--- a/devtools/client/animationinspector/animation-controller.js
+++ b/devtools/client/animationinspector/animation-controller.js
@@ -13,17 +13,17 @@
 "use strict";
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 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, "EventEmitter", "devtools/shared/old-event-emitter");
 loader.lazyRequireGetter(this, "AnimationsFront", "devtools/shared/fronts/animation", true);
 
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const L10N =
       new LocalizationHelper("devtools/client/locales/animationinspector.properties");
 
 // Global toolbox/inspector, set when startup is called.
 var gToolbox, gInspector;

--- a/devtools/client/animationinspector/components/animation-details.js
+++ b/devtools/client/animationinspector/components/animation-details.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 {Task} = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {createNode, getCssPropertyName} =
   require("devtools/client/animationinspector/utils");
 const {Keyframes} = require("devtools/client/animationinspector/components/keyframes");
 
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const L10N =
   new LocalizationHelper("devtools/client/locales/animationinspector.properties");
 

--- a/devtools/client/animationinspector/components/animation-target-node.js
+++ b/devtools/client/animationinspector/components/animation-target-node.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 {Task} = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-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();
 
 /**
  * UI component responsible for displaying a preview of the target dom node of

--- a/devtools/client/animationinspector/components/animation-time-block.js
+++ b/devtools/client/animationinspector/components/animation-time-block.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {createNode, createSVGNode, TimeScale, getFormattedAnimationTitle} =
   require("devtools/client/animationinspector/utils");
 const {SummaryGraphHelper, getPreferredKeyframesProgressThreshold,
        getPreferredProgressThreshold} =
   require("devtools/client/animationinspector/graph-helper");
 
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const L10N =

--- a/devtools/client/animationinspector/components/animation-timeline.js
+++ b/devtools/client/animationinspector/components/animation-timeline.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 {Task} = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {
   createNode,
   findOptimalTimeInterval,
   getFormattedAnimationTitle,
   TimeScale,
   getCssPropertyName
 } = require("devtools/client/animationinspector/utils");
 const {AnimationDetails} = require("devtools/client/animationinspector/components/animation-details");

--- a/devtools/client/animationinspector/components/keyframes.js
+++ b/devtools/client/animationinspector/components/keyframes.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {createNode, createSVGNode} =
   require("devtools/client/animationinspector/utils");
 const {ProgressGraphHelper, getPreferredKeyframesProgressThreshold} =
          require("devtools/client/animationinspector/graph-helper.js");
 
 // Counter for linearGradient ID.
 let LINEAR_GRADIENT_ID_COUNTER = 0;
 

--- a/devtools/client/animationinspector/components/rate-selector.js
+++ b/devtools/client/animationinspector/components/rate-selector.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {createNode} = require("devtools/client/animationinspector/utils");
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const L10N =
       new LocalizationHelper("devtools/client/locales/animationinspector.properties");
 
 // List of playback rate presets displayed in the timeline toolbar.
 const PLAYBACK_RATES = [.1, .25, .5, 1, 2, 5, 10];
 

--- a/devtools/client/animationinspector/utils.js
+++ b/devtools/client/animationinspector/utils.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";
 
-loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
+loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/old-event-emitter");
 
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const L10N =
       new LocalizationHelper("devtools/client/locales/animationinspector.properties");
 
 // How many times, maximum, can we loop before we find the optimal time
 // interval in the timeline graph.
 const OPTIMAL_TIME_INTERVAL_MAX_ITERS = 100;

--- a/devtools/client/canvasdebugger/canvasdebugger.js
+++ b/devtools/client/canvasdebugger/canvasdebugger.js
@@ -5,17 +5,17 @@
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 const { SideMenuWidget } = require("resource://devtools/client/shared/widgets/SideMenuWidget.jsm");
 const promise = require("promise");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { CallWatcherFront } = require("devtools/shared/fronts/call-watcher");
 const { CanvasFront } = require("devtools/shared/fronts/canvas");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const flags = require("devtools/shared/flags");
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const { PluralForm } = require("devtools/shared/plural-form");
 const { Heritage, WidgetMethods, setNamedTimeout, clearNamedTimeout,
         setConditionalTimeout } = require("devtools/client/shared/widgets/view-helpers");

--- a/devtools/client/canvasdebugger/panel.js
+++ b/devtools/client/canvasdebugger/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 { Cc, Ci, Cu, Cr } = require("chrome");
 const promise = require("promise");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { CanvasFront } = require("devtools/shared/fronts/canvas");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 
 function CanvasDebuggerPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;
   this._destroyer = null;
 

--- a/devtools/client/debugger/debugger-controller.js
+++ b/devtools/client/debugger/debugger-controller.js
@@ -103,17 +103,17 @@ const { require } = BrowserLoader({
 });
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 XPCOMUtils.defineConstant(this, "require", require);
 const { SimpleListWidget } = require("resource://devtools/client/shared/widgets/SimpleListWidget.jsm");
 const { BreadcrumbsWidget } = require("resource://devtools/client/shared/widgets/BreadcrumbsWidget.jsm");
 const { SideMenuWidget } = require("resource://devtools/client/shared/widgets/SideMenuWidget.jsm");
 const { VariablesView } = require("resource://devtools/client/shared/widgets/VariablesView.jsm");
 const { VariablesViewController, StackFrameUtils } = require("resource://devtools/client/shared/widgets/VariablesViewController.jsm");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { gDevTools } = require("devtools/client/framework/devtools");
 const { ViewHelpers, Heritage, WidgetMethods, setNamedTimeout,
         clearNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 
 // React
 const React = 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/debugger/panel.js
+++ b/devtools/client/debugger/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 { Cc, Ci, Cu, Cr } = require("chrome");
 const promise = require("promise");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 
 function DebuggerPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;
   this._destroyer = null;
 
   this._view = this.panelWin.DebuggerView;

--- a/devtools/client/debugger/test/mochitest/head.js
+++ b/devtools/client/debugger/test/mochitest/head.js
@@ -13,17 +13,17 @@ Services.scriptloader.loadSubScript("chr
 // be affected by this pref.
 var gEnableLogging = Services.prefs.getBoolPref("devtools.debugger.log");
 Services.prefs.setBoolPref("devtools.debugger.log", false);
 
 var { BrowserToolboxProcess } = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
 var { DebuggerServer } = require("devtools/server/main");
 var { DebuggerClient, ObjectClient } = require("devtools/shared/client/main");
 var { AddonManager } = Cu.import("resource://gre/modules/AddonManager.jsm", {});
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 var { Toolbox } = require("devtools/client/framework/toolbox");
 
 const chromeRegistry = Cc["@mozilla.org/chrome/chrome-registry;1"].getService(Ci.nsIChromeRegistry);
 
 // Override promise with deprecated-sync-thenables
 promise = Cu.import("resource://devtools/shared/deprecated-sync-thenables.js", {}).Promise;
 
 const EXAMPLE_URL = "http://example.com/browser/devtools/client/debugger/test/mochitest/";

--- a/devtools/client/dom/dom-panel.js
+++ b/devtools/client/dom/dom-panel.js
@@ -5,17 +5,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
 const { Cu } = require("chrome");
 const defer = require("devtools/shared/defer");
 const { ObjectClient } = require("devtools/shared/client/main");
 
 const promise = require("promise");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 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;

--- a/devtools/client/framework/ToolboxProcess.jsm
+++ b/devtools/client/framework/ToolboxProcess.jsm
@@ -14,17 +14,17 @@ const CHROME_DEBUGGER_PROFILE_NAME = "ch
 const { require, DevToolsLoader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "Subprocess", "resource://gre/modules/Subprocess.jsm");
 XPCOMUtils.defineLazyGetter(this, "Telemetry", function () {
   return require("devtools/client/shared/telemetry");
 });
 XPCOMUtils.defineLazyGetter(this, "EventEmitter", function () {
-  return require("devtools/shared/event-emitter");
+  return require("devtools/shared/old-event-emitter");
 });
 const promise = require("promise");
 const Services = require("Services");
 
 this.EXPORTED_SYMBOLS = ["BrowserToolboxProcess"];
 
 var processes = new Set();
 

--- a/devtools/client/framework/devtools.js
+++ b/devtools/client/framework/devtools.js
@@ -18,17 +18,17 @@ loader.lazyImporter(this, "ScratchpadMan
 
 // Dependencies required for addon sdk compatibility layer.
 loader.lazyRequireGetter(this, "DebuggerServer", "devtools/server/main", true);
 loader.lazyRequireGetter(this, "DebuggerClient", "devtools/shared/client/main", true);
 loader.lazyImporter(this, "BrowserToolboxProcess", "resource://devtools/client/framework/ToolboxProcess.jsm");
 
 const {defaultTools: DefaultTools, defaultThemes: DefaultThemes} =
   require("devtools/client/definitions");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const AboutDevTools = require("devtools/client/framework/about-devtools-toolbox");
 const {Task} = require("devtools/shared/task");
 const {getTheme, setTheme, addThemeObserver, removeThemeObserver} =
   require("devtools/client/shared/theme");
 
 const FORBIDDEN_IDS = new Set(["toolbox", ""]);
 const MAX_ORDINAL = 99;
 

--- a/devtools/client/framework/menu.js
+++ b/devtools/client/framework/menu.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 /**
  * A partial implementation of the Menu API provided by electron:
  * https://github.com/electron/electron/blob/master/docs/api/menu.md.
  *
  * Extra features:
  *  - Emits an 'open' and 'close' event when the menu is opened/closed
 

--- a/devtools/client/framework/selection.js
+++ b/devtools/client/framework/selection.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 nodeConstants = require("devtools/shared/dom-node-constants");
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 
 /**
  * API
  *
  *   new Selection(walker=null)
  *   destroy()
  *   node (readonly)
  *   setNode(node, origin="unknown")

--- a/devtools/client/framework/sidebar.js
+++ b/devtools/client/framework/sidebar.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 Services = require("Services");
 var {Task} = require("devtools/shared/task");
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 var Telemetry = require("devtools/client/shared/telemetry");
 
 const {LocalizationHelper} = require("devtools/shared/l10n");
 const L10N = new LocalizationHelper("devtools/client/locales/toolbox.properties");
 
 const XULNS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 /**

--- a/devtools/client/framework/target.js
+++ b/devtools/client/framework/target.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 { Ci } = require("chrome");
 const defer = require("devtools/shared/defer");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const Services = require("Services");
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 
 loader.lazyRequireGetter(this, "DebuggerServer", "devtools/server/main", true);
 loader.lazyRequireGetter(this, "DebuggerClient",
   "devtools/shared/client/main", true);
 loader.lazyRequireGetter(this, "gDevTools",
   "devtools/client/framework/devtools", true);

--- a/devtools/client/framework/test/head.js
+++ b/devtools/client/framework/test/head.js
@@ -3,17 +3,17 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /* import-globals-from shared-head.js */
 
 // shared-head.js handles imports, constants, and utility functions
 Services.scriptloader.loadSubScript("chrome://mochitests/content/browser/devtools/client/framework/test/shared-head.js", this);
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 function toggleAllTools(state) {
   for (let [, tool] of gDevTools._tools) {
     if (!tool.visibilityswitch) {
       continue;
     }
     if (state) {
       Services.prefs.setBoolPref(tool.visibilityswitch, true);

--- a/devtools/client/framework/toolbox-hosts.js
+++ b/devtools/client/framework/toolbox-hosts.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const promise = require("promise");
 const defer = require("devtools/shared/defer");
 const Services = require("Services");
 const {DOMHelpers} = require("resource://devtools/client/shared/DOMHelpers.jsm");
 
 loader.lazyRequireGetter(this, "system", "devtools/shared/system");
 loader.lazyRequireGetter(this, "gDevToolsBrowser", "devtools/client/framework/devtools-browser", true);
 

--- a/devtools/client/framework/toolbox-options.js
+++ b/devtools/client/framework/toolbox-options.js
@@ -66,17 +66,17 @@ function OptionsPanel(iframeWindow, tool
   this._themeRegistered = this._themeRegistered.bind(this);
   this._themeUnregistered = this._themeUnregistered.bind(this);
   this._disableJSClicked = this._disableJSClicked.bind(this);
 
   this.disableJSNode = this.panelDoc.getElementById("devtools-disable-javascript");
 
   this._addListeners();
 
-  const EventEmitter = require("devtools/shared/event-emitter");
+  const EventEmitter = require("devtools/shared/old-event-emitter");
   EventEmitter.decorate(this);
 }
 
 OptionsPanel.prototype = {
 
   get target() {
     return this.toolbox.target;
   },

--- a/devtools/client/framework/toolbox.js
+++ b/devtools/client/framework/toolbox.js
@@ -15,17 +15,17 @@ const SCREENSIZE_HISTOGRAM = "DEVTOOLS_S
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 
 var {Ci, Cu, Cc} = require("chrome");
 var promise = require("promise");
 var defer = require("devtools/shared/defer");
 var Services = require("Services");
 var {Task} = require("devtools/shared/task");
 var {gDevTools} = require("devtools/client/framework/devtools");
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 var Telemetry = require("devtools/client/shared/telemetry");
 var { attachThread, detachThread } = require("./attach-thread");
 var Menu = require("devtools/client/framework/menu");
 var MenuItem = require("devtools/client/framework/menu-item");
 var { DOMHelpers } = require("resource://devtools/client/shared/DOMHelpers.jsm");
 const { KeyCodes } = require("devtools/client/shared/keycodes");
 var Startup = Cc["@mozilla.org/devtools/startup-clh;1"].getService(Ci.nsISupports)
   .wrappedJSObject;

--- a/devtools/client/inspector/breadcrumbs.js
+++ b/devtools/client/inspector/breadcrumbs.js
@@ -10,17 +10,17 @@ const promise = require("promise");
 
 const {ELLIPSIS} = require("devtools/shared/l10n");
 
 const MAX_LABEL_LENGTH = 40;
 
 const NS_XHTML = "http://www.w3.org/1999/xhtml";
 const SCROLL_REPEAT_MS = 100;
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 
 // Some margin may be required for visible element detection.
 const SCROLL_MARGIN = 1;
 
 /**
  * Component to replicate functionality of XUL arrowscrollbox
  * for breadcrumbs

--- a/devtools/client/inspector/inspector-search.js
+++ b/devtools/client/inspector/inspector-search.js
@@ -3,17 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const promise = require("promise");
 const {Task} = require("devtools/shared/task");
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const AutocompletePopup = require("devtools/client/shared/autocomplete-popup");
 const Services = require("Services");
 
 // Maximum number of selector suggestions shown in the panel.
 const MAX_SUGGESTIONS = 15;
 
 /**
  * Converts any input field into a document search box.

--- a/devtools/client/inspector/inspector.js
+++ b/devtools/client/inspector/inspector.js
@@ -6,17 +6,17 @@
 
 /* global window, BrowserLoader */
 
 "use strict";
 
 var Services = require("Services");
 var promise = require("promise");
 var defer = require("devtools/shared/defer");
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 const {executeSoon} = require("devtools/shared/DevToolsUtils");
 var KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 var {Task} = require("devtools/shared/task");
 const {initCssProperties} = require("devtools/shared/fronts/css-properties");
 const nodeConstants = require("devtools/shared/dom-node-constants");
 const Telemetry = require("devtools/client/shared/telemetry");
 
 const Menu = require("devtools/client/framework/menu");

--- a/devtools/client/inspector/markup/markup.js
+++ b/devtools/client/inspector/markup/markup.js
@@ -5,17 +5,17 @@
 "use strict";
 
 const promise = require("promise");
 const Services = require("Services");
 const defer = require("devtools/shared/defer");
 const {Task} = require("devtools/shared/task");
 const nodeConstants = require("devtools/shared/dom-node-constants");
 const nodeFilterConstants = require("devtools/shared/dom-node-filter-constants");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {LocalizationHelper} = require("devtools/shared/l10n");
 const {PluralForm} = require("devtools/shared/plural-form");
 const AutocompletePopup = require("devtools/client/shared/autocomplete-popup");
 const KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 const {scrollIntoViewIfNeeded} = require("devtools/client/shared/scroll");
 const {UndoStack} = require("devtools/client/shared/undo");
 const {HTMLTooltip} = require("devtools/client/shared/widgets/tooltip/HTMLTooltip");
 const {PrefObserver} = require("devtools/client/shared/prefs");

--- a/devtools/client/inspector/markup/views/html-editor.js
+++ b/devtools/client/inspector/markup/views/html-editor.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 Editor = require("devtools/client/sourceeditor/editor");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 /**
  * A wrapper around the Editor component, that allows editing of HTML.
  *
  * The main functionality this provides around the Editor is the ability
  * to show/hide/position an editor inplace. It only appends once to the
  * body, and uses CSS to position the editor.  The reason it is done this
  * way is that the editor is loaded in an iframe, and calling appendChild

--- a/devtools/client/inspector/rules/rules.js
+++ b/devtools/client/inspector/rules/rules.js
@@ -26,17 +26,17 @@ const {
   VIEW_NODE_VALUE_TYPE,
   VIEW_NODE_IMAGE_URL_TYPE,
   VIEW_NODE_LOCATION_TYPE,
   VIEW_NODE_SHAPE_POINT_TYPE,
 } = require("devtools/client/inspector/shared/node-types");
 const StyleInspectorMenu = require("devtools/client/inspector/shared/style-inspector-menu");
 const TooltipsOverlay = require("devtools/client/inspector/shared/tooltips-overlay");
 const {createChild, promiseWarn, debounce} = require("devtools/client/inspector/shared/utils");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 const clipboardHelper = require("devtools/shared/platform/clipboard");
 const AutocompletePopup = require("devtools/client/shared/autocomplete-popup");
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const PREF_UA_STYLES = "devtools.inspector.showUserAgentStyles";
 const PREF_DEFAULT_COLOR_UNIT = "devtools.defaultColorUnit";
 const PREF_ENABLE_MDN_DOCS_TOOLTIP =

--- a/devtools/client/inspector/rules/views/class-list-previewer.js
+++ b/devtools/client/inspector/rules/views/class-list-previewer.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {LocalizationHelper} = require("devtools/shared/l10n");
 
 const L10N = new LocalizationHelper("devtools/client/locales/inspector.properties");
 
 // This serves as a local cache for the classes applied to each of the node we care about
 // here.
 // The map is indexed by NodeFront. Any time a new node is selected in the inspector, an
 // entry is added here, indexed by the corresponding NodeFront.

--- a/devtools/client/inspector/rules/views/rule-editor.js
+++ b/devtools/client/inspector/rules/views/rule-editor.js
@@ -20,17 +20,17 @@ const {
   parseNamedDeclarations,
   parsePseudoClassesAndAttributes,
   SELECTOR_ATTRIBUTE,
   SELECTOR_ELEMENT,
   SELECTOR_PSEUDO_CLASS
 } = require("devtools/shared/css/parsing-utils");
 const promise = require("promise");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {Task} = require("devtools/shared/task");
 
 const STYLE_INSPECTOR_PROPERTIES = "devtools/shared/locales/styleinspector.properties";
 const {LocalizationHelper} = require("devtools/shared/l10n");
 const STYLE_INSPECTOR_L10N = new LocalizationHelper(STYLE_INSPECTOR_PROPERTIES);
 
 const PREF_ORIG_SOURCES = "devtools.styleeditor.source-maps-enabled";
 

--- a/devtools/client/inspector/shared/dom-node-preview.js
+++ b/devtools/client/inspector/shared/dom-node-preview.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("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {createNode} = require("devtools/client/animationinspector/utils");
 const { LocalizationHelper } = require("devtools/shared/l10n");
 
 const STRINGS_URI = "devtools/client/locales/inspector.properties";
 const L10N = new LocalizationHelper(STRINGS_URI);
 
 /**
  * UI component responsible for displaying a preview of a dom node.

--- a/devtools/client/inspector/shared/highlighters-overlay.js
+++ b/devtools/client/inspector/shared/highlighters-overlay.js
@@ -3,17 +3,17 @@
 /* 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 Services = require("Services");
 const {Task} = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {
   VIEW_NODE_VALUE_TYPE,
   VIEW_NODE_SHAPE_POINT_TYPE
 } = require("devtools/client/inspector/shared/node-types");
 
 const DEFAULT_GRID_COLOR = "#4B0082";
 const INSET_POINT_TYPES = ["top", "right", "bottom", "left"];
 

--- a/devtools/client/inspector/toolsidebar.js
+++ b/devtools/client/inspector/toolsidebar.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";
 
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 var Telemetry = require("devtools/client/shared/telemetry");
 var { Task } = require("devtools/shared/task");
 
 /**
  * This object represents replacement for ToolSidebar
  * implemented in devtools/client/framework/sidebar.js module
  *
  * This new component is part of devtools.html aimed at

--- a/devtools/client/memory/components/tree-map/canvas-utils.js
+++ b/devtools/client/memory/components/tree-map/canvas-utils.js
@@ -11,17 +11,17 @@
  * canvas. The main canvas dimensions match the parent div, but the CSS can be
  * transformed to be zoomed and dragged around (potentially creating a blurry
  * canvas once zoomed in). The zoom canvas is a zoomed in section that matches
  * the parent div's dimensions and is kept in place through CSS. A zoomed in
  * view of the visualization is drawn onto this canvas, providing a crisp zoomed
  * in view of the tree map.
  */
 const { debounce } = require("devtools/shared/debounce");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const FULLSCREEN_STYLE = {
   width: "100%",
   height: "100%",
   position: "absolute",
 };
 

--- a/devtools/client/memory/components/tree-map/drag-zoom.js
+++ b/devtools/client/memory/components/tree-map/drag-zoom.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 { debounce } = require("devtools/shared/debounce");
 const { lerp } = require("devtools/client/memory/utils");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 const LERP_SPEED = 0.5;
 const ZOOM_SPEED = 0.01;
 const TRANSLATE_EPSILON = 1;
 const ZOOM_EPSILON = 0.001;
 const LINE_SCROLL_MODE = 1;
 const SCROLL_LINE_SIZE = 15;
 

--- 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 { Task } = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { MemoryFront } = require("devtools/shared/fronts/memory");
 const HeapAnalysesClient = require("devtools/shared/heapsnapshot/HeapAnalysesClient");
 
 function MemoryPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;
 
   EventEmitter.decorate(this);

--- a/devtools/client/netmonitor/index.html
+++ b/devtools/client/netmonitor/index.html
@@ -15,17 +15,17 @@
       "use strict";
 
       const { BrowserLoader } = Components.utils.import("resource://devtools/client/shared/browser-loader.js", {});
       const require = window.windowRequire = BrowserLoader({
         baseURI: "resource://devtools/client/netmonitor/",
         window,
       }).require;
 
-      const EventEmitter = require("devtools/shared/event-emitter");
+      const EventEmitter = require("devtools/shared/old-event-emitter");
       const { createFactory } = require("devtools/client/shared/vendor/react");
       const { render, unmountComponentAtNode } = require("devtools/client/shared/vendor/react-dom");
       const Provider = createFactory(require("devtools/client/shared/vendor/react-redux").Provider);
       const { bindActionCreators } = require("devtools/client/shared/vendor/redux");
       const { configureStore } = require("./src/utils/create-store");
       const store = configureStore();
       const actions = bindActionCreators(require("./src/actions/index"), store.dispatch);
       const { onFirefoxConnect, onDisconnect } = require("./src/connector/index");

--- a/devtools/client/netmonitor/webpack.config.js
+++ b/devtools/client/netmonitor/webpack.config.js
@@ -69,17 +69,17 @@ let webpackConfig = {
       "devtools/client/shared/vendor/jszip": "jszip",
       "devtools/client/shared/widgets/tooltip/HTMLTooltip": path.join(__dirname, "../../client/shared/widgets/tooltip/HTMLTooltip"),
       "devtools/client/shared/widgets/tooltip/ImageTooltipHelper": path.join(__dirname, "../../client/shared/widgets/tooltip/ImageTooltipHelper"),
       "devtools/client/shared/widgets/tooltip/TooltipToggle": path.join(__dirname, "../../client/shared/widgets/tooltip/TooltipToggle"),
       "devtools/client/shared/widgets/Chart": path.join(__dirname, "../../client/shared/widgets/Chart"),
       "devtools/client/sourceeditor/editor": "devtools-source-editor/src/source-editor",
       "devtools/shared/async-utils": path.join(__dirname, "../../shared/async-utils"),
       "devtools/shared/defer": path.join(__dirname, "../../shared/defer"),
-      "devtools/shared/event-emitter": "devtools-modules/src/utils/event-emitter",
+      "devtools/shared/old-event-emitter": "devtools-modules/src/utils/event-emitter",
       "devtools/shared/fronts/timeline": path.join(__dirname, "../../shared/shims/fronts/timeline"),
       "devtools/shared/l10n": path.join(__dirname, "../../shared/l10n"),
       "devtools/shared/locales": path.join(__dirname, "../../shared/locales/en-US"),
       "devtools/shared/platform/clipboard": path.join(__dirname, "../../shared/platform/content/clipboard"),
       "devtools/shared/plural-form": path.join(__dirname, "../../shared/plural-form"),
       "devtools/shared/task": path.join(__dirname, "../../shared/task"),
       "toolkit/locales": path.join(__dirname, "../../../toolkit/locales/en-US"),
       "Services": "devtools-modules/src/Services",

--- a/devtools/client/performance/modules/widgets/graphs.js
+++ b/devtools/client/performance/modules/widgets/graphs.js
@@ -9,17 +9,17 @@
 
 const { Task } = require("devtools/shared/task");
 const { Heritage } = require("devtools/client/shared/widgets/view-helpers");
 const LineGraphWidget = require("devtools/client/shared/widgets/LineGraphWidget");
 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");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 const { colorUtils } = require("devtools/shared/css/color");
 const { getColor } = require("devtools/client/shared/theme");
 const ProfilerGlobal = require("devtools/client/performance/modules/global");
 const { MarkersOverview } = require("devtools/client/performance/modules/widgets/markers-overview");
 const { createTierGraphDataFromFrameNode } = require("devtools/client/performance/modules/logic/jit");
 
 /**

--- a/devtools/client/performance/modules/widgets/marker-details.js
+++ b/devtools/client/performance/modules/widgets/marker-details.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";
 
 /**
  * This file contains the rendering code for the marker sidebar.
  */
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { MarkerDOMUtils } = require("devtools/client/performance/modules/marker-dom-utils");
 
 /**
  * A detailed view for one single marker.
  *
  * @param nsIDOMNode parent
  *        The parent node holding the view.
  * @param nsIDOMNode splitter

--- a/devtools/client/performance/panel.js
+++ b/devtools/client/performance/panel.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 { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "EventEmitter",
-  "devtools/shared/event-emitter");
+  "devtools/shared/old-event-emitter");
 
 function PerformancePanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this.toolbox = toolbox;
 
   EventEmitter.decorate(this);
 }
 

--- a/devtools/client/performance/performance-controller.js
+++ b/devtools/client/performance/performance-controller.js
@@ -35,17 +35,17 @@ var Waterfall = React.createFactory(requ
 var JITOptimizationsView = React.createFactory(require("devtools/client/performance/components/jit-optimizations"));
 var RecordingControls = React.createFactory(require("devtools/client/performance/components/recording-controls"));
 var RecordingButton = React.createFactory(require("devtools/client/performance/components/recording-button"));
 var RecordingList = React.createFactory(require("devtools/client/performance/components/recording-list"));
 var RecordingListItem = React.createFactory(require("devtools/client/performance/components/recording-list-item"));
 
 var Services = require("Services");
 var promise = require("promise");
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var flags = require("devtools/shared/flags");
 var system = require("devtools/shared/system");
 
 // Logic modules
 /* exported L10N, PerformanceTelemetry, TIMELINE_BLUEPRINT, RecordingUtils,
    PerformanceUtils, OptimizationsGraph, GraphsController,
    MarkerDetails, MarkerBlueprintUtils, WaterfallUtils, FrameUtils, CallView, ThreadNode,

--- a/devtools/client/responsive.html/manager.js
+++ b/devtools/client/responsive.html/manager.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 } = require("chrome");
 const promise = require("promise");
 const { Task } = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { startup } = require("./utils/window");
 const message = require("./utils/message");
 const { swapToInnerBrowser } = require("./browser/swap");
 const { EmulationFront } = require("devtools/shared/fronts/emulation");
 const { getStr } = require("./utils/l10n");
 
 const TOOL_URL = "chrome://devtools/content/responsive.html/index.xhtml";
 

--- a/devtools/client/responsivedesign/responsivedesign.jsm
+++ b/devtools/client/responsivedesign/responsivedesign.jsm
@@ -5,17 +5,17 @@
 "use strict";
 
 const Cu = Components.utils;
 
 const { loader, require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const { Task } = require("devtools/shared/task");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 loader.lazyImporter(this, "SystemAppProxy",
                     "resource://gre/modules/SystemAppProxy.jsm");
 loader.lazyImporter(this, "BrowserUtils",
                     "resource://gre/modules/BrowserUtils.jsm");
 loader.lazyRequireGetter(this, "Telemetry", "devtools/client/shared/telemetry");
 loader.lazyRequireGetter(this, "showDoorhanger",
                          "devtools/client/shared/doorhanger", true);

--- a/devtools/client/scratchpad/scratchpad-panel.js
+++ b/devtools/client/scratchpad/scratchpad-panel.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 {Cu} = require("chrome");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const promise = require("promise");
 
 
 function ScratchpadPanel(iframeWindow, toolbox) {
   let { Scratchpad } = iframeWindow;
   this._toolbox = toolbox;
   this.panelWin = iframeWindow;
   this.scratchpad = Scratchpad;

--- a/devtools/client/scratchpad/scratchpad.js
+++ b/devtools/client/scratchpad/scratchpad.js
@@ -42,17 +42,17 @@ const TAB_SIZE = "devtools.editor.tabsiz
 const FALLBACK_CHARSET_LIST = "intl.fallbackCharsetList.ISO-8859-1";
 
 const VARIABLES_VIEW_URL = "chrome://devtools/content/shared/widgets/VariablesView.xul";
 
 const {require, loader} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 
 const Editor = require("devtools/client/sourceeditor/editor");
 const TargetFactory = require("devtools/client/framework/target").TargetFactory;
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {DevToolsWorker} = require("devtools/shared/worker/worker");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const flags = require("devtools/shared/flags");
 const promise = require("promise");
 const Services = require("Services");
 const {gDevTools} = require("devtools/client/framework/devtools");
 const {Heritage} = require("devtools/client/shared/widgets/view-helpers");
 

--- a/devtools/client/shadereditor/panel.js
+++ b/devtools/client/shadereditor/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 { Cc, Ci, Cu, Cr } = require("chrome");
 const promise = require("promise");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { WebGLFront } = require("devtools/shared/fronts/webgl");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 
 function ShaderEditorPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;
   this._destroyer = null;
 

--- a/devtools/client/shadereditor/shadereditor.js
+++ b/devtools/client/shadereditor/shadereditor.js
@@ -5,17 +5,17 @@
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
 const {SideMenuWidget} = require("resource://devtools/client/shared/widgets/SideMenuWidget.jsm");
 const promise = require("promise");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const Tooltip = require("devtools/client/shared/widgets/tooltip/Tooltip");
 const Editor = require("devtools/client/sourceeditor/editor");
 const {LocalizationHelper} = require("devtools/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:

--- a/devtools/client/shared/autocomplete-popup.js
+++ b/devtools/client/shared/autocomplete-popup.js
@@ -3,17 +3,17 @@
  * 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 HTML_NS = "http://www.w3.org/1999/xhtml";
 const Services = require("Services");
 const {HTMLTooltip} = require("devtools/client/shared/widgets/tooltip/HTMLTooltip");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {PrefObserver} = require("devtools/client/shared/prefs");
 
 let itemIdCounter = 0;
 /**
  * Autocomplete popup UI implementation.
  *
  * @constructor
  * @param {Document} toolboxDoc

--- a/devtools/client/shared/developer-toolbar.js
+++ b/devtools/client/shared/developer-toolbar.js
@@ -24,17 +24,17 @@ loader.lazyGetter(this, "prefBranch", fu
 });
 
 loader.lazyRequireGetter(this, "gcliInit", "devtools/shared/gcli/commands/index");
 loader.lazyRequireGetter(this, "util", "gcli/util/util");
 loader.lazyRequireGetter(this, "ConsoleServiceListener", "devtools/server/actors/utils/webconsole-listeners", true);
 loader.lazyRequireGetter(this, "gDevTools", "devtools/client/framework/devtools", true);
 loader.lazyRequireGetter(this, "gDevToolsBrowser", "devtools/client/framework/devtools-browser", true);
 loader.lazyRequireGetter(this, "nodeConstants", "devtools/shared/dom-node-constants");
-loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
+loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/old-event-emitter");
 
 /**
  * A collection of utilities to help working with commands
  */
 var CommandUtils = {
   /**
    * Caches requisitions created when calling executeOnTarget:
    * Target => Requisition Promise

--- a/devtools/client/shared/devtools-file-watcher.js
+++ b/devtools/client/shared/devtools-file-watcher.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 { Ci } = require("chrome");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 loader.lazyImporter(this, "OS", "resource://gre/modules/osfile.jsm");
 
 const HOTRELOAD_PREF = "devtools.loader.hotreload";
 
 function resolveResourcePath(uri) {
   const handler = Services.io.getProtocolHandler("resource")
         .QueryInterface(Ci.nsIResProtocolHandler);

--- a/devtools/client/shared/inplace-editor.js
+++ b/devtools/client/shared/inplace-editor.js
@@ -37,17 +37,17 @@ const CONTENT_TYPES = {
 
 // The limit of 500 autocomplete suggestions should not be reached but is kept
 // for safety.
 const MAX_POPUP_ENTRIES = 500;
 
 const FOCUS_FORWARD = focusManager.MOVEFOCUS_FORWARD;
 const FOCUS_BACKWARD = focusManager.MOVEFOCUS_BACKWARD;
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { findMostRelevantCssPropertyIndex } = require("./suggestion-picker");
 
 /**
  * Helper to check if the provided key matches one of the expected keys.
  * Keys will be prefixed with DOM_VK_ and should match a key in KeyCodes.
  *
  * @param {String} key
  *        the key to check (can be a keyCode).

--- a/devtools/client/shared/key-shortcuts.js
+++ b/devtools/client/shared/key-shortcuts.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const isOSX = Services.appinfo.OS === "Darwin";
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 
 // List of electron keys mapped to DOM API (DOM_VK_*) key code
 const ElectronKeysMapping = {
   "F1": "DOM_VK_F1",
   "F2": "DOM_VK_F2",
   "F3": "DOM_VK_F3",

--- a/devtools/client/shared/options-view.js
+++ b/devtools/client/shared/options-view.js
@@ -1,11 +1,11 @@
 "use strict";
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const Services = require("Services");
 const { Preferences } = require("resource://gre/modules/Preferences.jsm");
 const OPTIONS_SHOWN_EVENT = "options-shown";
 const OPTIONS_HIDDEN_EVENT = "options-hidden";
 const PREF_CHANGE_EVENT = "pref-changed";
 
 /**
  * OptionsView constructor. Takes several options, all required:

--- a/devtools/client/shared/output-parser.js
+++ b/devtools/client/shared/output-parser.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 {angleUtils} = require("devtools/client/shared/css-angle");
 const {colorUtils} = require("devtools/shared/css/color");
 const {getCSSLexer} = require("devtools/shared/css/lexer");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {
   ANGLE_TAKING_FUNCTIONS,
   BASIC_SHAPE_FUNCTIONS,
   BEZIER_KEYWORDS,
   COLOR_TAKING_FUNCTIONS,
   CSS_TYPES
 } = require("devtools/shared/css/properties-db");
 const {appendText} = require("devtools/client/inspector/shared/utils");

--- a/devtools/client/shared/prefs.js
+++ b/devtools/client/shared/prefs.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 Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 /**
  * Shortcuts for lazily accessing and setting various preferences.
  * Usage:
  *   let prefs = new Prefs("root.path.to.branch", {
  *     myIntPref: ["Int", "leaf.path.to.my-int-pref"],
  *     myCharPref: ["Char", "leaf.path.to.my-char-pref"],
  *     myJsonPref: ["Json", "leaf.path.to.my-json-pref"],

--- a/devtools/client/shared/widgets/AbstractTreeItem.jsm
+++ b/devtools/client/shared/widgets/AbstractTreeItem.jsm
@@ -7,17 +7,17 @@
 
 const { interfaces: Ci, utils: Cu } = Components;
 
 const { require, loader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 const { ViewHelpers } = require("devtools/client/shared/widgets/view-helpers");
 const { KeyCodes } = require("devtools/client/shared/keycodes");
 
-loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
+loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/old-event-emitter");
 
 XPCOMUtils.defineLazyModuleGetter(this, "console",
   "resource://gre/modules/Console.jsm");
 
 this.EXPORTED_SYMBOLS = ["AbstractTreeItem"];
 
 /**
  * A very generic and low-level tree view implementation. It is not intended

--- a/devtools/client/shared/widgets/BreadcrumbsWidget.jsm
+++ b/devtools/client/shared/widgets/BreadcrumbsWidget.jsm
@@ -6,17 +6,17 @@
 "use strict";
 
 const Cu = Components.utils;
 
 const ENSURE_SELECTION_VISIBLE_DELAY = 50; // ms
 
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { ViewHelpers, setNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 this.EXPORTED_SYMBOLS = ["BreadcrumbsWidget"];
 
 /**
  * A breadcrumb-like list of items.
  *
  * Note: this widget should be used in tandem with the WidgetMethods in
  * view-helpers.js.

--- a/devtools/client/shared/widgets/Chart.js
+++ b/devtools/client/shared/widgets/Chart.js
@@ -7,17 +7,17 @@ const NET_STRINGS_URI = "devtools/client
 const SVG_NS = "http://www.w3.org/2000/svg";
 const PI = Math.PI;
 const TAU = PI * 2;
 const EPSILON = 0.0000001;
 const NAMED_SLICE_MIN_ANGLE = TAU / 8;
 const NAMED_SLICE_TEXT_DISTANCE_RATIO = 1.9;
 const HOVERED_SLICE_TRANSLATE_DISTANCE_RATIO = 20;
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const L10N = new LocalizationHelper(NET_STRINGS_URI);
 
 /**
  * A factory for creating charts.
  * Example usage: let myChart = Chart.Pie(document, { ... });
  */
 var Chart = {

--- a/devtools/client/shared/widgets/ColorWidget.js
+++ b/devtools/client/shared/widgets/ColorWidget.js
@@ -5,17 +5,17 @@
 /**
  * This file is a new working copy of Spectrum.js for the purposes of refreshing the color
  * widget. It is hidden behind a pref("devtools.inspector.colorWidget.enabled").
  */
 
 "use strict";
 
 const {Task} = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {colorUtils} = require("devtools/shared/css/color");
 const {LocalizationHelper} = require("devtools/shared/l10n");
 const L10N = new LocalizationHelper("devtools/client/locales/inspector.properties");
 
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 const SAMPLE_TEXT = "Abc";
 
 /**

--- a/devtools/client/shared/widgets/CubicBezierWidget.js
+++ b/devtools/client/shared/widgets/CubicBezierWidget.js
@@ -20,17 +20,17 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
 // Based on www.cubic-bezier.com by Lea Verou
 // See https://github.com/LeaVerou/cubic-bezier
 
 "use strict";
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {
   PREDEFINED,
   PRESETS,
   DEFAULT_PRESET_CATEGORY
 } = require("devtools/client/shared/widgets/CubicBezierPresets");
 const {getCSSLexer} = require("devtools/shared/css/lexer");
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 

--- a/devtools/client/shared/widgets/FastListWidget.js
+++ b/devtools/client/shared/widgets/FastListWidget.js
@@ -1,16 +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/. */
 "use strict";
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { ViewHelpers } = require("devtools/client/shared/widgets/view-helpers");
 
 /**
  * A list menu widget that attempts to be very fast.
  *
  * Note: this widget should be used in tandem with the WidgetMethods in
  * view-helpers.js.
  *

--- a/devtools/client/shared/widgets/FilterWidget.js
+++ b/devtools/client/shared/widgets/FilterWidget.js
@@ -4,17 +4,17 @@
 
 "use strict";
 
 /**
   * This is a CSS Filter Editor widget used
   * for Rule View's filter swatches
   */
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { Cc, Ci } = require("chrome");
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const STRINGS_URI = "devtools/client/locales/filterwidget.properties";
 const L10N = new LocalizationHelper(STRINGS_URI);
 
 const {cssTokenizer} = require("devtools/shared/css/parsing-utils");

--- a/devtools/client/shared/widgets/FlameGraph.js
+++ b/devtools/client/shared/widgets/FlameGraph.js
@@ -4,17 +4,17 @@
 "use strict";
 
 const { Task } = require("devtools/shared/task");
 const { ViewHelpers, setNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 const { ELLIPSIS } = require("devtools/shared/l10n");
 
 loader.lazyRequireGetter(this, "defer", "devtools/shared/defer");
 loader.lazyRequireGetter(this, "EventEmitter",
-  "devtools/shared/event-emitter");
+  "devtools/shared/old-event-emitter");
 
 loader.lazyRequireGetter(this, "getColor",
   "devtools/client/shared/theme", true);
 
 loader.lazyRequireGetter(this, "CATEGORY_MAPPINGS",
   "devtools/client/performance/modules/categories", true);
 loader.lazyRequireGetter(this, "FrameUtils",
   "devtools/client/performance/modules/logic/frame-utils");

--- a/devtools/client/shared/widgets/Graphs.js
+++ b/devtools/client/shared/widgets/Graphs.js
@@ -4,17 +4,17 @@
 "use strict";
 
 const { Task } = require("devtools/shared/task");
 const { setNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 const { getCurrentZoom } = require("devtools/shared/layout/utils");
 
 loader.lazyRequireGetter(this, "defer", "devtools/shared/defer");
 loader.lazyRequireGetter(this, "EventEmitter",
-  "devtools/shared/event-emitter");
+  "devtools/shared/old-event-emitter");
 
 loader.lazyImporter(this, "DevToolsWorker",
   "resource://devtools/shared/worker/worker.js");
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const GRAPH_SRC = "chrome://devtools/content/shared/widgets/graphs-frame.xhtml";
 const WORKER_URL =
   "resource://devtools/client/shared/widgets/GraphsWorker.js";

--- a/devtools/client/shared/widgets/MdnDocsWidget.js
+++ b/devtools/client/shared/widgets/MdnDocsWidget.js
@@ -22,17 +22,17 @@
  * the content in a tooltip, use this in conjunction with Tooltip.js.
  */
 
 "use strict";
 
 const Services = require("Services");
 const defer = require("devtools/shared/defer");
 const {getCSSLexer} = require("devtools/shared/css/lexer");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {gDevTools} = require("devtools/client/framework/devtools");
 
 const {LocalizationHelper} = require("devtools/shared/l10n");
 const L10N = new LocalizationHelper("devtools/client/locales/inspector.properties");
 
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 
 // Parameters for the XHR request

--- a/devtools/client/shared/widgets/SideMenuWidget.jsm
+++ b/devtools/client/shared/widgets/SideMenuWidget.jsm
@@ -6,17 +6,17 @@
 "use strict";
 
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 const SHARED_STRINGS_URI = "devtools/client/locales/shared.properties";
 
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const { ViewHelpers } = require("devtools/client/shared/widgets/view-helpers");
 
 this.EXPORTED_SYMBOLS = ["SideMenuWidget"];
 
 /**
  * Localization convenience methods.
  */

--- a/devtools/client/shared/widgets/Spectrum.js
+++ b/devtools/client/shared/widgets/Spectrum.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 
 /**
  * Spectrum creates a color picker widget in any container you give it.
  *
  * Simple usage example:
  *
  * const {Spectrum} = require("devtools/client/shared/widgets/Spectrum");

--- a/devtools/client/shared/widgets/TableWidget.js
+++ b/devtools/client/shared/widgets/TableWidget.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 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, "naturalSortCaseInsensitive",
   "devtools/client/shared/natural-sort", true);
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 

--- a/devtools/client/shared/widgets/TreeWidget.js
+++ b/devtools/client/shared/widgets/TreeWidget.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 HTML_NS = "http://www.w3.org/1999/xhtml";
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 
 /**
  * A tree widget with keyboard navigation and collapsable structure.
  *
  * @param {nsIDOMNode} node
  *        The container element for the tree widget.
  * @param {Object} options

--- a/devtools/client/shared/widgets/VariablesView.jsm
+++ b/devtools/client/shared/widgets/VariablesView.jsm
@@ -13,17 +13,17 @@ const LAZY_EMPTY_DELAY = 150; // 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
 
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const Services = require("Services");
 const { getSourceNames } = require("devtools/client/shared/source-utils");
 const promise = require("promise");
 const defer = require("devtools/shared/defer");
 const { Heritage, ViewHelpers, setNamedTimeout } =
   require("devtools/client/shared/widgets/view-helpers");
 const { Task } = require("devtools/shared/task");

--- a/devtools/client/shared/widgets/tooltip/HTMLTooltip.js
+++ b/devtools/client/shared/widgets/tooltip/HTMLTooltip.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {TooltipToggle} = require("devtools/client/shared/widgets/tooltip/TooltipToggle");
 const {listenOnce} = require("devtools/shared/async-utils");
 const {Task} = require("devtools/shared/task");
 
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 
 const POSITION = {

--- a/devtools/client/shared/widgets/tooltip/InlineTooltip.js
+++ b/devtools/client/shared/widgets/tooltip/InlineTooltip.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 /**
  * The InlineTooltip can display widgets for the CSS Rules view in an
  * inline container.
  *
  * @param {Document} doc
  *        The toolbox document to attach the InlineTooltip container.
  */

--- a/devtools/client/shared/widgets/tooltip/SwatchBasedEditorTooltip.js
+++ b/devtools/client/shared/widgets/tooltip/SwatchBasedEditorTooltip.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 const {HTMLTooltip} = require("devtools/client/shared/widgets/tooltip/HTMLTooltip");
 const InlineTooltip = require("devtools/client/shared/widgets/tooltip/InlineTooltip");
 
 const INLINE_TOOLTIP_CLASS = "inline-tooltip-container";
 
 /**
  * Base class for all (color, gradient, ...)-swatch based value editors inside

--- a/devtools/client/shared/widgets/tooltip/Tooltip.js
+++ b/devtools/client/shared/widgets/tooltip/Tooltip.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 defer = require("devtools/shared/defer");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 const {TooltipToggle} = require("devtools/client/shared/widgets/tooltip/TooltipToggle");
 
 const XHTML_NS = "http://www.w3.org/1999/xhtml";
 const ESCAPE_KEYCODE = KeyCodes.DOM_VK_ESCAPE;
 const POPUP_EVENTS = ["shown", "hidden", "showing", "hiding"];
 
 /**

--- a/devtools/client/sourceeditor/editor.js
+++ b/devtools/client/sourceeditor/editor.js
@@ -25,17 +25,17 @@ const VALID_KEYMAPS = new Set(["emacs", 
 const MAX_VERTICAL_OFFSET = 3;
 
 // Match @Scratchpad/N:LINE[:COLUMN] or (LINE[:COLUMN]) anywhere at an end of
 // line in text selection.
 const RE_SCRATCHPAD_ERROR = /(?:@Scratchpad\/\d+:|\()(\d+):?(\d+)?(?:\)|\n)/;
 const RE_JUMP_TO_LINE = /^(\d+):?(\d+)?/;
 
 const Services = require("Services");
-const events = require("devtools/shared/event-emitter");
+const events = require("devtools/shared/old-event-emitter");
 const { PrefObserver } = require("devtools/client/shared/prefs");
 const { getClientCssProperties } = require("devtools/shared/fronts/css-properties");
 const KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 
 const {LocalizationHelper} = require("devtools/shared/l10n");
 const L10N = new LocalizationHelper("devtools/client/locales/sourceeditor.properties");
 
 const {

--- a/devtools/client/storage/panel.js
+++ b/devtools/client/storage/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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 loader.lazyRequireGetter(this, "StorageFront",
                          "devtools/shared/fronts/storage", true);
 loader.lazyRequireGetter(this, "StorageUI",
                          "devtools/client/storage/ui", true);
 
 var StoragePanel = this.StoragePanel =
 function StoragePanel(panelWin, toolbox) {

--- a/devtools/client/storage/ui.js
+++ b/devtools/client/storage/ui.js
@@ -1,17 +1,17 @@
 /* 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("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {LocalizationHelper, ELLIPSIS} = require("devtools/shared/l10n");
 const KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 const JSOL = require("devtools/client/shared/vendor/jsol");
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 
 // GUID to be used as a separator in compound keys. This must match the same
 // constant in devtools/server/actors/storage.js,
 // devtools/client/storage/test/head.js and

--- a/devtools/client/styleeditor/StyleEditorUI.jsm
+++ b/devtools/client/styleeditor/StyleEditorUI.jsm
@@ -10,17 +10,17 @@ this.EXPORTED_SYMBOLS = ["StyleEditorUI"
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const Services = require("Services");
 const {NetUtil} = require("resource://gre/modules/NetUtil.jsm");
 const {OS} = require("resource://gre/modules/osfile.jsm");
 const {Task} = require("devtools/shared/task");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {gDevTools} = require("devtools/client/framework/devtools");
 const {
   getString,
   text,
   wire,
   showFilePicker,
 } = require("resource://devtools/client/styleeditor/StyleEditorUtil.jsm");
 const {SplitView} = require("resource://devtools/client/shared/SplitView.jsm");

--- a/devtools/client/styleeditor/StyleSheetEditor.jsm
+++ b/devtools/client/styleeditor/StyleSheetEditor.jsm
@@ -12,17 +12,17 @@ const Ci = Components.interfaces;
 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 {shortSource, prettifyCSS} = 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 EventEmitter = require("devtools/shared/old-event-emitter");
 const {Task} = require("devtools/shared/task");
 const {FileUtils} = require("resource://gre/modules/FileUtils.jsm");
 const {NetUtil} = require("resource://gre/modules/NetUtil.jsm");
 const {OS} = Cu.import("resource://gre/modules/osfile.jsm", {});
 const {
   getString,
   showFilePicker,
 } = require("resource://devtools/client/styleeditor/StyleEditorUtil.jsm");

--- a/devtools/client/styleeditor/styleeditor-panel.js
+++ b/devtools/client/styleeditor/styleeditor-panel.js
@@ -3,17 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 var Services = require("Services");
 var promise = require("promise");
 var {Task} = require("devtools/shared/task");
 var {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 
 var {StyleEditorUI} = require("resource://devtools/client/styleeditor/StyleEditorUI.jsm");
 var {getString} = require("resource://devtools/client/styleeditor/StyleEditorUtil.jsm");
 var {initCssProperties} = require("devtools/shared/fronts/css-properties");
 
 loader.lazyGetter(this, "StyleSheetsFront",
   () => require("devtools/shared/fronts/stylesheets").StyleSheetsFront);
 

--- a/devtools/client/webaudioeditor/includes.js
+++ b/devtools/client/webaudioeditor/includes.js
@@ -5,17 +5,17 @@
 
 var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 const { loader, require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 const { EventTarget } = require("sdk/event/target");
 const { Task } = require("devtools/shared/task");
 const { Class } = require("sdk/core/heritage");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const Services = require("Services");
 const { gDevTools } = require("devtools/client/framework/devtools");
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const { ViewHelpers } = require("devtools/client/shared/widgets/view-helpers");
 
 const STRINGS_URI = "devtools/client/locales/webaudioeditor.properties";
 const L10N = new LocalizationHelper(STRINGS_URI);

--- a/devtools/client/webaudioeditor/panel.js
+++ b/devtools/client/webaudioeditor/panel.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 { Cc, Ci, Cu, Cr } = require("chrome");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { WebAudioFront } = require("devtools/shared/fronts/webaudio");
 var Promise = require("promise");
 
 function WebAudioEditorPanel(iframeWindow, toolbox) {
   this.panelWin = iframeWindow;
   this._toolbox = toolbox;
   this._destroyer = null;
 

--- a/devtools/client/webconsole/jsterm.js
+++ b/devtools/client/webconsole/jsterm.js
@@ -11,17 +11,17 @@ const {Utils: WebConsoleUtils} =
 const promise = require("promise");
 const Debugger = require("Debugger");
 const Services = require("Services");
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 
 loader.lazyServiceGetter(this, "clipboardHelper",
                          "@mozilla.org/widget/clipboardhelper;1",
                          "nsIClipboardHelper");
-loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
+loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/old-event-emitter");
 loader.lazyRequireGetter(this, "AutocompletePopup", "devtools/client/shared/autocomplete-popup");
 loader.lazyRequireGetter(this, "ToolSidebar", "devtools/client/framework/sidebar", true);
 loader.lazyRequireGetter(this, "Messages", "devtools/client/webconsole/console-output", true);
 loader.lazyRequireGetter(this, "asyncStorage", "devtools/shared/async-storage");
 loader.lazyRequireGetter(this, "EnvironmentClient", "devtools/shared/client/main", true);
 loader.lazyRequireGetter(this, "ObjectClient", "devtools/shared/client/main", true);
 loader.lazyImporter(this, "VariablesView", "resource://devtools/client/shared/widgets/VariablesView.jsm");
 loader.lazyImporter(this, "VariablesViewController", "resource://devtools/client/shared/widgets/VariablesViewController.jsm");

--- a/devtools/client/webconsole/new-console-output/new-console-output-wrapper.js
+++ b/devtools/client/webconsole/new-console-output/new-console-output-wrapper.js
@@ -8,17 +8,17 @@ const React = require("devtools/client/s
 const ReactDOM = require("devtools/client/shared/vendor/react-dom");
 const { Provider } = require("devtools/client/shared/vendor/react-redux");
 
 const actions = require("devtools/client/webconsole/new-console-output/actions/index");
 const { batchActions } = require("devtools/client/shared/redux/middleware/debounce");
 const { createContextMenu } = require("devtools/client/webconsole/new-console-output/utils/context-menu");
 const { configureStore } = require("devtools/client/webconsole/new-console-output/store");
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const ConsoleOutput = React.createFactory(require("devtools/client/webconsole/new-console-output/components/console-output"));
 const FilterBar = React.createFactory(require("devtools/client/webconsole/new-console-output/components/filter-bar"));
 
 let store = null;
 let queuedActions = [];
 let throttledDispatchTimeout = false;
 
 function NewConsoleOutputWrapper(parentNode, jsterm, toolbox, owner, document) {

--- a/devtools/client/webconsole/new-console-output/test/chrome/test_render_perf.html
+++ b/devtools/client/webconsole/new-console-output/test/chrome/test_render_perf.html
@@ -23,17 +23,17 @@ const NUM_MESSAGES = 4000;
 const NUM_STREAMING = 100;
 Components.utils.import("resource://gre/modules/FileUtils.jsm");
 const Services = browserRequire("Services");
 Services.prefs.setIntPref("devtools.hud.loglimit", NUM_MESSAGES);
 const NewConsoleOutputWrapper = browserRequire(
   "devtools/client/webconsole/new-console-output/new-console-output-wrapper");
 const actions =
   browserRequire("devtools/client/webconsole/new-console-output/actions/index");
-const EventEmitter = browserRequire("devtools/shared/event-emitter");
+const EventEmitter = browserRequire("devtools/shared/old-event-emitter");
 const testPackets = Array.from({length: NUM_MESSAGES}).map((el, id) => ({
   "from": "server1.conn4.child1/consoleActor2",
   "type": "consoleAPICall",
   "message": {
     "arguments": [
       "foobar",
       `${id % 2 === 0 ? "Even" : "Odd"} text`,
       id

--- a/devtools/client/webconsole/new-webconsole.js
+++ b/devtools/client/webconsole/new-webconsole.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 {Utils: WebConsoleUtils} = require("devtools/client/webconsole/utils");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const promise = require("promise");
 const defer = require("devtools/shared/defer");
 const Services = require("Services");
 const { gDevTools } = require("devtools/client/framework/devtools");
 const { JSTerm } = require("devtools/client/webconsole/jsterm");
 const { WebConsoleConnectionProxy } = require("devtools/client/webconsole/webconsole-connection-proxy");
 const KeyShortcuts = require("devtools/client/shared/key-shortcuts");
 const { l10n } = require("devtools/client/webconsole/new-console-output/utils/messages");

--- a/devtools/client/webconsole/panel.js
+++ b/devtools/client/webconsole/panel.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 promise = require("promise");
 
 loader.lazyGetter(this, "HUDService", () => require("devtools/client/webconsole/hudservice"));
-loader.lazyGetter(this, "EventEmitter", () => require("devtools/shared/event-emitter"));
+loader.lazyGetter(this, "EventEmitter", () => require("devtools/shared/old-event-emitter"));
 
 /**
  * A DevToolPanel that controls the Web Console.
  */
 function WebConsolePanel(iframeWindow, toolbox) {
   this._frameWindow = iframeWindow;
   this._toolbox = toolbox;
   EventEmitter.decorate(this);

--- a/devtools/client/webconsole/webconsole.js
+++ b/devtools/client/webconsole/webconsole.js
@@ -17,17 +17,17 @@ Cu.import("resource://devtools/client/sh
 const promise = require("promise");
 const Services = require("Services");
 const Telemetry = require("devtools/client/shared/telemetry");
 const {PrefObserver} = require("devtools/client/shared/prefs");
 
 loader.lazyServiceGetter(this, "clipboardHelper",
                          "@mozilla.org/widget/clipboardhelper;1",
                          "nsIClipboardHelper");
-loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
+loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/old-event-emitter");
 loader.lazyRequireGetter(this, "ConsoleOutput", "devtools/client/webconsole/console-output", true);
 loader.lazyRequireGetter(this, "Messages", "devtools/client/webconsole/console-output", true);
 loader.lazyRequireGetter(this, "EnvironmentClient", "devtools/shared/client/main", true);
 loader.lazyRequireGetter(this, "ObjectClient", "devtools/shared/client/main", true);
 loader.lazyRequireGetter(this, "system", "devtools/shared/system");
 loader.lazyRequireGetter(this, "JSTerm", "devtools/client/webconsole/jsterm", true);
 loader.lazyRequireGetter(this, "gSequenceId", "devtools/client/webconsole/jsterm", true);
 loader.lazyImporter(this, "VariablesView", "resource://devtools/client/shared/widgets/VariablesView.jsm");

--- a/devtools/client/webconsole/webpack.config.js
+++ b/devtools/client/webconsole/webpack.config.js
@@ -71,17 +71,17 @@ webpackConfig.resolve = {
     "devtools/client/shared/components/reps/reps": path.join(__dirname, "../../client/shared/components/reps/reps"),
     "devtools/client/shared/redux/middleware/thunk": path.join(__dirname, "../../client/shared/redux/middleware/thunk"),
     "devtools/client/shared/redux/middleware/debounce": path.join(__dirname, "../../client/shared/redux/middleware/debounce"),
     "devtools/client/shared/components/stack-trace": path.join(__dirname, "../../client/shared/components/stack-trace"),
     "devtools/client/shared/source-utils": path.join(__dirname, "../../client/shared/source-utils"),
     "devtools/client/shared/components/frame": path.join(__dirname, "../../client/shared/components/frame"),
 
     "devtools/shared/defer": path.join(__dirname, "../../shared/defer"),
-    "devtools/shared/event-emitter": "devtools-modules/shared/event-emitter",
+    "devtools/shared/old-event-emitter": "devtools-modules/shared/event-emitter",
     "devtools/shared/client/main": path.join(__dirname, "new-console-output/test/fixtures/ObjectClient"),
     "devtools/shared/platform/clipboard": path.join(__dirname, "../../shared/platform/content/clipboard"),
   }
 };
 
 const mappings = [
   [
     /utils\/menu/, "devtools-launchpad/src/components/shared/menu"

--- a/devtools/client/webide/content/monitor.js
+++ b/devtools/client/webide/content/monitor.js
@@ -3,17 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 var Cu = Components.utils;
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const Services = require("Services");
 const {AppManager} = require("devtools/client/webide/modules/app-manager");
 const {AppActorFront} = require("devtools/shared/apps/app-actor-front");
 const {Connection} = require("devtools/shared/client/connection-manager");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 window.addEventListener("load", function () {
   window.addEventListener("resize", Monitor.resize);
   window.addEventListener("unload", Monitor.unload);
 
   document.querySelector("#close").onclick = () => {
     window.parent.UI.openProject();
   };

--- a/devtools/client/webide/content/simulator.js
+++ b/devtools/client/webide/content/simulator.js
@@ -4,17 +4,17 @@
 
 var Cu = Components.utils;
 var Ci = Components.interfaces;
 
 const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
 const { getDevices, getDeviceString } = require("devtools/client/shared/devices");
 const { Simulators, Simulator } = require("devtools/client/webide/modules/simulators");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const promise = require("promise");
 const utils = require("devtools/client/webide/modules/utils");
 
 const Strings = Services.strings.createBundle("chrome://devtools/locale/webide.properties");
 
 var SimulatorEditor = {
 
   // Available Firefox OS Simulator addons (key: `addon.id`).

--- a/devtools/client/webide/content/webide.js
+++ b/devtools/client/webide/content/webide.js
@@ -8,17 +8,17 @@ var Ci = Components.interfaces;
 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");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const promise = require("promise");
 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");

--- a/devtools/client/webide/modules/addons.js
+++ b/devtools/client/webide/modules/addons.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 {AddonManager} = require("resource://gre/modules/AddonManager.jsm");
 const Services = require("Services");
 const {getJSON} = require("devtools/client/shared/getjson");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 const ADDONS_URL = "devtools.webide.addonsURL";
 
 var SIMULATOR_LINK = Services.prefs.getCharPref("devtools.webide.simulatorAddonsURL");
 var ADB_LINK = Services.prefs.getCharPref("devtools.webide.adbAddonURL");
 var ADAPTERS_LINK = Services.prefs.getCharPref("devtools.webide.adaptersAddonURL");
 var SIMULATOR_ADDON_ID = Services.prefs.getCharPref("devtools.webide.simulatorAddonID");
 var ADB_ADDON_ID = Services.prefs.getCharPref("devtools.webide.adbAddonID");

--- a/devtools/client/webide/modules/app-manager.js
+++ b/devtools/client/webide/modules/app-manager.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/. */
 
 const {Cu} = require("chrome");
 
 const {TargetFactory} = require("devtools/client/framework/target");
 const Services = require("Services");
 const {FileUtils} = Cu.import("resource://gre/modules/FileUtils.jsm", {});
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {OS} = Cu.import("resource://gre/modules/osfile.jsm", {});
 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/shared/fronts/device");
 const {getPreferenceFront} = require("devtools/shared/fronts/preference");

--- a/devtools/client/webide/modules/app-projects.js
+++ b/devtools/client/webide/modules/app-projects.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 {Cc, Ci, Cu, Cr} = require("chrome");
 
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {generateUUID} = Cc["@mozilla.org/uuid-generator;1"].getService(Ci.nsIUUIDGenerator);
 const {FileUtils} = Cu.import("resource://gre/modules/FileUtils.jsm", {});
 
 /**
  * IndexedDB wrapper that just save project objects
  *
  * The only constraint is that project objects have to have
  * a unique `location` object.

--- a/devtools/client/webide/modules/config-view.js
+++ b/devtools/client/webide/modules/config-view.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const Services = require("Services");
 const Strings = Services.strings.createBundle("chrome://devtools/locale/webide.properties");
 
 var ConfigView;
 
 module.exports = ConfigView = function (window) {
   EventEmitter.decorate(this);
   this._doc = window.document;

--- a/devtools/client/webide/modules/project-list.js
+++ b/devtools/client/webide/modules/project-list.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/. */
 
 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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 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;
 

--- a/devtools/client/webide/modules/runtime-list.js
+++ b/devtools/client/webide/modules/runtime-list.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 Services = require("Services");
 const {AppManager} = require("devtools/client/webide/modules/app-manager");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {RuntimeScanners, WiFiScanner} = require("devtools/client/webide/modules/runtimes");
 const {Devices} = require("resource://devtools/shared/apps/Devices.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;

--- a/devtools/client/webide/modules/runtimes.js
+++ b/devtools/client/webide/modules/runtimes.js
@@ -6,17 +6,17 @@
 
 const {Ci} = require("chrome");
 const Services = require("Services");
 const {Devices} = require("resource://devtools/shared/apps/Devices.jsm");
 const {Connection} = require("devtools/shared/client/connection-manager");
 const {DebuggerServer} = require("devtools/server/main");
 const {Simulators} = require("devtools/client/webide/modules/simulators");
 const discovery = require("devtools/shared/discovery/discovery");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const promise = require("promise");
 loader.lazyRequireGetter(this, "AuthenticationResult",
   "devtools/shared/security/auth", true);
 loader.lazyRequireGetter(this, "DevToolsUtils",
   "devtools/shared/DevToolsUtils");
 
 const Strings = Services.strings.createBundle("chrome://devtools/locale/webide.properties");
 

--- a/devtools/client/webide/modules/simulator-process.js
+++ b/devtools/client/webide/modules/simulator-process.js
@@ -4,17 +4,17 @@
  */
 
 "use strict";
 
 const { Cc, Ci, Cu } = require("chrome");
 
 const Environment = Cc["@mozilla.org/process/environment;1"]
                       .getService(Ci.nsIEnvironment);
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const Services = require("Services");
 
 const {Subprocess} = Cu.import("resource://gre/modules/Subprocess.jsm", {});
 
 loader.lazyGetter(this, "OS", () => {
   switch (Services.appinfo.OS) {
     case "Darwin":
       return "mac64";

--- a/devtools/client/webide/modules/simulators.js
+++ b/devtools/client/webide/modules/simulators.js
@@ -6,17 +6,17 @@
 
 const { AddonManager } = require("resource://gre/modules/AddonManager.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 EventEmitter = require("devtools/shared/old-event-emitter");
 const Services = require("Services");
 
 const SimulatorRegExp = new RegExp(Services.prefs.getCharPref("devtools.webide.simulatorAddonRegExp"));
 const LocaleCompare = (a, b) => {
   return a.name.toLowerCase().localeCompare(b.name.toLowerCase());
 };
 
 var Simulators = {

--- a/devtools/client/webide/modules/tab-store.js
+++ b/devtools/client/webide/modules/tab-store.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 } = require("chrome");
 
 const { TargetFactory } = require("devtools/client/framework/target");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { Connection } = require("devtools/shared/client/connection-manager");
 const { Task } = require("devtools/shared/task");
 
 const _knownTabStores = new WeakMap();
 
 var TabStore;
 
 module.exports = TabStore = function (connection) {

--- a/devtools/client/webide/test/test_simulators.html
+++ b/devtools/client/webide/test/test_simulators.html
@@ -14,17 +14,17 @@
 
   <body>
 
     <script type="application/javascript">
       window.onload = function() {
         SimpleTest.waitForExplicitFinish();
 
         const asyncStorage = require("devtools/shared/async-storage");
-        const EventEmitter = require("devtools/shared/event-emitter");
+        const EventEmitter = require("devtools/shared/old-event-emitter");
         const { GetAvailableAddons } = require("devtools/client/webide/modules/addons");
         const { getDevices } = require("devtools/client/shared/devices");
         const { Simulator, Simulators } = require("devtools/client/webide/modules/simulators");
         const { AddonSimulatorProcess,
                 OldAddonSimulatorProcess,
                 CustomSimulatorProcess } = require("devtools/client/webide/modules/simulator-process");
 
         function addonStatus(addon, status) {

--- a/devtools/docs/getting-started/development-profiles.md
+++ b/devtools/docs/getting-started/development-profiles.md
@@ -25,17 +25,17 @@ Next time you start Firefox with `./mach
 ## Enable additional logging
 
 You can change the value of these preferences by going to `about:config`:
 
 | Preference name | Value | Comments |
 | --------------- | --------------- | -------- |
 | `browser.dom.window.dump.enabled` | `true` | Adds global `dump` function to log strings to `stdout` |
 | `devtools.debugger.log` (*) | `true` | Dump packets sent over remote debugging protocol to `stdout`.<br /><br />The [remote protocol inspector add-on](https://github.com/firebug/rdp-inspector/wiki) might be useful too. |
-| `devtools.dump.emit` (*) | `true` | Log event notifications from the EventEmitter class<br />(found at `devtools/shared/event-emitter.js`). |
+| `devtools.dump.emit` (*) | `true` | Log event notifications from the EventEmitter class<br />(found at `devtools/shared/old-event-emitter.js`). |
 
 Preferences marked with a (`*`) also require `browser.dom.window.dump.enabled` in order to work. You might not want to enable *all* of those all the time, as they can cause the output to be way too verbose, but they might be useful if you're working on a server actor, for example<!--TODO link to actors doc-->.
 
 Restart the browser to apply configuration changes.
 
 ## Enable remote debugging and the Browser Toolbox
 
 These settings allow you to use the [browser toolbox](https://developer.mozilla.org/docs/Tools/Browser_Toolbox) to inspect the DevTools themselves, set breakpoints inside of DevTools code, and run the [Scratchpad](https://developer.mozilla.org/en-US/docs/Tools/Scratchpad) in the *Browser* environment.

--- a/devtools/server/actors/highlighters.js
+++ b/devtools/server/actors/highlighters.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, Cu } = require("chrome");
 
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const events = require("sdk/event/core");
 const protocol = require("devtools/shared/protocol");
 const Services = require("Services");
 const { isWindowIncluded } = require("devtools/shared/layout/utils");
 const { highlighterSpec, customHighlighterSpec } = require("devtools/shared/specs/highlighters");
 const { isXUL } = require("./highlighters/utils/markup");
 const { SimpleOutlineHighlighter } = require("./highlighters/simple-outline");
 

--- a/devtools/server/actors/highlighters/auto-refresh.js
+++ b/devtools/server/actors/highlighters/auto-refresh.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 { Cu } = require("chrome");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { isNodeValid } = require("./utils/markup");
 const { getAdjustedQuads, getCurrentZoom,
         getWindowDimensions } = require("devtools/shared/layout/utils");
 
 // Note that the order of items in this array is important because it is used
 // for drawing the BoxModelHighlighter's path elements correctly.
 const BOX_MODEL_REGIONS = ["margin", "border", "padding", "content"];
 const QUADS_PROPS = ["p1", "p2", "p3", "p4", "bounds"];

--- a/devtools/server/actors/highlighters/eye-dropper.js
+++ b/devtools/server/actors/highlighters/eye-dropper.js
@@ -6,17 +6,17 @@
 // Eye-dropper tool. This is implemented as a highlighter so it can be displayed in the
 // content page.
 // It basically displays a magnifier that tracks mouse moves and shows a magnified version
 // of the page. On click, it samples the color at the pixel being hovered.
 
 const {Ci, Cc} = require("chrome");
 const {CanvasFrameAnonymousContentHelper, createNode} = require("./utils/markup");
 const Services = require("Services");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {rgbToHsl, rgbToColorName} = require("devtools/shared/css/color").colorUtils;
 const {getCurrentZoom, getFrameOffsets} = require("devtools/shared/layout/utils");
 
 loader.lazyGetter(this, "clipboardHelper",
   () => Cc["@mozilla.org/widget/clipboardhelper;1"].getService(Ci.nsIClipboardHelper));
 loader.lazyGetter(this, "l10n",
   () => Services.strings.createBundle("chrome://devtools-shared/locale/eyedropper.properties"));
 

--- a/devtools/server/actors/highlighters/shapes.js
+++ b/devtools/server/actors/highlighters/shapes.js
@@ -10,17 +10,17 @@ const { setIgnoreLayoutChanges, getCurre
 const { AutoRefreshHighlighter } = require("./auto-refresh");
 const {
   getDistance,
   clickedOnEllipseEdge,
   distanceToLine,
   projection,
   clickedOnPoint
 } = require("devtools/server/actors/utils/shapes-geometry-utils");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 const BASE_MARKER_SIZE = 10;
 // the width of the area around highlighter lines that can be clicked, in px
 const LINE_CLICK_WIDTH = 5;
 const DOM_EVENTS = ["mousedown", "mousemove", "mouseup", "dblclick"];
 const _dragging = Symbol("shapes/dragging");
 
 /**

--- a/devtools/server/actors/reflow.js
+++ b/devtools/server/actors/reflow.js
@@ -23,17 +23,17 @@
  *   listens to reflow events via the docshell,
  *   These dedicated classes are used by the LayoutChangesObserver.
  */
 
 const {Ci} = require("chrome");
 const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
 const protocol = require("devtools/shared/protocol");
 const events = require("sdk/event/core");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {reflowSpec} = require("devtools/shared/specs/reflow");
 
 /**
  * The reflow actor tracks reflows and emits events about them.
  */
 exports.ReflowActor = protocol.ActorClassWithSpec(reflowSpec, {
   initialize: function (conn, tabActor) {
     protocol.Actor.prototype.initialize.call(this, conn);

--- a/devtools/server/actors/utils/TabSources.js
+++ b/devtools/server/actors/utils/TabSources.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 DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const { assert, fetch } = DevToolsUtils;
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { OriginalLocation, GeneratedLocation } = require("devtools/server/actors/common");
 const { resolve } = require("promise");
 const { joinURI } = require("devtools/shared/path");
 
 loader.lazyRequireGetter(this, "SourceActor", "devtools/server/actors/source", true);
 loader.lazyRequireGetter(this, "isEvalSource", "devtools/server/actors/source", true);
 loader.lazyRequireGetter(this, "SourceMapConsumer", "source-map", true);
 loader.lazyRequireGetter(this, "SourceMapGenerator", "source-map", true);

--- a/devtools/server/actors/utils/make-debugger.js
+++ b/devtools/server/actors/utils/make-debugger.js
@@ -1,17 +1,17 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2; 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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const Debugger = require("Debugger");
 
 const { reportException } = require("devtools/shared/DevToolsUtils");
 
 /**
  * Multiple actors that use a |Debugger| instance come in a few versions, each
  * with a different set of debuggees. One version for content tabs (globals
  * within a tab), one version for chrome debugging (all globals), and sometimes

--- a/devtools/server/main.js
+++ b/devtools/server/main.js
@@ -12,17 +12,17 @@ var { Ci, Cc, CC, Cu, Cr } = require("ch
 var Services = require("Services");
 var { ActorPool, OriginalLocation, RegisteredActorFactory,
       ObservedActorFactory } = require("devtools/server/actors/common");
 var { LocalDebuggerTransport, ChildDebuggerTransport, WorkerDebuggerTransport } =
   require("devtools/shared/transport/transport");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var { dumpn, dumpv } = DevToolsUtils;
 var flags = require("devtools/shared/flags");
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 var Promise = require("promise");
 var SyncPromise = require("devtools/shared/deprecated-sync-thenables");
 
 DevToolsUtils.defineLazyGetter(this, "DebuggerSocket", () => {
   let { DebuggerSocket } = require("devtools/shared/security/socket");
   return DebuggerSocket;
 });
 DevToolsUtils.defineLazyGetter(this, "Authentication", () => {

--- a/devtools/server/tests/unit/test_monitor_actor.js
+++ b/devtools/server/tests/unit/test_monitor_actor.js
@@ -3,17 +3,17 @@
 
 /**
  * Test the monitor actor.
  */
 
 "use strict";
 
 function run_test() {
-  let EventEmitter = require("devtools/shared/event-emitter");
+  let EventEmitter = require("devtools/shared/old-event-emitter");
 
   function MonitorClient(client, form) {
     this.client = client;
     this.actor = form.monitorActor;
     this.events = ["update"];
 
     EventEmitter.decorate(this);
     client.registerClient(this);

--- a/devtools/server/tests/unit/test_registerClient.js
+++ b/devtools/server/tests/unit/test_registerClient.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 // Test the DebuggerClient.registerClient API
 
-var EventEmitter = require("devtools/shared/event-emitter");
+var EventEmitter = require("devtools/shared/old-event-emitter");
 
 var gClient;
 var gTestClient;
 
 function TestActor(conn) {
   this.conn = conn;
 }
 TestActor.prototype = {

--- a/devtools/shared/apps/Devices.jsm
+++ b/devtools/shared/apps/Devices.jsm
@@ -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 { require } = Components.utils.import("resource://devtools/shared/Loader.jsm", {});
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 /* exported EXPORTED_SYMBOLS */
 
 const EXPORTED_SYMBOLS = ["Devices"];
 
 var addonInstalled = false;
 
 const Devices = {

--- a/devtools/shared/apps/Simulator.jsm
+++ b/devtools/shared/apps/Simulator.jsm
@@ -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 { require } = Components.utils.import("resource://devtools/shared/Loader.jsm", {});
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 /**
  * TODO (Bug 1132453) The `Simulator` module is deprecated, and should be
  * removed once all simulator addons stop using it (see bug 1132452).
  *
  * If you want to register, unregister, or otherwise deal with installed
  * simulators, please use the `Simulators` module defined in:
  *

--- a/devtools/shared/apps/app-actor-front.js
+++ b/devtools/shared/apps/app-actor-front.js
@@ -6,17 +6,17 @@
 
 const {Ci, Cc, Cr} = require("chrome");
 const {OS} = require("resource://gre/modules/osfile.jsm");
 const {FileUtils} = require("resource://gre/modules/FileUtils.jsm");
 const {NetUtil} = require("resource://gre/modules/NetUtil.jsm");
 const promise = require("promise");
 const defer = require("devtools/shared/defer");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 // Bug 1188401: When loaded from xpcshell tests, we do not have browser/ files
 // and can't load target.js. Should be fixed by bug 912121.
 loader.lazyRequireGetter(this, "TargetFactory", "devtools/client/framework/target", true);
 
 // XXX: bug 912476 make this module a real protocol.js front
 // by converting webapps actor to protocol.js
 

--- a/devtools/shared/client/connection-manager.js
+++ b/devtools/shared/client/connection-manager.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, Cr} = require("chrome");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const { DebuggerServer } = require("devtools/server/main");
 const { DebuggerClient } = require("devtools/shared/client/main");
 const Services = require("Services");
 const { Task } = require("devtools/shared/task");
 
 const REMOTE_TIMEOUT = "devtools.debugger.remote-timeout";
 
 /**

--- a/devtools/shared/discovery/discovery.js
+++ b/devtools/shared/discovery/discovery.js
@@ -27,17 +27,17 @@
  * scan.
  *
  * When a service is registered, is supplies a regular object with any details
  * about itself (a port number, for example) in a service-defined format, which
  * is then available to scanning devices.
  */
 
 const { Cu, CC, Cc, Ci } = require("chrome");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const Services = require("Services");
 
 const UDPSocket = CC("@mozilla.org/network/udp-socket;1",
                      "nsIUDPSocket",
                      "init");
 
 const SCAN_PORT = 50624;
 const UPDATE_PORT = 50625;

--- a/devtools/shared/discovery/tests/unit/test_discovery.js
+++ b/devtools/shared/discovery/tests/unit/test_discovery.js
@@ -5,17 +5,17 @@
 "use strict";
 
 var Cu = Components.utils;
 
 const { require } =
   Cu.import("resource://devtools/shared/Loader.jsm", {});
 const Services = require("Services");
 const defer = require("devtools/shared/defer");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const discovery = require("devtools/shared/discovery/discovery");
 const { setTimeout, clearTimeout } = Cu.import("resource://gre/modules/Timer.jsm", {});
 
 Services.prefs.setBoolPref("devtools.discovery.log", true);
 
 do_register_cleanup(() => {
   Services.prefs.clearUserPref("devtools.discovery.log");
 });

--- a/devtools/shared/gcli/command-state.js
+++ b/devtools/shared/gcli/command-state.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 const getTargetId = ({tab}) => tab.linkedBrowser.outerWindowID;
 const enabledCommands = new Map();
 
 /**
  * The `CommandState` is a singleton that provides utility methods to keep the commands'
  * state in sync between the toolbox, the toolbar and the content.
  */

--- a/devtools/shared/moz.build
+++ b/devtools/shared/moz.build
@@ -47,25 +47,25 @@ DevToolsModules(
     'builtin-modules.js',
     'content-observer.js',
     'debounce.js',
     'defer.js',
     'deprecated-sync-thenables.js',
     'DevToolsUtils.js',
     'dom-node-constants.js',
     'dom-node-filter-constants.js',
-    'event-emitter.js',
     'extend.js',
     'flags.js',
     'generate-uuid.js',
     'indentation.js',
     'indexed-db.js',
     'l10n.js',
     'loader-plugin-raw.jsm',
     'Loader.jsm',
+    'old-event-emitter.js',
     'Parser.jsm',
     'path.js',
     'plural-form.js',
     'protocol.js',
     'system.js',
     'task.js',
     'ThreadSafeDevToolsUtils.js',
     'wasm-source-map.js',

rename from devtools/shared/event-emitter.js
rename to devtools/shared/old-event-emitter.js

--- a/devtools/shared/shims/event-emitter.js
+++ b/devtools/shared/shims/event-emitter.js
@@ -29,17 +29,17 @@
   const Services = require("Services");
   const WARNING_PREF = "devtools.migration.warnings";
   // Cu and Services aren't accessible from workers
   if (Cu && Services && Services.prefs &&
       Services.prefs.getBoolPref(WARNING_PREF)) {
     const { Deprecated } =
       Cu.import("resource://gre/modules/Deprecated.jsm", {});
     Deprecated.warning("This path to event-emitter.js is deprecated.  Please " +
-                       "use require(\"devtools/shared/event-emitter\") to " +
+                       "use require(\"devtools/shared/old-event-emitter\") to " +
                        "load this module.",
                        "https://bugzil.la/912121");
   }
 
-  const EventEmitter = require("devtools/shared/event-emitter");
+  const EventEmitter = require("devtools/shared/old-event-emitter");
   this.EventEmitter = EventEmitter;
   module.exports = EventEmitter;
 });

--- a/devtools/shared/tests/mochitest/test_eventemitter_basic.html
+++ b/devtools/shared/tests/mochitest/test_eventemitter_basic.html
@@ -19,17 +19,17 @@
   <body>
 
     <script type="application/javascript">
       "use strict";
 
       const { utils: Cu } = Components;
       const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
       const promise = require("promise");
-      const EventEmitter = require("devtools/shared/event-emitter");
+      const EventEmitter = require("devtools/shared/old-event-emitter");
       const { Task } = require("devtools/shared/task");
 
       SimpleTest.waitForExplicitFinish();
 
       testEmitter();
       testEmitter({});
 
       Task.spawn(testPromise)

--- a/devtools/shared/transport/stream-utils.js
+++ b/devtools/shared/transport/stream-utils.js
@@ -3,17 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const { Ci, Cc, Cr, CC } = require("chrome");
 const Services = require("Services");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const { dumpv } = DevToolsUtils;
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const defer = require("devtools/shared/defer");
 
 DevToolsUtils.defineLazyGetter(this, "IOUtil", () => {
   return Cc["@mozilla.org/io-util;1"].getService(Ci.nsIIOUtil);
 });
 
 DevToolsUtils.defineLazyGetter(this, "ScriptableInputStream", () => {
   return CC("@mozilla.org/scriptableinputstream;1",

--- a/devtools/shared/transport/transport.js
+++ b/devtools/shared/transport/transport.js
@@ -26,17 +26,17 @@
   const DevToolsUtils = require("devtools/shared/DevToolsUtils");
   const { dumpn, dumpv } = DevToolsUtils;
   const flags = require("devtools/shared/flags");
   const StreamUtils = require("devtools/shared/transport/stream-utils");
   const { Packet, JSONPacket, BulkPacket } =
   require("devtools/shared/transport/packets");
   const promise = require("promise");
   const defer = require("devtools/shared/defer");
-  const EventEmitter = require("devtools/shared/event-emitter");
+  const EventEmitter = require("devtools/shared/old-event-emitter");
 
   DevToolsUtils.defineLazyGetter(this, "Pipe", () => {
     return CC("@mozilla.org/pipe;1", "nsIPipe", "init");
   });
 
   DevToolsUtils.defineLazyGetter(this, "ScriptableInputStream", () => {
     return CC("@mozilla.org/scriptableinputstream;1",
             "nsIScriptableInputStream", "init");

--- a/devtools/shared/transport/websocket-transport.js
+++ b/devtools/shared/transport/websocket-transport.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 EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 
 function WebSocketDebuggerTransport(socket) {
   EventEmitter.decorate(this);
 
   this.active = false;
   this.hooks = null;
   this.socket = socket;
 }

--- a/devtools/shared/webconsole/client.js
+++ b/devtools/shared/webconsole/client.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 DevToolsUtils = require("devtools/shared/DevToolsUtils");
-const EventEmitter = require("devtools/shared/event-emitter");
+const EventEmitter = require("devtools/shared/old-event-emitter");
 const {LongStringClient} = require("devtools/shared/client/main");
 
 /**
  * A WebConsoleClient is used as a front end for the WebConsoleActor that is
  * created on the server, hiding implementation details.
  *
  * @param object debuggerClient
  *        The DebuggerClient instance we live for.