getPreferenceFront} = require("devtools/server/actors/preference");
 const {getSettingsFront} = require("devtools/server/actors/settings");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const {RuntimeScanners, RuntimeTypes} = require("devtools/client/webide/modules/runtimes");
 const {NetUtil} = Cu.import("resource://gre/modules/NetUtil.jsm", {});
 const Telemetry = require("devtools/client/shared/telemetry");
 const {ProjectBuilding} = require("./build");
 
 const Strings = Services.strings.createBundle("chrome://devtools/locale/webide.properties");
 
 var AppManager = exports.AppManager = {

--- a/devtools/client/webide/modules/app-validator.js
+++ b/devtools/client/webide/modules/app-validator.js
@@ -3,17 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
 var {Ci, Cu, CC} = require("chrome");
 const promise = require("promise");
 
 const {FileUtils} = Cu.import("resource://gre/modules/FileUtils.jsm", {});
 const Services = require("Services");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 var XMLHttpRequest = CC("@mozilla.org/xmlextras/xmlhttprequest;1");
 var strings = Services.strings.createBundle("chrome://devtools/locale/app-manager.properties");
 
 function AppValidator({ type, location }) {
   this.type = type;
   this.location = location;
   this.errors = [];
   this.warnings = [];

--- a/devtools/client/webide/modules/build.js
+++ b/devtools/client/webide/modules/build.js
@@ -1,16 +1,16 @@
 /* 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/. */
 
 const {Cu, Cc, Ci} = require("chrome");
 
 const promise = require("promise");
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 const { TextDecoder, OS } = Cu.import("resource://gre/modules/osfile.jsm", {});
 const Subprocess = require("sdk/system/child_process/subprocess");
 
 const ProjectBuilding = exports.ProjectBuilding = {
   fetchPackageManifest: Task.async(function* (project) {
     let manifestPath = OS.Path.join(project.location, "package.json");
     let exists = yield OS.File.exists(manifestPath);
     if (!exists) {

--- a/devtools/client/webide/modules/project-list.js
+++ b/devtools/client/webide/modules/project-list.js
@@ -4,17 +4,17 @@
 
 const {Cu} = require("chrome");
 
 const Services = require("Services");
 const {AppProjects} = require("devtools/client/webide/modules/app-projects");
 const {AppManager} = require("devtools/client/webide/modules/app-manager");
 const promise = require("promise");
 const EventEmitter = require("devtools/shared/event-emitter");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const utils = require("devtools/client/webide/modules/utils");
 const Telemetry = require("devtools/client/shared/telemetry");
 
 const Strings = Services.strings.createBundle("chrome://devtools/locale/webide.properties");
 
 var ProjectList;
 
 module.exports = ProjectList = function (win, parentWindow) {

--- a/devtools/client/webide/modules/runtime-list.js
+++ b/devtools/client/webide/modules/runtime-list.js
@@ -4,17 +4,17 @@
 
 const {Cu} = require("chrome");
 
 const Services = require("Services");
 const {AppManager} = require("devtools/client/webide/modules/app-manager");
 const EventEmitter = require("devtools/shared/event-emitter");
 const {RuntimeScanners, WiFiScanner} = require("devtools/client/webide/modules/runtimes");
 const {Devices} = Cu.import("resource://devtools/shared/apps/Devices.jsm");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const utils = require("devtools/client/webide/modules/utils");
 
 const Strings = Services.strings.createBundle("chrome://devtools/locale/webide.properties");
 
 var RuntimeList;
 
 module.exports = RuntimeList = function (window, parentWindow) {
   EventEmitter.decorate(this);

--- a/devtools/client/webide/modules/simulators.js
+++ b/devtools/client/webide/modules/simulators.js
@@ -1,15 +1,15 @@
 /* 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/. */
 
 const { Cu } = require("chrome");
 const { AddonManager } = Cu.import("resource://gre/modules/AddonManager.jsm");
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 loader.lazyRequireGetter(this, "ConnectionManager", "devtools/shared/client/connection-manager", true);
 loader.lazyRequireGetter(this, "AddonSimulatorProcess", "devtools/client/webide/modules/simulator-process", true);
 loader.lazyRequireGetter(this, "OldAddonSimulatorProcess", "devtools/client/webide/modules/simulator-process", true);
 loader.lazyRequireGetter(this, "CustomSimulatorProcess", "devtools/client/webide/modules/simulator-process", true);
 const asyncStorage = require("devtools/shared/async-storage");
 const EventEmitter = require("devtools/shared/event-emitter");
 const promise = require("promise");
 const Services = require("Services");

--- a/devtools/client/webide/modules/tab-store.js
+++ b/devtools/client/webide/modules/tab-store.js
@@ -3,17 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 const { Cu } = require("chrome");
 
 const { TargetFactory } = require("devtools/client/framework/target");
 const EventEmitter = require("devtools/shared/event-emitter");
 const { Connection } = require("devtools/shared/client/connection-manager");
 const promise = require("promise");
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 
 const _knownTabStores = new WeakMap();
 
 var TabStore;
 
 module.exports = TabStore = function (connection) {
   // If we already know about this connection,
   // let's re-use the existing store.

--- a/devtools/client/webide/test/head.js
+++ b/devtools/client/webide/test/head.js
@@ -6,17 +6,17 @@
 var {utils: Cu, classes: Cc, interfaces: Ci} = Components;
 
 Cu.import("resource://gre/modules/FileUtils.jsm");
 
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const {gDevTools} = require("devtools/client/framework/devtools");
 const promise = require("promise");
 const Services = require("Services");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const {AppProjects} = require("devtools/client/webide/modules/app-projects");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 DevToolsUtils.testing = true;
 
 var TEST_BASE;
 if (window.location === "chrome://browser/content/browser.xul") {
   TEST_BASE = "chrome://mochitests/content/browser/devtools/client/webide/test/";
 } else {

--- a/devtools/server/actors/animation.js
+++ b/devtools/server/actors/animation.js
@@ -22,17 +22,17 @@
  * - WebAnimation spec:
  *   http://w3c.github.io/web-animations/
  * - WebAnimation WebIDL files:
  *   /dom/webidl/Animation*.webidl
  */
 
 const {Cu} = require("chrome");
 const promise = require("promise");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const protocol = require("devtools/shared/protocol");
 const {ActorClass, Actor, FrontClass, Front,
        Arg, method, RetVal, types} = protocol;
 // Make sure the nodeActor type is know here.
 const {NodeActor} = require("devtools/server/actors/inspector");
 const events = require("sdk/event/core");
 
 // Types of animations.

--- a/devtools/server/actors/gcli.js
+++ b/devtools/server/actors/gcli.js
@@ -1,15 +1,15 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const {
   method, Arg, Option, RetVal, Front, FrontClass, Actor, ActorClass
 } = require("devtools/shared/protocol");
 const events = require("sdk/event/core");
 const { createSystem } = require("gcli/system");
 
 /**
  * Manage remote connections that want to talk to GCLI

--- a/devtools/server/actors/heap-snapshot-file.js
+++ b/devtools/server/actors/heap-snapshot-file.js
@@ -2,21 +2,21 @@
  * 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 protocol = require("devtools/shared/protocol");
 const { method, Arg } = protocol;
 const Services = require("Services");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "DevToolsUtils",
                          "devtools/shared/DevToolsUtils");
 loader.lazyRequireGetter(this, "OS", "resource://gre/modules/osfile.jsm", true);
-loader.lazyRequireGetter(this, "Task", "resource://gre/modules/Task.jsm", true);
 loader.lazyRequireGetter(this, "HeapSnapshotFileUtils",
                          "devtools/shared/heapsnapshot/HeapSnapshotFileUtils");
 
 /**
  * The HeapSnapshotFileActor handles transferring heap snapshot files from the
  * server to the client. This has to be a global actor in the parent process
  * because child processes are sandboxed and do not have access to the file
  * system.

--- a/devtools/server/actors/inspector.js
+++ b/devtools/server/actors/inspector.js
@@ -51,17 +51,17 @@
  */
 
 const {Cc, Ci, Cu} = require("chrome");
 const Services = require("Services");
 const protocol = require("devtools/shared/protocol");
 const {Arg, Option, method, RetVal, types} = protocol;
 const {LongStringActor} = require("devtools/server/actors/string");
 const promise = require("promise");
-const {Task} = Cu.import("resource://gre/modules/Task.jsm", {});
+const {Task} = require("devtools/shared/task");
 const object = require("sdk/util/object");
 const events = require("sdk/event/core");
 const {Class} = require("sdk/core/heritage");
 const {WalkerSearch} = require("devtools/server/actors/utils/walker-search");
 const {PageStyleActor, getFontPreviewData} = require("devtools/server/actors/styles");
 const {
   HighlighterActor,
   CustomHighlighterActor,

--- a/devtools/server/actors/memory.js
+++ b/devtools/server/actors/memory.js
@@ -4,23 +4,23 @@
 
 "use strict";
 
 const { Cc, Ci, Cu, components } = require("chrome");
 const protocol = require("devtools/shared/protocol");
 const { method, RetVal, Arg, types } = protocol;
 const { Memory } = require("devtools/server/performance/memory");
 const { actorBridge } = require("devtools/server/actors/common");
+const { Task } = require("devtools/shared/task");
 loader.lazyRequireGetter(this, "events", "sdk/event/core");
 loader.lazyRequireGetter(this, "StackFrameCache",
                          "devtools/server/actors/utils/stack", true);
 loader.lazyRequireGetter(this, "FileUtils",
                          "resource://gre/modules/FileUtils.jsm", true);
 loader.lazyRequireGetter(this, "NetUtil", "resource://gre/modules/NetUtil.jsm", true);
-loader.lazyRequireGetter(this, "Task", "resource://gre/modules/Task.jsm", true);
 loader.lazyRequireGetter(this, "HeapSnapshotFileUtils",
                          "devtools/shared/heapsnapshot/HeapSnapshotFileUtils");
 loader.lazyRequireGetter(this, "ThreadSafeChromeUtils");
 
 types.addDictType("AllocationsRecordingOptions", {
   // The probability we sample any given allocation when recording
   // allocations. Must be between 0.0 and 1.0. Defaults to 1.0, or sampling
   // every allocation.

--- a/devtools/server/actors/performance.js
+++ b/devtools/server/actors/performance.js
@@ -1,17 +1,17 @@
 /* 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 { Cu } = require("chrome");
 const protocol = require("devtools/shared/protocol");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { Actor, custom, method, RetVal, Arg, Option, types, preEvent } = protocol;
 const { actorBridge } = require("devtools/server/actors/common");
 const { PerformanceRecordingActor, PerformanceRecordingFront } = require("devtools/server/actors/performance-recording");
 
 loader.lazyRequireGetter(this, "events", "sdk/event/core");
 loader.lazyRequireGetter(this, "extend", "sdk/util/object", true);
 
 loader.lazyRequireGetter(this, "PerformanceRecorder",

--- a/devtools/server/actors/storage.js
+++ b/devtools/server/actors/storage.js
@@ -8,20 +8,20 @@ const {Cc, Ci} = require("chrome");
 const events = require("sdk/event/core");
 const protocol = require("devtools/shared/protocol");
 const {LongStringActor} = require("devtools/server/actors/string");
 const {DebuggerServer} = require("devtools/server/main");
 const Services = require("Services");
 const promise = require("promise");
 const {isWindowIncluded} = require("devtools/shared/layout/utils");
 const specs = require("devtools/shared/specs/storage");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyImporter(this, "OS", "resource://gre/modules/osfile.jsm");
 loader.lazyImporter(this, "Sqlite", "resource://gre/modules/Sqlite.jsm");
-loader.lazyImporter(this, "Task", "resource://gre/modules/Task.jsm", "Task");
 
 var gTrackedMessageManager = new Map();
 
 // Maximum number of cookies/local storage key-value-pairs that can be sent
 // over the wire to the client in one request.
 const MAX_STORE_OBJECT_COUNT = 50;
 // Delay for the batch job that sends the accumulated update packets to the
 // client (ms).

--- a/devtools/server/actors/styles.js
+++ b/devtools/server/actors/styles.js
@@ -5,17 +5,17 @@
 "use strict";
 
 const {Cc, Ci} = require("chrome");
 const promise = require("promise");
 const protocol = require("devtools/shared/protocol");
 const {LongStringActor} = require("devtools/server/actors/string");
 const {getDefinedGeometryProperties} = require("devtools/server/actors/highlighters/geometry-editor");
 const {parseDeclarations} = require("devtools/client/shared/css-parsing-utils");
-const {Task} = require("resource://gre/modules/Task.jsm");
+const {Task} = require("devtools/shared/task");
 const events = require("sdk/event/core");
 
 // This will also add the "stylesheet" actor type for protocol.js to recognize
 const {UPDATE_PRESERVING_RULES, UPDATE_GENERAL} = require("devtools/server/actors/stylesheets");
 const {pageStyleSpec, styleRuleSpec} = require("devtools/shared/specs/styles");
 
 loader.lazyRequireGetter(this, "CSS", "CSS");
 loader.lazyGetter(this, "CssLogic", () => require("devtools/shared/inspector/css-logic").CssLogic);

--- a/devtools/server/actors/stylesheets.js
+++ b/devtools/server/actors/stylesheets.js
@@ -5,19 +5,19 @@
 "use strict";
 
 var { components, Cc, Ci, Cu } = require("chrome");
 var Services = require("Services");
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 Cu.import("resource://gre/modules/FileUtils.jsm");
-Cu.import("resource://gre/modules/Task.jsm");
 
 const promise = require("promise");
+const {Task} = require("devtools/shared/task");
 const events = require("sdk/event/core");
 const protocol = require("devtools/shared/protocol");
 const {Arg, Option, method, RetVal, types} = protocol;
 const {LongStringActor, ShortLongString} = require("devtools/server/actors/string");
 const {fetch} = require("devtools/shared/DevToolsUtils");
 const {listenOnce} = require("devtools/shared/async-utils");
 const {originalSourceSpec, mediaRuleSpec, styleSheetSpec,
        styleSheetsSpec} = require("devtools/shared/specs/stylesheets");

--- a/devtools/server/performance/profiler.js
+++ b/devtools/server/performance/profiler.js
@@ -5,17 +5,17 @@
 
 const { Cc, Ci, Cu } = require("chrome");
 const Services = require("Services");
 const { Class } = require("sdk/core/heritage");
 loader.lazyRequireGetter(this, "events", "sdk/event/core");
 loader.lazyRequireGetter(this, "EventTarget", "sdk/event/target", true);
 loader.lazyRequireGetter(this, "DevToolsUtils", "devtools/shared/DevToolsUtils");
 loader.lazyRequireGetter(this, "DeferredTask", "resource://gre/modules/DeferredTask.jsm", true);
-loader.lazyRequireGetter(this, "Task", "resource://gre/modules/Task.jsm", true);
+loader.lazyRequireGetter(this, "Task", "devtools/shared/task", true);
 
 // Events piped from system observers to Profiler instances.
 const PROFILER_SYSTEM_EVENTS = [
   "console-api-profiler",
   "profiler-started",
   "profiler-stopped"
 ];
 

--- a/devtools/server/performance/recorder.js
+++ b/devtools/server/performance/recorder.js
@@ -1,15 +1,15 @@
 /* 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 { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "Services");
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "extend",
   "sdk/util/object", true);
 loader.lazyRequireGetter(this, "Class",
   "sdk/core/heritage", true);
 loader.lazyRequireGetter(this, "EventTarget",

--- a/devtools/server/performance/timeline.js
+++ b/devtools/server/performance/timeline.js
@@ -20,17 +20,17 @@
  *   timeline.on("markers", function(markers) {...})
  */
 
 const { Ci, Cu } = require("chrome");
 const { Class } = require("sdk/core/heritage");
 // Be aggressive about lazy loading, as this will run on every
 // toolbox startup
 loader.lazyRequireGetter(this, "events", "sdk/event/core");
-loader.lazyRequireGetter(this, "Task", "resource://gre/modules/Task.jsm", true);
+loader.lazyRequireGetter(this, "Task", "devtools/shared/task", true);
 loader.lazyRequireGetter(this, "Memory", "devtools/server/performance/memory", true);
 loader.lazyRequireGetter(this, "Framerate", "devtools/server/performance/framerate", true);
 loader.lazyRequireGetter(this, "StackFrameCache", "devtools/server/actors/utils/stack", true);
 loader.lazyRequireGetter(this, "EventTarget", "sdk/event/target", true);
 
 // How often do we pull markers from the docShells, and therefore, how often do
 // we send events to the front (knowing that when there are no markers in the
 // docShell, no event is sent).

--- a/devtools/server/tests/mochitest/director-helpers.js
+++ b/devtools/server/tests/mochitest/director-helpers.js
@@ -13,17 +13,17 @@ SimpleTest.registerCleanupFunction(funct
   Services.prefs.clearUserPref("dom.mozBrowserFramesEnabled");
 });
 
 const { DirectorRegistry,
         DirectorRegistryFront } = require("devtools/server/actors/director-registry");
 
 const { DirectorManagerFront } = require("devtools/server/actors/director-manager");
 
-const {Task} = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 /** *********************************
  *  director helpers functions
  **********************************/
 
 function* newConnectedDebuggerClient(opts) {
   var transport = DebuggerServer.connectPipe();
   var client = new DebuggerClient(transport);

--- a/devtools/server/tests/mochitest/inspector-helpers.js
+++ b/devtools/server/tests/mochitest/inspector-helpers.js
@@ -1,14 +1,14 @@
 var Cu = Components.utils;
 
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const {DebuggerClient} = require("devtools/shared/client/main");
 const {DebuggerServer} = require("devtools/server/main");
-Cu.import("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 const Services = require("Services");
 const promise = require("promise");
 const {_documentWalker} = require("devtools/server/actors/inspector");
 
 // Always log packets when running tests.
 Services.prefs.setBoolPref("devtools.debugger.log", true);
 SimpleTest.registerCleanupFunction(function () {

--- a/devtools/server/tests/mochitest/memory-helpers.js
+++ b/devtools/server/tests/mochitest/memory-helpers.js
@@ -1,14 +1,14 @@
 var Cu = Components.utils;
 var Cc = Components.classes;
 var Ci = Components.interfaces;
 
-Cu.import("resource://gre/modules/Task.jsm");
 var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { Task } = require("devtools/shared/task");
 var Services = require("Services");
 var { DebuggerClient } = require("devtools/shared/client/main");
 var { DebuggerServer } = require("devtools/server/main");
 
 var { MemoryFront } = require("devtools/server/actors/memory");
 
 // Always log packets when running tests.
 Services.prefs.setBoolPref("devtools.debugger.log", true);

--- a/devtools/server/tests/mochitest/memprof-helpers.js
+++ b/devtools/server/tests/mochitest/memprof-helpers.js
@@ -1,20 +1,20 @@
 var Cu = Components.utils;
 var Cc = Components.classes;
 var Ci = Components.interfaces;
 
-var { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
 var { require } =
   Cu.import("resource://devtools/shared/Loader.jsm", {});
 
 var Services = require("Services");
 var { DebuggerClient } = require("devtools/shared/client/main");
 var { DebuggerServer } = require("devtools/server/main");
 var { MemprofFront } = require("devtools/server/actors/memprof");
+var { Task } = require("devtools/shared/task");
 
 // Always log packets when running tests.
 Services.prefs.setBoolPref("devtools.debugger.log", true);
 SimpleTest.registerCleanupFunction(function () {
   Services.prefs.clearUserPref("devtools.debugger.log");
 });
 
 function startServerAndGetSelectedTabMemprof() {

--- a/devtools/server/tests/unit/head_dbg.js
+++ b/devtools/server/tests/unit/head_dbg.js
@@ -6,17 +6,17 @@ var Cc = Components.classes;
 var Ci = Components.interfaces;
 var Cu = Components.utils;
 var Cr = Components.results;
 var CC = Components.Constructor;
 
 const { require, loader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { worker } = Cu.import("resource://devtools/shared/worker/loader.js", {});
 const promise = require("promise");
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 
 const Services = require("Services");
 // Always log packets when running tests. runxpcshelltests.py will throw
 // the output away anyway, unless you give it the --verbose flag.
 Services.prefs.setBoolPref("devtools.debugger.log", true);
 // Enable remote debugging for the relevant tests.
 Services.prefs.setBoolPref("devtools.debugger.remote-enabled", true);
 

--- a/devtools/shared/async-utils.js
+++ b/devtools/shared/async-utils.js
@@ -9,17 +9,17 @@
  * run by Tasks. An async function returns a Promise for the resolution of the
  * function. When the function returns, the promise is resolved with the
  * returned value. If it throws the promise rejects with the thrown error.
  *
  * See Task documentation at https://developer.mozilla.org/en-US/docs/Mozilla/JavaScript_code_modules/Task.jsm.
  */
 
 var {Cu} = require("chrome");
-var {Task} = require("resource://gre/modules/Task.jsm");
+var {Task} = require("devtools/shared/task");
 var Promise = require("promise");
 
 /**
  * Create an async function that only executes once per instance of an object.
  * Once called on a given object, the same promise will be returned for any
  * future calls for that object.
  *
  * @param Function func

--- a/devtools/shared/client/connection-manager.js
+++ b/devtools/shared/client/connection-manager.js
@@ -7,19 +7,17 @@
 "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");
-
-DevToolsUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
+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");

--- a/devtools/shared/fronts/inspector.js
+++ b/devtools/shared/fronts/inspector.js
@@ -18,17 +18,17 @@ const {
 const { makeInfallible } = require("devtools/shared/DevToolsUtils");
 const {
   inspectorSpec,
   nodeSpec,
   nodeListSpec,
   walkerSpec
 } = require("devtools/shared/specs/inspector");
 const promise = require("promise");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { Class } = require("sdk/core/heritage");
 const events = require("sdk/event/core");
 const object = require("sdk/util/object");
 
 const HIDDEN_CLASS = "__fx-devtools-hide-shortcut__";
 
 /**
  * Convenience API for building a list of attribute modifications

--- a/devtools/shared/fronts/styles.js
+++ b/devtools/shared/fronts/styles.js
@@ -10,17 +10,17 @@ const {
   custom,
   preEvent
 } = require("devtools/shared/protocol");
 const {
   pageStyleSpec,
   styleRuleSpec
 } = require("devtools/shared/specs/styles");
 const promise = require("promise");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const { Class } = require("sdk/core/heritage");
 
 loader.lazyGetter(this, "RuleRewriter", () => {
   return require("devtools/client/shared/css-parsing-utils").RuleRewriter;
 });
 
 /**
  * PageStyleFront, the front object for the PageStyleActor

--- a/devtools/shared/fronts/stylesheets.js
+++ b/devtools/shared/fronts/stylesheets.js
@@ -10,17 +10,17 @@ const {
 } = require("devtools/shared/indentation");
 const {
   originalSourceSpec,
   mediaRuleSpec,
   styleSheetSpec,
   styleSheetsSpec
 } = require("devtools/shared/specs/stylesheets");
 const promise = require("promise");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 const events = require("sdk/event/core");
 
 /**
  * The client-side counterpart for an OriginalSourceActor.
  */
 const OriginalSourceFront = FrontClassWithSpec(originalSourceSpec, {
   initialize: function (client, form) {
     Front.prototype.initialize.call(this, client, form);

--- a/devtools/shared/gcli/commands/screenshot.js
+++ b/devtools/shared/gcli/commands/screenshot.js
@@ -5,19 +5,19 @@
 "use strict";
 
 const { Cc, Ci, Cr } = require("chrome");
 const l10n = require("gcli/l10n");
 const Services = require("Services");
 const { NetUtil } = require("resource://gre/modules/NetUtil.jsm");
 const { getRect } = require("devtools/shared/layout/utils");
 const promise = require("promise");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyImporter(this, "Downloads", "resource://gre/modules/Downloads.jsm");
-loader.lazyImporter(this, "Task", "resource://gre/modules/Task.jsm");
 loader.lazyImporter(this, "OS", "resource://gre/modules/osfile.jsm");
 loader.lazyImporter(this, "FileUtils", "resource://gre/modules/FileUtils.jsm");
 loader.lazyImporter(this, "PrivateBrowsingUtils",
                           "resource://gre/modules/PrivateBrowsingUtils.jsm");
 
 const BRAND_SHORT_NAME = Cc["@mozilla.org/intl/stringbundle;1"]
                            .getService(Ci.nsIStringBundleService)
                            .createBundle("chrome://branding/locale/brand.properties")

--- a/devtools/shared/gcli/source/lib/gcli/util/host.js
+++ b/devtools/shared/gcli/source/lib/gcli/util/host.js
@@ -15,17 +15,17 @@
  */
 
 'use strict';
 
 var Cc = require('chrome').Cc;
 var Ci = require('chrome').Ci;
 var URL = require('sdk/url').URL;
 
-var Task = require('resource://gre/modules/Task.jsm').Task;
+var { Task } = require("devtools/shared/task");
 
 var util = require('./util');
 
 function Highlighter(document) {
   this._document = document;
   this._nodes = util.createEmptyNodeList(this._document);
 }
 

--- a/devtools/shared/heapsnapshot/tests/unit/head_heapsnapshot.js
+++ b/devtools/shared/heapsnapshot/tests/unit/head_heapsnapshot.js
@@ -9,17 +9,17 @@ var Cu = Components.utils;
 var Cr = Components.results;
 var CC = Components.Constructor;
 
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { Match } = Cu.import("resource://test/Match.jsm", {});
 const { Census } = Cu.import("resource://test/Census.jsm", {});
 const { addDebuggerToGlobal } =
   Cu.import("resource://gre/modules/jsdebugger.jsm", {});
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const HeapAnalysesClient =
   require("devtools/shared/heapsnapshot/HeapAnalysesClient");
 const Services = require("Services");
 const { censusReportToCensusTreeNode } = require("devtools/shared/heapsnapshot/census-tree-node");
 const CensusUtils = require("devtools/shared/heapsnapshot/CensusUtils");
 const DominatorTreeNode = require("devtools/shared/heapsnapshot/DominatorTreeNode");

--- a/devtools/shared/moz.build
+++ b/devtools/shared/moz.build
@@ -48,10 +48,11 @@ DevToolsModules(
     'event-emitter.js',
     'event-parsers.js',
     'indentation.js',
     'Loader.jsm',
     'Parser.jsm',
     'path.js',
     'protocol.js',
     'system.js',
+    'task.js',
     'ThreadSafeDevToolsUtils.js',
 )

--- a/devtools/shared/qrcode/tests/mochitest/test_decode.html
+++ b/devtools/shared/qrcode/tests/mochitest/test_decode.html
@@ -8,17 +8,17 @@ Test decoding a simple message
   <title>Test decoding a simple message</title>
 
   <script type="application/javascript" src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css">
   <script type="application/javascript;version=1.8">
 window.onload = function() {
   const { utils: Cu } = Components;
   const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
-  const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+  const { Task } = require("devtools/shared/task");
   const promise = require("promise");
 
   const QR = require("devtools/shared/qrcode/index");
 
   SimpleTest.waitForExplicitFinish();
 
   const testImage =
     "data:image/gif;base64,R0lGODdhOgA6AIAAAAAAAP///ywAAAAAOgA6AAAC" +

--- a/devtools/shared/security/auth.js
+++ b/devtools/shared/security/auth.js
@@ -12,18 +12,17 @@ var promise = require("promise");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var { dumpn, dumpv } = DevToolsUtils;
 loader.lazyRequireGetter(this, "prompt",
   "devtools/shared/security/prompt");
 loader.lazyRequireGetter(this, "cert",
   "devtools/shared/security/cert");
 loader.lazyRequireGetter(this, "asyncStorage",
   "devtools/shared/async-storage");
-DevToolsUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 /**
  * A simple enum-like object with keys mirrored to values.
  * This makes comparison to a specfic value simpler without having to repeat and
  * mis-type the value.
  */
 function createEnum(obj) {
   for (let key in obj) {

--- a/devtools/shared/security/socket.js
+++ b/devtools/shared/security/socket.js
@@ -42,18 +42,17 @@ DevToolsUtils.defineLazyGetter(this, "ce
          .getService(Ci.nsICertOverrideService);
 });
 
 DevToolsUtils.defineLazyGetter(this, "nssErrorsService", () => {
   return Cc["@mozilla.org/nss_errors_service;1"]
          .getService(Ci.nsINSSErrorsService);
 });
 
-DevToolsUtils.defineLazyModuleGetter(this, "Task",
-  "resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 var DebuggerSocket = {};
 
 /**
  * Connects to a debugger server socket.
  *
  * @param host string
  *        The host name or IP address of the debugger server.

--- a/devtools/shared/security/tests/unit/head_dbg.js
+++ b/devtools/shared/security/tests/unit/head_dbg.js
@@ -6,17 +6,17 @@ var Cc = Components.classes;
 var Ci = Components.interfaces;
 var Cu = Components.utils;
 var Cr = Components.results;
 var CC = Components.Constructor;
 
 const { require } =
   Cu.import("resource://devtools/shared/Loader.jsm", {});
 const promise = require("promise");
-const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
+const { Task } = require("devtools/shared/task");
 
 const Services = require("Services");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const xpcInspector = require("xpcInspector");
 const { DebuggerServer } = require("devtools/server/main");
 const { DebuggerClient } = require("devtools/shared/client/main");
 
 // We do not want to log packets by default, because in some tests,

--- a/devtools/shared/system.js
+++ b/devtools/shared/system.js
@@ -1,15 +1,15 @@
 /* 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 } = require("chrome");
-const { Task } = require("resource://gre/modules/Task.jsm");
+const { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "Services");
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "OS", "resource://gre/modules/commonjs/node/os.js");
 loader.lazyRequireGetter(this, "DebuggerServer", "devtools/server/main", true);
 loader.lazyRequireGetter(this, "AppConstants",
   "resource://gre/modules/AppConstants.jsm", true);
 loader.lazyGetter(this, "screenManager", () => {

copy from toolkit/modules/Task.jsm
copy to devtools/shared/task.js
--- a/toolkit/modules/Task.jsm
+++ b/devtools/shared/task.js
@@ -1,39 +1,40 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
 /* 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";
 
-this.EXPORTED_SYMBOLS = [
-  "Task"
-];
+/* eslint-disable spaced-comment */
+/* globals StopIteration */
 
 /**
  * This module implements a subset of "Task.js" <http://taskjs.org/>.
+ * It is a copy of toolkit/modules/Task.jsm.  Please try not to
+ * diverge the API here.
  *
  * Paraphrasing from the Task.js site, tasks make sequential, asynchronous
  * operations simple, using the power of JavaScript's "yield" operator.
  *
  * Tasks are built upon generator functions and promises, documented here:
  *
  * <https://developer.mozilla.org/en/JavaScript/Guide/Iterators_and_Generators>
  * <http://wiki.commonjs.org/wiki/Promises/A>
  *
  * The "Task.spawn" function takes a generator function and starts running it as
  * a task.  Every time the task yields a promise, it waits until the promise is
  * fulfilled.  "Task.spawn" returns a promise that is resolved when the task
  * completes successfully, or is rejected if an exception occurs.
  *
  * -----------------------------------------------------------------------------
  *
- * Cu.import("resource://gre/modules/Task.jsm");
+ * const {Task} = require("devtools/shared/task");
  *
  * Task.spawn(function* () {
  *
  *   // This is our task. Let's create a promise object, wait on it and capture
  *   // its resolution value.
  *   let myPromise = getPromiseResolvedOnTimeoutWithValue(1000, "Value");
  *   let result = yield myPromise;
  *
@@ -81,43 +82,34 @@ this.EXPORTED_SYMBOLS = [
  *   spawn a task from it, regardless of whether it is an asynchronous generator
  *   or a synchronous function.  This comes in handy when iterating over
  *   function lists where some items have been converted to tasks and some not.
  */
 
 ////////////////////////////////////////////////////////////////////////////////
 //// Globals
 
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const Cu = Components.utils;
-const Cr = Components.results;
-
-// For now, we're worried about add-ons using Tasks with CPOWs, so we'll
-// permit them in this scope, but this support will go away soon.
-Cu.permitCPOWsInScope(this);
-
-Cu.import("resource://gre/modules/Promise.jsm");
+const Promise = require("promise");
 
 // The following error types are considered programmer errors, which should be
 // reported (possibly redundantly) so as to let programmers fix their code.
-const ERRORS_TO_REPORT = ["EvalError", "RangeError", "ReferenceError", "TypeError"];
+const ERRORS_TO_REPORT = ["EvalError", "RangeError", "ReferenceError",
+                          "TypeError"];
 
 /**
  * The Task currently being executed
  */
 var gCurrentTask = null;
 
 /**
  * If `true`, capture stacks whenever entering a Task and rewrite the
  * stack any exception thrown through a Task.
  */
 var gMaintainStack = false;
 
-
 /**
  * Iterate through the lines of a string.
  *
  * @return Iterator<string>
  */
 function* linesOf(string) {
   let reLine = /([^\r\n])+/g;
   let match;
@@ -128,49 +120,49 @@ function* linesOf(string) {
 
 /**
  * Detect whether a value is a generator.
  *
  * @param aValue
  *        The value to identify.
  * @return A boolean indicating whether the value is a generator.
  */
-function isGenerator(aValue) {
-  return Object.prototype.toString.call(aValue) == "[object Generator]";
+function isGenerator(value) {
+  return Object.prototype.toString.call(value) == "[object Generator]";
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 //// Task
 
 /**
  * This object provides the public module functions.
  */
 this.Task = {
   /**
    * Creates and starts a new task.
    *
-   * @param aTask
+   * @param task
    *        - If you specify a generator function, it is called with no
    *          arguments to retrieve the associated iterator.  The generator
    *          function is a task, that is can yield promise objects to wait
    *          upon.
    *        - If you specify the iterator returned by a generator function you
    *          called, the generator function is also executed as a task.  This
    *          allows you to call the function with arguments.
    *        - If you specify a function that is not a generator, it is called
    *          with no arguments, and its return value is used to resolve the
    *          returned promise.
    *        - If you specify anything else, you get a promise that is already
    *          resolved with the specified value.
    *
    * @return A promise object where you can register completion callbacks to be
    *         called when the task terminates.
    */
-  spawn: function Task_spawn(aTask) {
-    return createAsyncFunction(aTask).call(undefined);
+  spawn: function (task) {
+    return createAsyncFunction(task).call(undefined);
   },
 
   /**
    * Create and return an 'async function' that starts a new task.
    *
    * This is similar to 'spawn' except that it doesn't immediately start
    * the task, it binds the task to the async function's 'this' object and
    * arguments, and it requires the task to be a function.
@@ -196,56 +188,56 @@ this.Task = {
    *     return yield sendGreeting(this.message.replace(/NAME/, name));
    *   })
    * };
    *
    * While maintaining identical semantics:
    *
    * greeter.greet("Mitchell").then((reply) => { ... }); // behaves the same
    *
-   * @param aTask
+   * @param task
    *        The task function to start.
    *
    * @return A function that starts the task function and returns its promise.
    */
-  async: function Task_async(aTask) {
-    if (typeof(aTask) != "function") {
-      throw new TypeError("aTask argument must be a function");
+  async: function (task) {
+    if (typeof (task) != "function") {
+      throw new TypeError("task argument must be a function");
     }
 
-    return createAsyncFunction(aTask);
+    return createAsyncFunction(task);
   },
 
   /**
    * Constructs a special exception that, when thrown inside a legacy generator
    * function (non-star generator), allows the associated task to be resolved
    * with a specific value.
    *
    * Example: throw new Task.Result("Value");
    */
-  Result: function Task_Result(aValue) {
-    this.value = aValue;
+  Result: function (value) {
+    this.value = value;
   }
 };
 
-function createAsyncFunction(aTask) {
+function createAsyncFunction(task) {
   let asyncFunction = function () {
-    let result = aTask;
-    if (aTask && typeof(aTask) == "function") {
-      if (aTask.isAsyncFunction) {
+    let result = task;
+    if (task && typeof (task) == "function") {
+      if (task.isAsyncFunction) {
         throw new TypeError(
           "Cannot use an async function in place of a promise. " +
           "You should either invoke the async function first " +
           "or use 'Task.spawn' instead of 'Task.async' to start " +
           "the Task and return its promise.");
       }
 
       try {
         // Let's call into the function ourselves.
-        result = aTask.apply(this, arguments);
+        result = task.apply(this, arguments);
       } catch (ex) {
         if (ex instanceof Task.Result) {
           return Promise.resolve(ex.value);
         }
         return Promise.reject(ex);
       }
     }
 
@@ -295,55 +287,54 @@ TaskImpl.prototype = {
   /**
    * Whether this Task is using a star generator.
    */
   _isStarGenerator: false,
 
   /**
    * Main execution routine, that calls into the generator function.
    *
-   * @param aSendResolved
+   * @param sendResolved
    *        If true, indicates that we should continue into the generator
    *        function regularly (if we were waiting on a promise, it was
    *        resolved). If true, indicates that we should cause an exception to
    *        be thrown into the generator function (if we were waiting on a
    *        promise, it was rejected).
-   * @param aSendValue
+   * @param sendValue
    *        Resolution result or rejection exception, if any.
    */
-  _run: function TaskImpl_run(aSendResolved, aSendValue) {
-
+  _run: function (sendResolved, sendValue) {
     try {
       gCurrentTask = this;
 
       if (this._isStarGenerator) {
         try {
-          let result = aSendResolved ? this._iterator.next(aSendValue)
-                                     : this._iterator.throw(aSendValue);
+          let result = sendResolved ? this._iterator.next(sendValue)
+                                    : this._iterator.throw(sendValue);
 
           if (result.done) {
             // The generator function returned.
             this.deferred.resolve(result.value);
           } else {
             // The generator function yielded.
             this._handleResultValue(result.value);
           }
         } catch (ex) {
           // The generator function failed with an uncaught exception.
           this._handleException(ex);
         }
       } else {
         try {
-          let yielded = aSendResolved ? this._iterator.send(aSendValue)
-                                      : this._iterator.throw(aSendValue);
+          let yielded = sendResolved ? this._iterator.send(sendValue)
+                                     : this._iterator.throw(sendValue);
           this._handleResultValue(yielded);
         } catch (ex) {
           if (ex instanceof Task.Result) {
-            // The generator function threw the special exception that allows it to
-            // return a specific value on resolution.
+            // The generator function threw the special exception that
+            // allows it to return a specific value on resolution.
             this.deferred.resolve(ex.value);
           } else if (ex instanceof StopIteration) {
             // The generator function terminated with no specific result.
             this.deferred.resolve(undefined);
           } else {
             // The generator function failed with an uncaught exception.
             this._handleException(ex);
           }
@@ -372,107 +363,101 @@ TaskImpl.prototype = {
         gCurrentTask = null;
       }
     }
   },
 
   /**
    * Handle a value yielded by a generator.
    *
-   * @param aValue
+   * @param value
    *        The yielded value to handle.
    */
-  _handleResultValue: function TaskImpl_handleResultValue(aValue) {
+  _handleResultValue: function (value) {
     // If our task yielded an iterator resulting from calling another
     // generator function, automatically spawn a task from it, effectively
     // turning it into a promise that is fulfilled on task completion.
-    if (isGenerator(aValue)) {
-      aValue = Task.spawn(aValue);
+    if (isGenerator(value)) {
+      value = Task.spawn(value);
     }
 
-    if (aValue && typeof(aValue.then) == "function") {
+    if (value && typeof (value.then) == "function") {
       // We have a promise object now. When fulfilled, call again into this
       // function to continue the task, with either a resolution or rejection
       // condition.
-      aValue.then(this._run.bind(this, true),
+      value.then(this._run.bind(this, true),
                   this._run.bind(this, false));
     } else {
       // If our task yielded a value that is not a promise, just continue and
       // pass it directly as the result of the yield statement.
-      this._run(true, aValue);
+      this._run(true, value);
     }
   },
 
   /**
    * Handle an uncaught exception thrown from a generator.
    *
-   * @param aException
+   * @param exception
    *        The uncaught exception to handle.
    */
-  _handleException: function TaskImpl_handleException(aException) {
-
+  _handleException: function (exception) {
     gCurrentTask = this;
 
-    if (aException && typeof aException == "object" && "stack" in aException) {
-
-      let stack = aException.stack;
+    if (exception && typeof exception == "object" && "stack" in exception) {
+      let stack = exception.stack;
 
       if (gMaintainStack &&
-          aException._capturedTaskStack != this._stack &&
+          exception._capturedTaskStack != this._stack &&
           typeof stack == "string") {
-
         // Rewrite the stack for more readability.
 
         let bottomStack = this._stack;
-        let topStack = stack;
 
         stack = Task.Debugging.generateReadableStack(stack);
 
-        aException.stack = stack;
+        exception.stack = stack;
 
-        // If aException is reinjected in the same task and rethrown,
+        // If exception is reinjected in the same task and rethrown,
         // we don't want to perform the rewrite again.
-        aException._capturedTaskStack = bottomStack;
+        exception._capturedTaskStack = bottomStack;
       } else if (!stack) {
         stack = "Not available";
       }
 
-      if ("name" in aException &&
-          ERRORS_TO_REPORT.indexOf(aException.name) != -1) {
-
+      if ("name" in exception &&
+          ERRORS_TO_REPORT.indexOf(exception.name) != -1) {
         // We suspect that the exception is a programmer error, so we now
         // display it using dump().  Note that we do not use Cu.reportError as
         // we assume that this is a programming error, so we do not want end
         // users to see it. Also, if the programmer handles errors correctly,
         // they will either treat the error or log them somewhere.
 
         dump("*************************\n");
         dump("A coding exception was thrown and uncaught in a Task.\n\n");
-        dump("Full message: " + aException + "\n");
-        dump("Full stack: " + aException.stack + "\n");
+        dump("Full message: " + exception + "\n");
+        dump("Full stack: " + exception.stack + "\n");
         dump("*************************\n");
       }
     }
 
-    this.deferred.reject(aException);
+    this.deferred.reject(exception);
   },
 
   get callerStack() {
     // Cut `this._stack` at the last line of the first block that
-    // contains Task.jsm, keep the tail.
+    // contains task.js, keep the tail.
     for (let [line, index] of linesOf(this._stack || "")) {
-      if (line.indexOf("/Task.jsm:") == -1) {
+      if (line.indexOf("/task.js:") == -1) {
         return this._stack.substring(index);
       }
     }
     return "";
   }
 };
 
-
 Task.Debugging = {
 
   /**
    * Control stack rewriting.
    *
    * If `true`, any exception thrown from a Task will be rewritten to
    * provide a human-readable stack trace. Otherwise, stack traces will
    * be left unchanged.
@@ -485,42 +470,45 @@ Task.Debugging = {
    */
   get maintainStack() {
     return gMaintainStack;
   },
   set maintainStack(x) {
     if (!x) {
       gCurrentTask = null;
     }
-    return gMaintainStack = x;
+    gMaintainStack = x;
+    return x;
   },
 
   /**
    * Generate a human-readable stack for an error raised in
    * a Task.
    *
    * @param {string} topStack The stack provided by the error.
    * @param {string=} prefix Optionally, a prefix for each line.
    */
-  generateReadableStack: function(topStack, prefix = "") {
+  generateReadableStack: function (topStack, prefix = "") {
     if (!gCurrentTask) {
       return topStack;
     }
 
-    // Cut `topStack` at the first line that contains Task.jsm, keep the head.
+    // Cut `topStack` at the first line that contains task.js, keep the head.
     let lines = [];
     for (let [line] of linesOf(topStack)) {
-      if (line.indexOf("/Task.jsm:") != -1) {
+      if (line.indexOf("/task.js:") != -1) {
         break;
       }
       lines.push(prefix + line);
     }
     if (!prefix) {
       lines.push(gCurrentTask.callerStack);
     } else {
       for (let [line] of linesOf(gCurrentTask.callerStack)) {
         lines.push(prefix + line);
       }
     }
 
     return lines.join("\n");
   }
 };
+
+exports.Task = Task;