--- a/devtools/client/aboutdebugging/test/browser_addons_debug_bootstrapped.js
+++ b/devtools/client/aboutdebugging/test/browser_addons_debug_bootstrapped.js
@@ -3,17 +3,17 @@
 "use strict";
 
 // Avoid test timeouts that can occur while waiting for the "addon-console-works" message.
 requestLongerTimeout(2);
 
 const ADDON_ID = "test-devtools@mozilla.org";
 const ADDON_NAME = "test-devtools";
 
-const { BrowserToolboxProcess } = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
+const { BrowserToolboxProcess } = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
 
 add_task(function* () {
   yield new Promise(resolve => {
     let options = {"set": [
       // Force enabling of addons debugging
       ["devtools.chrome.enabled", true],
       ["devtools.debugger.remote-enabled", true],
       // Disable security prompt

--- a/devtools/client/aboutdebugging/test/browser_addons_debug_webextension.js
+++ b/devtools/client/aboutdebugging/test/browser_addons_debug_webextension.js
@@ -7,17 +7,17 @@
 requestLongerTimeout(2);
 
 const ADDON_ID = "test-devtools-webextension@mozilla.org";
 const ADDON_NAME = "test-devtools-webextension";
 const ADDON_MANIFEST_PATH = "addons/test-devtools-webextension/manifest.json";
 
 const {
   BrowserToolboxProcess
-} = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
+} = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
 
 /**
  * This test file ensures that the webextension addon developer toolbox:
  * - when the debug button is clicked on a webextension, the opened toolbox
  *   has a working webconsole with the background page as default target;
  */
 add_task(function* testWebExtensionsToolboxWebConsole() {
   let {

--- a/devtools/client/aboutdebugging/test/browser_addons_debug_webextension_inspector.js
+++ b/devtools/client/aboutdebugging/test/browser_addons_debug_webextension_inspector.js
@@ -6,17 +6,17 @@
 requestLongerTimeout(2);
 
 const ADDON_ID = "test-devtools-webextension@mozilla.org";
 const ADDON_NAME = "test-devtools-webextension";
 const ADDON_PATH = "addons/test-devtools-webextension/manifest.json";
 
 const {
   BrowserToolboxProcess
-} = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
+} = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
 
 /**
  * This test file ensures that the webextension addon developer toolbox:
  * - the webextension developer toolbox has a working Inspector panel, with the
  *   background page as default target;
  */
 add_task(function* testWebExtensionsToolboxInspector() {
   let {

--- a/devtools/client/aboutdebugging/test/browser_addons_debug_webextension_nobg.js
+++ b/devtools/client/aboutdebugging/test/browser_addons_debug_webextension_nobg.js
@@ -6,17 +6,17 @@
 requestLongerTimeout(2);
 
 const ADDON_NOBG_ID = "test-devtools-webextension-nobg@mozilla.org";
 const ADDON_NOBG_NAME = "test-devtools-webextension-nobg";
 const ADDON_NOBG_PATH = "addons/test-devtools-webextension-nobg/manifest.json";
 
 const {
   BrowserToolboxProcess
-} = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
+} = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
 
 /**
  * This test file ensures that the webextension addon developer toolbox:
  * - the webextension developer toolbox is connected to a fallback page when the
  *   background page is not available (and in the fallback page document body contains
  *   the expected message, which warns the user that the current page is not a real
  *   webextension context);
  */

--- a/devtools/client/aboutdebugging/test/browser_addons_debug_webextension_popup.js
+++ b/devtools/client/aboutdebugging/test/browser_addons_debug_webextension_popup.js
@@ -6,17 +6,17 @@
 requestLongerTimeout(2);
 
 const ADDON_ID = "test-devtools-webextension@mozilla.org";
 const ADDON_NAME = "test-devtools-webextension";
 const ADDON_MANIFEST_PATH = "addons/test-devtools-webextension/manifest.json";
 
 const {
   BrowserToolboxProcess
-} = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
+} = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
 
 /**
  * This test file ensures that the webextension addon developer toolbox:
  * - when the debug button is clicked on a webextension, the opened toolbox
  *   has a working webconsole with the background page as default target;
  * - the webextension developer toolbox has a working Inspector panel, with the
  *   background page as default target;
  * - the webextension developer toolbox is connected to a fallback page when the

--- a/devtools/client/aboutdebugging/test/head.js
+++ b/devtools/client/aboutdebugging/test/head.js
@@ -7,18 +7,18 @@
 
 "use strict";
 
 // Load the shared-head file first.
 Services.scriptloader.loadSubScript(
   "chrome://mochitests/content/browser/devtools/client/framework/test/shared-head.js",
   this);
 
-const { AddonManager } = Cu.import("resource://gre/modules/AddonManager.jsm", {});
-const { Management } = Cu.import("resource://gre/modules/Extension.jsm", {});
+const { AddonManager } = ChromeUtils.import("resource://gre/modules/AddonManager.jsm", {});
+const { Management } = ChromeUtils.import("resource://gre/modules/Extension.jsm", {});
 
 flags.testing = true;
 registerCleanupFunction(() => {
   flags.testing = false;
 });
 
 function* openAboutDebugging(page, win) {
   info("opening about:debugging");

--- a/devtools/client/aboutdebugging/test/xpcshell-head.js
+++ b/devtools/client/aboutdebugging/test/xpcshell-head.js
@@ -1,8 +1,8 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
 
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});

--- a/devtools/client/animationinspector/animation-controller.js
+++ b/devtools/client/animationinspector/animation-controller.js
@@ -7,17 +7,17 @@
 /* animation-panel.js is loaded in the same scope but we don't use
    import-globals-from to avoid infinite loops since animation-panel.js already
    imports globals from animation-controller.js */
 /* globals AnimationsPanel */
 /* eslint no-unused-vars: [2, {"vars": "local", "args": "none"}] */
 
 "use strict";
 
-var { loader, require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { loader, require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var { Task } = require("devtools/shared/task");
 
 loader.lazyRequireGetter(this, "promise");
 loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
 loader.lazyRequireGetter(this, "AnimationsFront", "devtools/shared/fronts/animation", true);
 
 const { LocalizationHelper } = require("devtools/shared/l10n");
 const L10N =

--- a/devtools/client/animationinspector/test/unit/test_findOptimalTimeInterval.js
+++ b/devtools/client/animationinspector/test/unit/test_findOptimalTimeInterval.js
@@ -1,17 +1,17 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 /* eslint no-eval:0 */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {findOptimalTimeInterval} = require("devtools/client/animationinspector/utils");
 
 // This test array contains objects that are used to test the
 // findOptimalTimeInterval function. Each object should have the following
 // properties:
 // - desc: an optional string that will be printed out
 // - minTimeInterval: a number that represents the minimum time in ms
 //   that should be displayed in one interval

--- a/devtools/client/animationinspector/test/unit/test_formatStopwatchTime.js
+++ b/devtools/client/animationinspector/test/unit/test_formatStopwatchTime.js
@@ -1,16 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {formatStopwatchTime} = require("devtools/client/animationinspector/utils");
 
 const TEST_DATA = [{
   desc: "Formatting 0",
   time: 0,
   expected: "00:00.000"
 }, {
   desc: "Formatting null",

--- a/devtools/client/animationinspector/test/unit/test_getCssPropertyName.js
+++ b/devtools/client/animationinspector/test/unit/test_getCssPropertyName.js
@@ -1,16 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {getCssPropertyName} = require("devtools/client/animationinspector/utils");
 
 const TEST_DATA = [{
   jsName: "alllowercase",
   cssName: "alllowercase"
 }, {
   jsName: "borderWidth",
   cssName: "border-width"

--- a/devtools/client/animationinspector/test/unit/test_timeScale.js
+++ b/devtools/client/animationinspector/test/unit/test_timeScale.js
@@ -1,16 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {TimeScale} = require("devtools/client/animationinspector/utils");
 const TEST_ANIMATIONS = [{
   desc: "Testing a few standard animations",
   animations: [{
     previousStartTime: 500,
     delay: 0,
     duration: 1000,
     iterationCount: 1,

--- a/devtools/client/animationinspector/test/unit/test_timeScale_dimensions.js
+++ b/devtools/client/animationinspector/test/unit/test_timeScale_dimensions.js
@@ -1,16 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    https://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {TimeScale} = require("devtools/client/animationinspector/utils");
 
 const TEST_ENDDELAY_X = [{
   desc: "Testing positive-endDelay animations",
   animations: [{
     previousStartTime: 0,
     duration: 500,
     playbackRate: 1,

--- a/devtools/client/canvasdebugger/canvasdebugger.js
+++ b/devtools/client/canvasdebugger/canvasdebugger.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 { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.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/old-event-emitter");
 const { CallWatcherFront } = require("devtools/shared/fronts/call-watcher");
 const { CanvasFront } = require("devtools/shared/fronts/canvas");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");

--- a/devtools/client/canvasdebugger/test/head.js
+++ b/devtools/client/canvasdebugger/test/head.js
@@ -1,14 +1,14 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 var { generateUUID } = Cc["@mozilla.org/uuid-generator;1"].getService(Ci.nsIUUIDGenerator);
-var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 var Services = require("Services");
 var promise = require("promise");
 const defer = require("devtools/shared/defer");
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { DebuggerClient } = require("devtools/shared/client/debugger-client");
 var { DebuggerServer } = require("devtools/server/main");
 var { CallWatcherFront } = require("devtools/shared/fronts/call-watcher");

--- a/devtools/client/commandline/test/browser_cmd_highlight_02.js
+++ b/devtools/client/commandline/test/browser_cmd_highlight_02.js
@@ -30,16 +30,16 @@ function test() {
 
     yield helpers.closeToolbar(options);
     yield helpers.closeTab(options);
   }).then(finish, helpers.handleError);
 }
 
 function getHighlighterNumber() {
   return ContentTask.spawn(gBrowser.selectedBrowser, {}, function* () {
-    const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+    const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
     return require("devtools/shared/gcli/commands/highlight").highlighters.length;
   });
 }
 
 function* runCommand(cmd, options) {
   yield helpers.audit(options, [{ setup: cmd, exec: {} }]);
 }

--- a/devtools/client/commandline/test/browser_cmd_screenshot.js
+++ b/devtools/client/commandline/test/browser_cmd_screenshot.js
@@ -5,17 +5,17 @@
 
 // Test that screenshot command works properly
 
 "use strict";
 
 const TEST_URI = "http://example.com/browser/devtools/client/commandline/" +
                  "test/browser_cmd_screenshot.html";
 
-var FileUtils = (Cu.import("resource://gre/modules/FileUtils.jsm", {})).FileUtils;
+var FileUtils = (ChromeUtils.import("resource://gre/modules/FileUtils.jsm", {})).FileUtils;
 
 function test() {
   // This test gets bombarded by a cascade of GCs and often takes 50s so lets be
   // safe and give the test 90s to run.
   requestLongerTimeout(3);
 
   return Task.spawn(spawnTest).then(finish, helpers.handleError);
 }

--- a/devtools/client/commandline/test/head.js
+++ b/devtools/client/commandline/test/head.js
@@ -5,17 +5,17 @@
  /* import-globals-from helpers.js */
  /* import-globals-from mockCommands.js */
 
 "use strict";
 
 const TEST_BASE_HTTP = "http://example.com/browser/devtools/client/commandline/test/";
 const TEST_BASE_HTTPS = "https://example.com/browser/devtools/client/commandline/test/";
 
-var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var { console } = require("resource://gre/modules/Console.jsm");
 var flags = require("devtools/shared/flags");
 
 // Import the GCLI test helper
 var testDir = gTestPath.substr(0, gTestPath.lastIndexOf("/"));
 Services.scriptloader.loadSubScript(testDir + "/helpers.js", this);
 Services.scriptloader.loadSubScript(testDir + "/mockCommands.js", this, "UTF-8");
 

--- a/devtools/client/commandline/test/helpers.js
+++ b/devtools/client/commandline/test/helpers.js
@@ -17,17 +17,17 @@
 "use strict";
 
 // A copy of this code exists in firefox mochitests. They should be kept
 // in sync. Hence the exports synonym for non AMD contexts.
 var { helpers, assert } = (function () {
 
   var helpers = {};
 
-  var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+  var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
   var { TargetFactory } = require("devtools/client/framework/target");
   var { gDevToolsBrowser } = require("devtools/client/framework/devtools-browser");
   var Services = require("Services");
 
   var assert = { ok: ok, is: is, log: info };
   var util = require("gcli/util/util");
   var cli = require("gcli/cli");
   var KeyEvent = require("gcli/util/util").KeyEvent;

--- a/devtools/client/debugger/debugger-controller.js
+++ b/devtools/client/debugger/debugger-controller.js
@@ -89,17 +89,17 @@ const EVENTS = {
 // Descriptions for what a stack frame represents after the debugger pauses.
 const FRAME_TYPE = {
   NORMAL: 0,
   CONDITIONAL_BREAKPOINT_EVAL: 1,
   WATCH_EXPRESSIONS_EVAL: 2,
   PUBLIC_CLIENT_EVAL: 3
 };
 
-const { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
+const { BrowserLoader } = ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
 const { require } = BrowserLoader({
   baseURI: "resource://devtools/client/debugger/",
   window,
 });
 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");

--- a/devtools/client/debugger/new/test/mochitest/browser_dbg-chrome-create.js
+++ b/devtools/client/debugger/new/test/mochitest/browser_dbg-chrome-create.js
@@ -2,17 +2,17 @@
 /* vim: set ft=javascript ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Tests that a chrome debugger can be created in a new process.
  */
 
-const { BrowserToolboxProcess } = Cu.import(
+const { BrowserToolboxProcess } = ChromeUtils.import(
   "resource://devtools/client/framework/ToolboxProcess.jsm",
   {}
 );
 let gProcess = undefined;
 
 function initChromeDebugger() {
   info("Initializing a chrome debugger process.");
   return new Promise(resolve => {

--- a/devtools/client/debugger/new/test/mochitest/browser_dbg-chrome-debugging.js
+++ b/devtools/client/debugger/new/test/mochitest/browser_dbg-chrome-debugging.js
@@ -6,17 +6,17 @@
 /**
  * Tests that chrome debugging works.
  */
 
 var gClient, gThreadClient;
 var gNewGlobal = promise.defer();
 var gNewChromeSource = promise.defer();
 
-var { DevToolsLoader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { DevToolsLoader } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var customLoader = new DevToolsLoader();
 customLoader.invisibleToDebugger = true;
 var { DebuggerServer } = customLoader.require("devtools/server/main");
 var { DebuggerClient } = require("devtools/shared/client/debugger-client");
 
 function initDebuggerClient() {
   DebuggerServer.init();
   DebuggerServer.registerAllActors();

--- a/devtools/client/debugger/test/mochitest/addon-source/browser_dbg_addon4/bootstrap.js
+++ b/devtools/client/debugger/test/mochitest/addon-source/browser_dbg_addon4/bootstrap.js
@@ -4,23 +4,23 @@
 "use strict";
 
 function notify() {
   // Log objects so makeDebuggeeValue can get the global to use
   console.log({ msg: "Hello again" });
 }
 
 function startup(aParams, aReason) {
-  const { Services } = Cu.import("resource://gre/modules/Services.jsm", {});
+  const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm", {});
   let res = Services.io.getProtocolHandler("resource")
                        .QueryInterface(Ci.nsIResProtocolHandler);
   res.setSubstitution("browser_dbg_addon4", aParams.resourceURI);
 
   // Load a JS module
-  Cu.import("resource://browser_dbg_addon4/test.jsm"); // eslint-disable-line mozilla/no-single-arg-cu-import
+  ChromeUtils.import("resource://browser_dbg_addon4/test.jsm"); // eslint-disable-line mozilla/no-single-arg-cu-import
   // Log objects so makeDebuggeeValue can get the global to use
   console.log({ msg: "Hello from the test add-on" });
 
   Services.obs.addObserver(notify, "addon-test-ping");
 }
 
 function shutdown(aParams, aReason) {
   Services.obs.removeObserver(notify, "addon-test-ping");

--- a/devtools/client/debugger/test/mochitest/browser_dbg_addon-modules-unpacked.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_addon-modules-unpacked.js
@@ -31,17 +31,17 @@ function test() {
     ok(sources[0].url.endsWith("/browser_dbg_addon5/bootstrap.js"), "correct url for bootstrap code");
     is(sources[0].label, "bootstrap.js", "correct label for bootstrap code");
     is(sources[1].url, "resource://browser_dbg_addon5/test.jsm", "correct url for addon code");
     is(sources[1].label, "test.jsm", "correct label for addon code");
     is(sources[2].url, "chrome://browser_dbg_addon5/content/testxul.js", "correct url for addon tab code");
     is(sources[2].label, "testxul.js", "correct label for addon tab code");
 
     // Load a new module and tab and check they appear in the list of sources
-    Cu.import("resource://browser_dbg_addon5/test2.jsm", {});
+    ChromeUtils.import("resource://browser_dbg_addon5/test2.jsm", {});
     let tab2 = yield addTab("chrome://browser_dbg_addon5/content/test2.xul");
 
     groups = yield addonDebugger.getSourceGroups();
     is(groups[0].name, "browser_dbg_addon5@tests.mozilla.org", "Add-on code should be the first group");
     is(groups[1].name, "chrome://global", "XUL code should be the second group");
     is(groups.length, 2, "Should be only two groups.");
 
     sources = groups[0].sources;

--- a/devtools/client/debugger/test/mochitest/browser_dbg_addon-modules.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_addon-modules.js
@@ -30,17 +30,17 @@ function test() {
     ok(sources[0].url.endsWith("/addon4.xpi!/bootstrap.js"), "correct url for bootstrap code");
     is(sources[0].label, "bootstrap.js", "correct label for bootstrap code");
     is(sources[1].url, "resource://browser_dbg_addon4/test.jsm", "correct url for addon code");
     is(sources[1].label, "test.jsm", "correct label for addon code");
     is(sources[2].url, "chrome://browser_dbg_addon4/content/testxul.js", "correct url for addon tab code");
     is(sources[2].label, "testxul.js", "correct label for addon tab code");
 
     // Load a new module and tab and check they appear in the list of sources
-    Cu.import("resource://browser_dbg_addon4/test2.jsm", {});
+    ChromeUtils.import("resource://browser_dbg_addon4/test2.jsm", {});
     let tab2 = yield addTab("chrome://browser_dbg_addon4/content/test2.xul");
 
     groups = yield addonDebugger.getSourceGroups();
     is(groups[0].name, "browser_dbg_addon4@tests.mozilla.org", "Add-on code should be the first group");
     is(groups[1].name, "chrome://global", "XUL code should be the second group");
     is(groups.length, 2, "Should be only two groups.");
 
     sources = groups[0].sources;

--- a/devtools/client/debugger/test/mochitest/browser_dbg_chrome-debugging.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_chrome-debugging.js
@@ -9,17 +9,17 @@
 
 const TAB_URL = EXAMPLE_URL + "doc_inline-debugger-statement.html";
 
 var gClient, gThreadClient;
 var gAttached = promise.defer();
 var gNewGlobal = promise.defer();
 var gNewChromeSource = promise.defer();
 
-var { DevToolsLoader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { DevToolsLoader } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var customLoader = new DevToolsLoader();
 customLoader.invisibleToDebugger = true;
 var { DebuggerServer } = customLoader.require("devtools/server/main");
 
 function test() {
   DebuggerServer.init();
   DebuggerServer.registerAllActors();
   DebuggerServer.allowChromeProcess = true;

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-01.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-01.js
@@ -3,17 +3,17 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Check that simple JS can be parsed and cached with the reflection API.
  */
 
 function test() {
-  let { Parser } = Cu.import("resource://devtools/shared/Parser.jsm", {});
+  let { Parser } = ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let source = "let x = 42;";
   let parser = new Parser();
   let first = parser.get(source);
   let second = parser.get(source);
 
   isnot(first, second,
     "The two syntax trees should be different.");

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-02.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-02.js
@@ -3,17 +3,17 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Check that syntax errors are reported correctly.
  */
 
 function test() {
-  let { Parser } = Cu.import("resource://devtools/shared/Parser.jsm", {});
+  let { Parser } = ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let source = "let x + 42;";
   let parser = new Parser();
   // Don't pollute the logs with exceptions that we are going to check anyhow.
   parser.logExceptions = false;
   let parsed = parser.get(source);
 
   ok(parsed,

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-03.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-03.js
@@ -3,17 +3,17 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Check that JS inside HTML can be separated and parsed correctly.
  */
 
 function test() {
-  let { Parser } = Cu.import("resource://devtools/shared/Parser.jsm", {});
+  let { Parser } = ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let source = [
     "<!doctype html>",
     "<head>",
     "<script>",
     "let a = 42;",
     "</script>",
     "<script type='text/javascript'>",

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-04.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-04.js
@@ -3,17 +3,17 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Check that faulty JS inside HTML can be separated and identified correctly.
  */
 
 function test() {
-  let { Parser } = Cu.import("resource://devtools/shared/Parser.jsm", {});
+  let { Parser } = ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let source = [
     "<!doctype html>",
     "<head>",
     "<SCRIPT>",
     "let a + 42;",
     "</SCRIPT>",
     "<script type='text/javascript'>",

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-05.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-05.js
@@ -4,17 +4,17 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Check that JS code containing strings that might look like <script> tags
  * inside an HTML source is parsed correctly.
  */
 
 function test() {
-  let { Parser } = Cu.import("resource://devtools/shared/Parser.jsm", {});
+  let { Parser } = ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let source = [
     "let a = [];",
     "a.push('<script>');",
     "a.push('var a = 42;');",
     "a.push('</script>');",
     "a.push('<script type=\"text/javascript\">');",
     "a.push('var b = 42;');",

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-06.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-06.js
@@ -5,17 +5,17 @@
 
 /**
  * Check that some potentially problematic identifier nodes have the
  * right location information attached.
  */
 
 function test() {
   let { Parser, ParserHelpers, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   function verify(source, predicate, [sline, scol], [eline, ecol]) {
     let ast = Parser.reflectionAPI.parse(source);
     let node = SyntaxTreeVisitor.filter(ast, predicate).pop();
     let loc = ParserHelpers.getNodeLocation(node);
 
     is(loc.start.toSource(), { line: sline, column: scol }.toSource(),
       "The start location was correct for the identifier in: '" + source + "'.");

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-07.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-07.js
@@ -4,17 +4,17 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Check that nodes with locaiton information attached can be properly
  * verified for containing lines and columns.
  */
 
 function test() {
-  let { ParserHelpers } = Cu.import("resource://devtools/shared/Parser.jsm", {});
+  let { ParserHelpers } = ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let node1 = { loc: {
     start: { line: 1, column: 10 },
     end: { line: 10, column: 1 }
   }};
   let node2 = { loc: {
     start: { line: 1, column: 10 },
     end: { line: 1, column: 20 }

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-08.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-08.js
@@ -4,17 +4,17 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Test that inferring anonymous function information is done correctly.
  */
 
 function test() {
   let { Parser, ParserHelpers, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   function verify(source, predicate, details) {
     let { name, chain } = details;
     let [[sline, scol], [eline, ecol]] = details.loc;
     let ast = Parser.reflectionAPI.parse(source);
     let node = SyntaxTreeVisitor.filter(ast, predicate).pop();
     let info = ParserHelpers.inferFunctionExpressionInfo(node);
 

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-09.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-09.js
@@ -5,17 +5,17 @@
 
 /**
  * Test that inferring anonymous function information is done correctly
  * from arrow expressions.
  */
 
 function test() {
   let { Parser, ParserHelpers, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   function verify(source, predicate, details) {
     let { name, chain } = details;
     let [[sline, scol], [eline, ecol]] = details.loc;
     let ast = Parser.reflectionAPI.parse(source);
     let node = SyntaxTreeVisitor.filter(ast, predicate).pop();
     let info = ParserHelpers.inferFunctionExpressionInfo(node);
 

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-10.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-10.js
@@ -4,17 +4,17 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Test that creating an evaluation string for certain nodes works properly.
  */
 
 function test() {
   let { Parser, ParserHelpers, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   function verify(source, predicate, string) {
     let ast = Parser.reflectionAPI.parse(source);
     let node = SyntaxTreeVisitor.filter(ast, predicate).pop();
     let info = ParserHelpers.getIdentifierEvalString(node);
     is(info, string, "The identifier evaluation string is correct.");
   }
 

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-11.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-11.js
@@ -3,17 +3,17 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Checks if self-closing <script/> tags are parsed by Parser.jsm
  */
 
 function test() {
-  let { Parser } = Cu.import("resource://devtools/shared/Parser.jsm", {});
+  let { Parser } = ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let source = [
     '<script type="text/javascript" src="chrome://foo.js"/>',
     '<script type="application/javascript" src="chrome://baz.js"/>',
     '<script async defer src="chrome://foobar.js"/>',
     '<script type="application/javascript"/>"hello third"',
     '<script type="application/javascript">"hello fourth"</script>',
   ].join("\n");

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-computed-name.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-computed-name.js
@@ -6,17 +6,17 @@
 /**
  * Test that template strings are correctly processed.
  */
 
 "use strict";
 
 function test() {
   let { Parser, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let ast = Parser.reflectionAPI.parse("({ [i]: 1 })");
   let nodes = SyntaxTreeVisitor.filter(ast, e => e.type == "ComputedName");
   ok(nodes && nodes.length === 1, "Found the ComputedName node");
 
   let name = nodes[0].name;
   ok(name, "The ComputedName node has a name property");
   is(name.type, "Identifier", "The name has a correct type");

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-function-defaults.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-function-defaults.js
@@ -6,17 +6,17 @@
 /**
  * Test that function default arguments are correctly processed.
  */
 
 "use strict";
 
 function test() {
   let { Parser, ParserHelpers, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   function verify(source, predicate, string) {
     let ast = Parser.reflectionAPI.parse(source);
     let node = SyntaxTreeVisitor.filter(ast, predicate).pop();
     let info = ParserHelpers.getIdentifierEvalString(node);
     is(info, string, "The identifier evaluation string is correct.");
   }
 

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-spread-expression.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-spread-expression.js
@@ -6,17 +6,17 @@
 /**
  * Test that spread expressions work both in arrays and function calls.
  */
 
 "use strict";
 
 function test() {
   let { Parser, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   const SCRIPTS = ["[...a]", "foo(...a)"];
 
   for (let script of SCRIPTS) {
     info(`Testing spread expression in '${script}'`);
     let ast = Parser.reflectionAPI.parse(script);
     let nodes = SyntaxTreeVisitor.filter(ast,
       e => e.type == "SpreadExpression");

--- a/devtools/client/debugger/test/mochitest/browser_dbg_parser-template-strings.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_parser-template-strings.js
@@ -6,17 +6,17 @@
 /**
  * Test that template strings are correctly processed.
  */
 
 "use strict";
 
 function test() {
   let { Parser, SyntaxTreeVisitor } =
-    Cu.import("resource://devtools/shared/Parser.jsm", {});
+    ChromeUtils.import("resource://devtools/shared/Parser.jsm", {});
 
   let ast = Parser.reflectionAPI.parse("`foo${i}bar`");
   let nodes = SyntaxTreeVisitor.filter(ast, e => e.type == "TemplateLiteral");
   ok(nodes && nodes.length === 1, "Found the TemplateLiteral node");
 
   let elements = nodes[0].elements;
   ok(elements, "The TemplateLiteral node has elements");
   is(elements.length, 3, "There are 3 elements in the literal");

--- a/devtools/client/debugger/test/mochitest/browser_dbg_promises-rejection-stack.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_promises-rejection-stack.js
@@ -11,17 +11,17 @@
 
 const TAB_URL = EXAMPLE_URL + "doc_promise-get-rejection-stack.html";
 const { PromisesFront } = require("devtools/shared/fronts/promises");
 var EventEmitter = require("devtools/shared/event-emitter");
 
 // The code in the document above leaves an uncaught rejection. This is only
 // reported to the testing framework if the code is loaded in the main process.
 if (!gMultiProcessBrowser) {
-  Cu.import("resource://testing-common/PromiseTestUtils.jsm", this);
+  ChromeUtils.import("resource://testing-common/PromiseTestUtils.jsm", this);
   PromiseTestUtils.expectUncaughtRejection(/hello/);
 }
 
 const TEST_DATA = [
   {
     functionDisplayName: "returnPromise/<",
     line: 19,
     column: 47

--- a/devtools/client/debugger/test/mochitest/browser_dbg_sources-webext-contentscript.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_sources-webext-contentscript.js
@@ -5,17 +5,17 @@
 
 /**
  * Make sure eval scripts appear in the source list
  */
 
 const ADDON_PATH = "addon-webext-contentscript.xpi";
 const TAB_URL = EXAMPLE_URL + "doc_script_webext_contentscript.html";
 
-const {WebExtensionPolicy} = Cu.getGlobalForObject(Cu.import("resource://gre/modules/Extension.jsm", {}));
+const {WebExtensionPolicy} = Cu.getGlobalForObject(ChromeUtils.import("resource://gre/modules/Extension.jsm", {}));
 
 function test() {
   let gPanel, gDebugger;
   let gSources, gAddon;
 
   let cleanup = function* (e) {
     if (gAddon) {
       // Remove the addon, if any.

--- a/devtools/client/debugger/test/mochitest/browser_dbg_terminate-on-tab-close.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_terminate-on-tab-close.js
@@ -5,17 +5,17 @@
 
 /**
  * Tests that debuggee scripts are terminated on tab closure.
  */
 
 // The following rejection should not be left uncaught. This test has been
 // whitelisted until the issue is fixed.
 if (!gMultiProcessBrowser) {
-  Cu.import("resource://testing-common/PromiseTestUtils.jsm", this);
+  ChromeUtils.import("resource://testing-common/PromiseTestUtils.jsm", this);
   PromiseTestUtils.expectUncaughtRejection(/error\.message is undefined/);
 }
 
 const TAB_URL = EXAMPLE_URL + "doc_terminate-on-tab-close.html";
 
 function test() {
   let options = {
     source: TAB_URL,

--- a/devtools/client/debugger/test/mochitest/browser_dbg_worker-console-04.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_worker-console-04.js
@@ -2,17 +2,17 @@
 
 "use strict";
 
 // The following intermittent rejection should not be left uncaught. This test
 // has been whitelisted until the issue is fixed.
 //
 // NOTE: Whitelisting a class of rejections should be limited. Normally you
 //       should use "expectUncaughtRejection" to flag individual failures.
-Cu.import("resource://testing-common/PromiseTestUtils.jsm", this);
+ChromeUtils.import("resource://testing-common/PromiseTestUtils.jsm", this);
 PromiseTestUtils.whitelistRejectionsGlobally(/[object Object]/);
 
 const TAB_URL = EXAMPLE_URL + "doc_WorkerActor.attachThread-tab.html";
 const WORKER_URL = "code_WorkerActor.attachThread-worker.js";
 
 add_task(function* testPausedByConsole() {
   let {client, tab, workerClient, toolbox} =
     yield initWorkerDebugger(TAB_URL, WORKER_URL);

--- a/devtools/client/debugger/test/mochitest/browser_dbg_worker-window.js
+++ b/devtools/client/debugger/test/mochitest/browser_dbg_worker-window.js
@@ -1,16 +1,16 @@
 // Check to make sure that a worker can be attached to a toolbox
 // directly, and that the toolbox has expected properties.
 
 "use strict";
 
 // The following "connectionClosed" rejection should not be left uncaught. This
 // test has been whitelisted until the issue is fixed.
-Cu.import("resource://testing-common/PromiseTestUtils.jsm", this);
+ChromeUtils.import("resource://testing-common/PromiseTestUtils.jsm", this);
 PromiseTestUtils.expectUncaughtRejection(/[object Object]/);
 
 var TAB_URL = EXAMPLE_URL + "doc_WorkerActor.attachThread-tab.html";
 var WORKER_URL = "code_WorkerActor.attachThread-worker.js";
 
 add_task(function* () {
   yield pushPrefs(["devtools.scratchpad.enabled", true]);
 

--- a/devtools/client/debugger/test/mochitest/head.js
+++ b/devtools/client/debugger/test/mochitest/head.js
@@ -9,21 +9,21 @@
 Services.scriptloader.loadSubScript("chrome://mochitests/content/browser/devtools/client/framework/test/shared-head.js", this);
 
 // Disable logging for faster test runs. Set this pref to true if you want to
 // debug a test in your try runs. Both the debugger server and frontend will
 // 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 { BrowserToolboxProcess } = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
 var { DebuggerServer } = require("devtools/server/main");
 var { DebuggerClient } = require("devtools/shared/client/debugger-client");
 var ObjectClient = require("devtools/shared/client/object-client");
-var { AddonManager } = Cu.import("resource://gre/modules/AddonManager.jsm", {});
+var { AddonManager } = ChromeUtils.import("resource://gre/modules/AddonManager.jsm", {});
 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 = require("devtools/shared/deprecated-sync-thenables");
 

--- a/devtools/client/dom/main.js
+++ b/devtools/client/dom/main.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 { XPCOMUtils } = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
-const { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
+const { XPCOMUtils } = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm", {});
+const { BrowserLoader } = ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
 
 // Module Loader
 const require = BrowserLoader({
   baseURI: "resource://devtools/client/dom/",
   window
 }).require;
 
 XPCOMUtils.defineConstant(this, "require", require);

--- a/devtools/client/framework/ToolboxProcess.jsm
+++ b/devtools/client/framework/ToolboxProcess.jsm
@@ -4,18 +4,18 @@
  * 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 DBG_XUL = "chrome://devtools/content/framework/toolbox-process-window.xul";
 const CHROME_DEBUGGER_PROFILE_NAME = "chrome_debugger_profile";
 
-const { console } = Cu.import("resource://gre/modules/Console.jsm", {});
-const { require, DevToolsLoader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { console } = ChromeUtils.import("resource://gre/modules/Console.jsm", {});
+const { require, DevToolsLoader } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 
 ChromeUtils.defineModuleGetter(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/old-event-emitter");

--- a/devtools/client/framework/connect/connect.js
+++ b/devtools/client/framework/connect/connect.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 {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var Services = require("Services");
 var {gDevTools} = require("devtools/client/framework/devtools");
 var {TargetFactory} = require("devtools/client/framework/target");
 var {Toolbox} = require("devtools/client/framework/toolbox");
 var {DebuggerClient} = require("devtools/shared/client/debugger-client");
 var {Task} = require("devtools/shared/task");
 var {LocalizationHelper} = require("devtools/shared/l10n");
 var L10N = new LocalizationHelper("devtools/client/locales/connection-screen.properties");

--- a/devtools/client/framework/devtools.js
+++ b/devtools/client/framework/devtools.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 {Cu} = require("chrome");
 const Services = require("Services");
 
-const {DevToolsShim} = Cu.import("chrome://devtools-shim/content/DevToolsShim.jsm", {});
+const {DevToolsShim} = require("chrome://devtools-shim/content/DevToolsShim.jsm");
 
 // Load gDevToolsBrowser toolbox lazily as they need gDevTools to be fully initialized
 loader.lazyRequireGetter(this, "TargetFactory", "devtools/client/framework/target", true);
 loader.lazyRequireGetter(this, "TabTarget", "devtools/client/framework/target", true);
 loader.lazyRequireGetter(this, "Toolbox", "devtools/client/framework/toolbox", true);
 loader.lazyRequireGetter(this, "ToolboxHostManager", "devtools/client/framework/toolbox-host-manager", true);
 loader.lazyRequireGetter(this, "gDevToolsBrowser", "devtools/client/framework/devtools-browser", true);
 loader.lazyRequireGetter(this, "HUDService", "devtools/client/webconsole/hudservice", true);
@@ -138,17 +138,17 @@ DevTools.prototype = {
    *        cause a cascade of costly events
    */
   unregisterTool(tool, isQuitApplication) {
     let toolId = null;
     if (typeof tool == "string") {
       toolId = tool;
       tool = this._tools.get(tool);
     } else {
-      let {Deprecated} = Cu.import("resource://gre/modules/Deprecated.jsm", {});
+      let {Deprecated} = require("resource://gre/modules/Deprecated.jsm");
       Deprecated.warning("Deprecation WARNING: gDevTools.unregisterTool(tool) is " +
         "deprecated. You should unregister a tool using its toolId: " +
         "gDevTools.unregisterTool(toolId).");
       toolId = tool.id;
     }
     this._tools.delete(toolId);
 
     if (!isQuitApplication) {

--- a/devtools/client/framework/gDevTools.jsm
+++ b/devtools/client/framework/gDevTools.jsm
@@ -10,27 +10,27 @@
  * This JSM is here to keep some compatibility with existing add-ons.
  * Please now use the modules:
  * - devtools/client/framework/devtools for gDevTools
  * - devtools/client/framework/devtools-browser for gDevToolsBrowser
  */
 
 this.EXPORTED_SYMBOLS = [ "gDevTools", "gDevToolsBrowser" ];
 
-const { loader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { loader } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 /**
  * Do not directly map to the commonjs modules so that callsites of
  * gDevTools.jsm do not have to do anything to access to the very last version
  * of the module. The `devtools` and `browser` getter are always going to
  * retrieve the very last version of the modules.
  */
 Object.defineProperty(this, "require", {
   get() {
-    let { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+    let { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
     return require;
   }
 });
 Object.defineProperty(this, "devtools", {
   get() {
     return require("devtools/client/framework/devtools").gDevTools;
   }
 });

--- a/devtools/client/framework/test/browser_browser_toolbox.js
+++ b/devtools/client/framework/test/browser_browser_toolbox.js
@@ -42,17 +42,17 @@ add_task(function* runTest() {
       })
       .then(() => toolbox.destroy());
   };
   env.set("MOZ_TOOLBOX_TEST_SCRIPT", "new " + testScript);
   registerCleanupFunction(() => {
     env.set("MOZ_TOOLBOX_TEST_SCRIPT", "");
   });
 
-  let { BrowserToolboxProcess } = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
+  let { BrowserToolboxProcess } = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
   let closePromise;
   yield new Promise(onRun => {
     closePromise = new Promise(onClose => {
       info("Opening the browser toolbox\n");
       BrowserToolboxProcess.init(onClose, onRun);
     });
   });
   ok(true, "Browser toolbox started\n");

--- a/devtools/client/framework/test/browser_browser_toolbox_debugger.js
+++ b/devtools/client/framework/test/browser_browser_toolbox_debugger.js
@@ -79,24 +79,24 @@ add_task(function* runTest() {
       } else {
         msg = "SUCCESS: " + msg;
         dump(msg + "\n");
       }
     };
 
     const registerCleanupFunction = () => {};
 
-    const { Task } = Cu.import("resource://gre/modules/Task.jsm", {});
-    const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
-    const { Services } = Cu.import("resource://gre/modules/Services.jsm", {});
+    const { Task } = ChromeUtils.import("resource://gre/modules/Task.jsm", {});
+    const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
+    const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm", {});
 
     // Copied from shared-head.js:
     // test_browser_toolbox_debugger.js uses waitForPaused, which relies on waitUntil
     // which is normally provided by shared-head.js
-    const { setTimeout } = Cu.import("resource://gre/modules/Timer.jsm", {});
+    const { setTimeout } = ChromeUtils.import("resource://gre/modules/Timer.jsm", {});
     function waitUntil(predicate, interval = 10) {
       if (predicate()) {
         return Promise.resolve(true);
       }
       return new Promise(resolve => {
         setTimeout(function () {
           waitUntil(predicate, interval).then(() => resolve(true));
         }, interval);
@@ -121,17 +121,17 @@ add_task(function* runTest() {
     "  dump('Exception: '+ e + ' at ' + e.fileName + ':' + " +
     "       e.lineNumber + '\\nStack: ' + e.stack + '\\n');" +
     "}";
   env.set("MOZ_TOOLBOX_TEST_SCRIPT", source);
   registerCleanupFunction(() => {
     env.set("MOZ_TOOLBOX_TEST_SCRIPT", "");
   });
 
-  let { BrowserToolboxProcess } = Cu.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
+  let { BrowserToolboxProcess } = ChromeUtils.import("resource://devtools/client/framework/ToolboxProcess.jsm", {});
   // Use two promises, one for each BrowserToolboxProcess.init callback
   // arguments, to ensure that we wait for toolbox run and close events.
   let closePromise;
   yield new Promise(onRun => {
     closePromise = new Promise(onClose => {
       info("Opening the browser toolbox\n");
       BrowserToolboxProcess.init(onClose, onRun);
     });

--- a/devtools/client/framework/test/browser_target_from_url.js
+++ b/devtools/client/framework/test/browser_target_from_url.js
@@ -1,15 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 const TEST_URI = "data:text/html;charset=utf-8," +
   "<p>browser_target-from-url.js</p>";
 
-const { DevToolsLoader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { DevToolsLoader } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const { targetFromURL } = require("devtools/client/framework/target-from-url");
 
 Services.prefs.setBoolPref("devtools.debugger.remote-enabled", true);
 Services.prefs.setBoolPref("devtools.debugger.prompt-connection", false);
 
 SimpleTest.registerCleanupFunction(() => {
   Services.prefs.clearUserPref("devtools.debugger.remote-enabled");
   Services.prefs.clearUserPref("devtools.debugger.prompt-connection");

--- a/devtools/client/framework/test/shared-head.js
+++ b/devtools/client/framework/test/shared-head.js
@@ -10,17 +10,17 @@
 // devtools.
 // It contains various common helper functions.
 
 const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr, Constructor: CC}
   = Components;
 
 function scopedCuImport(path) {
   const scope = {};
-  Cu.import(path, scope);
+  ChromeUtils.import(path, scope);
   return scope;
 }
 
 // There are shutdown issues for which multiple rejections are left uncaught.
 // This bug should be fixed, but for the moment devtools are whitelisted.
 //
 // NOTE: Entire directory whitelisting should be kept to a minimum. Normally you
 //       should use "expectUncaughtRejection" to flag individual failures.
@@ -691,17 +691,17 @@ function waitForTitleChange(toolbox) {
  * The server can be accessed like:
  *
  *   const server = createTestHTTPServer();
  *   let url = "http://localhost: " + server.identity.primaryPort + "/path";
  *
  * @returns {HttpServer}
  */
 function createTestHTTPServer() {
-  const {HttpServer} = Cu.import("resource://testing-common/httpd.js", {});
+  const {HttpServer} = ChromeUtils.import("resource://testing-common/httpd.js", {});
   let server = new HttpServer();
 
   registerCleanupFunction(function* cleanup() {
     let destroyed = defer();
     server.stop(() => {
       destroyed.resolve();
     });
     yield destroyed.promise;

--- a/devtools/client/framework/toolbox-init.js
+++ b/devtools/client/framework/toolbox-init.js
@@ -8,17 +8,17 @@
 "use strict";
 
 // URL constructor doesn't support about: scheme
 let href = window.location.href.replace("about:", "http://");
 let url = new window.URL(href);
 
 // Only use this method to attach the toolbox if some query parameters are given
 if (url.search.length > 1) {
-  const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+  const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
   const { gDevTools } = require("devtools/client/framework/devtools");
   const { targetFromURL } = require("devtools/client/framework/target-from-url");
   const { Toolbox } = require("devtools/client/framework/toolbox");
   const { TargetFactory } = require("devtools/client/framework/target");
   const { DebuggerServer } = require("devtools/server/main");
   const { DebuggerClient } = require("devtools/shared/client/debugger-client");
   const { Task } = require("devtools/shared/task");
 

--- a/devtools/client/framework/toolbox-process-window.js
+++ b/devtools/client/framework/toolbox-process-window.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 { loader, require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { loader, require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 // Require this module to setup core modules
 loader.require("devtools/client/framework/devtools-browser");
 
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { TargetFactory } = require("devtools/client/framework/target");
 var { Toolbox } = require("devtools/client/framework/toolbox");
 var Services = require("Services");
 var { DebuggerClient } = require("devtools/shared/client/debugger-client");

--- a/devtools/client/inspector/grids/test/unit/head.js
+++ b/devtools/client/inspector/grids/test/unit/head.js
@@ -1,8 +1,8 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
 
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});

--- a/devtools/client/inspector/markup/test/browser_markup_links_06.js
+++ b/devtools/client/inspector/markup/test/browser_markup_links_06.js
@@ -4,17 +4,17 @@
 
 "use strict";
 
 // Tests that the contextual menu items shown when clicking on linked attributes
 // for <script> and <link> tags actually open the right tools.
 
 // The following rejection should not be left uncaught. This test has been
 // whitelisted until the issue is fixed.
-Cu.import("resource://testing-common/PromiseTestUtils.jsm", this);
+ChromeUtils.import("resource://testing-common/PromiseTestUtils.jsm", this);
 PromiseTestUtils.expectUncaughtRejection(/NS_ERROR_NOT_INITIALIZED/);
 
 const TEST_URL = URL_ROOT + "doc_markup_links.html";
 
 add_task(function* () {
   let {toolbox, inspector} = yield openInspectorForURL(TEST_URL);
 
   info("Select a node with a cssresource attribute");

--- a/devtools/client/inspector/markup/test/browser_markup_mutation_02.js
+++ b/devtools/client/inspector/markup/test/browser_markup_mutation_02.js
@@ -3,17 +3,17 @@
  http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 // Test that markup-containers in the markup-view do flash when their
 // corresponding DOM nodes mutate
 
 // Have to use the same timer functions used by the inspector.
-const {clearTimeout} = Cu.import("resource://gre/modules/Timer.jsm", {});
+const {clearTimeout} = ChromeUtils.import("resource://gre/modules/Timer.jsm", {});
 
 const TEST_URL = URL_ROOT + "doc_markup_flashing.html";
 
 // The test data contains a list of mutations to test.
 // Each item is an object:
 // - desc: a description of the test step, for better logging
 // - mutate: a generator function that should make changes to the content DOM
 // - attribute: if set, the test will expect the corresponding attribute to

--- a/devtools/client/jsonview/converter-child.js
+++ b/devtools/client/jsonview/converter-child.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, CC} = require("chrome");
-const { XPCOMUtils } = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
+const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
 const Services = require("Services");
 
 loader.lazyRequireGetter(this, "NetworkHelper",
                                "devtools/shared/webconsole/network-helper");
 loader.lazyGetter(this, "debug", function () {
   let {AppConstants} = require("resource://gre/modules/AppConstants.jsm");
   return !!(AppConstants.DEBUG || AppConstants.DEBUG_JS_MODULES);
 });

--- a/devtools/client/jsonview/converter-observer.js
+++ b/devtools/client/jsonview/converter-observer.js
@@ -3,22 +3,22 @@
 /* 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 Cm = Components.manager;
 
-const {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
-const {Services} = Cu.import("resource://gre/modules/Services.jsm", {});
+const {XPCOMUtils} = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm", {});
+const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm", {});
 
 // Load devtools module lazily.
 XPCOMUtils.defineLazyGetter(this, "devtools", function () {
-  const {devtools} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+  const {devtools} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
   return devtools;
 });
 
 // Load JsonView services lazily.
 XPCOMUtils.defineLazyGetter(this, "JsonViewService", function () {
   const {JsonViewService} = devtools.require("devtools/client/jsonview/converter-child");
   return JsonViewService;
 });

--- a/devtools/client/memory/initializer.js
+++ b/devtools/client/memory/initializer.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/. */
 
 /* exported initialize, destroy, Promise */
 
 "use strict";
 
 const BrowserLoaderModule = {};
-Cu.import("resource://devtools/client/shared/browser-loader.js", BrowserLoaderModule);
+ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", BrowserLoaderModule);
 const { require } = BrowserLoaderModule.BrowserLoader({
   baseURI: "resource://devtools/client/memory/",
   window
 });
 const { Task } = require("devtools/shared/task");
 const { createFactory, createElement } = require("devtools/client/shared/vendor/react");
 const ReactDOM = require("devtools/client/shared/vendor/react-dom");
 const { Provider } = require("devtools/client/shared/vendor/react-redux");

--- a/devtools/client/memory/test/chrome/head.js
+++ b/devtools/client/memory/test/chrome/head.js
@@ -1,14 +1,14 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-var { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
+var { BrowserLoader } = ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
 var { require } = BrowserLoader({
   baseURI: "resource://devtools/client/memory/",
   window
 });
 var { Assert } = require("resource://testing-common/Assert.jsm");
 var Services = require("Services");
 var { Task } = require("devtools/shared/task");
 

--- a/devtools/client/memory/test/unit/head.js
+++ b/devtools/client/memory/test/unit/head.js
@@ -1,15 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-var { console } = Cu.import("resource://gre/modules/Console.jsm", {});
-var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { console } = ChromeUtils.import("resource://gre/modules/Console.jsm", {});
+var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 var Services = require("Services");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var flags = require("devtools/shared/flags");
 flags.testing = true;
 flags.wantLogging = true;
 flags.wantVerbose = false;
 

--- a/devtools/client/netmonitor/test/browser_net_simple-request-data.js
+++ b/devtools/client/netmonitor/test/browser_net_simple-request-data.js
@@ -7,17 +7,17 @@
  * Tests if requests render correct information in the menu UI.
  */
 
 // The following intermittent rejections should not be left uncaught. This test
 // has been whitelisted until the issue is fixed.
 //
 // NOTE: Whitelisting a class of rejections should be limited. Normally you
 //       should use "expectUncaughtRejection" to flag individual failures.
-Cu.import("resource://testing-common/PromiseTestUtils.jsm", this);
+ChromeUtils.import("resource://testing-common/PromiseTestUtils.jsm", this);
 PromiseTestUtils.whitelistRejectionsGlobally(/cookies is undefined/);
 PromiseTestUtils.whitelistRejectionsGlobally(/requestItem is undefined/);
 
 function test() {
   // Disable tcp fast open, because it is setting a response header indicator
   // (bug 1352274). TCP Fast Open is not present on all platforms therefore the
   // number of response headers will vary depending on the platform.
   Services.prefs.setBoolPref("network.tcp.tcp_fastopen_enable", false);

--- a/devtools/client/netmonitor/test/unit/test_mdn-utils.js
+++ b/devtools/client/netmonitor/test/unit/test_mdn-utils.js
@@ -1,17 +1,17 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test for mdn-utils
 
 "use strict";
 
 function run_test() {
-  const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+  const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
   const MDN_URL = "https://developer.mozilla.org/docs/";
   const GTM_PARAMS_NM = "?utm_source=mozilla" +
     "&utm_medium=devtools-netmonitor&utm_campaign=default";
   const GTM_PARAMS_WC = "?utm_source=mozilla" +
     "&utm_medium=devtools-webconsole&utm_campaign=default";
 
   const {
     getHeadersURL,

--- a/devtools/client/performance/components/test/head.js
+++ b/devtools/client/performance/components/test/head.js
@@ -1,19 +1,19 @@
 /* Any copyright is dedicated to the Public Domain.
     yield new Promise(function(){});
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 /* global window, document, SimpleTest, requestAnimationFrame, is, ok */
 /* exported Cc, Ci, Cu, Cr, Assert, Task, TargetFactory, Toolbox, browserRequire,
    forceRender, setProps, dumpn, checkOptimizationHeader, checkOptimizationTree */
-let { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+let { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 let { Assert } = require("resource://testing-common/Assert.jsm");
-let { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
+let { BrowserLoader } = ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
 let defer = require("devtools/shared/defer");
 let flags = require("devtools/shared/flags");
 let { Task } = require("devtools/shared/task");
 let { TargetFactory } = require("devtools/client/framework/target");
 let { Toolbox } = require("devtools/client/framework/toolbox");
 
 flags.testing = true;
 let { require: browserRequire } = BrowserLoader({

--- a/devtools/client/performance/performance-controller.js
+++ b/devtools/client/performance/performance-controller.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";
 
 /* globals window, document, PerformanceView, ToolbarView, RecordingsView, DetailsView */
 
 /* exported Cc, Ci, Cu, Cr, loader, Promise */
 var BrowserLoaderModule = {};
-Cu.import("resource://devtools/client/shared/browser-loader.js", BrowserLoaderModule);
+ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", BrowserLoaderModule);
 var { loader, require } = BrowserLoaderModule.BrowserLoader({
   baseURI: "resource://devtools/client/performance/",
   window
 });
 var { Task } = require("devtools/shared/task");
 /* exported ViewHelpers, WidgetMethods, setNamedTimeout, clearNamedTimeout */
 var { ViewHelpers, WidgetMethods, setNamedTimeout, clearNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 var { PrefObserver } = require("devtools/client/shared/prefs");

--- a/devtools/client/performance/test/browser_perf-recordings-io-03.js
+++ b/devtools/client/performance/test/browser_perf-recordings-io-03.js
@@ -2,18 +2,18 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 /* eslint-disable */
 /**
  * Tests if the performance tool gracefully handles loading files that are JSON,
  * but don't contain the appropriate recording data.
  */
 
-var { FileUtils } = Cu.import("resource://gre/modules/FileUtils.jsm", {});
-var { NetUtil } = Cu.import("resource://gre/modules/NetUtil.jsm", {});
+var { FileUtils } = ChromeUtils.import("resource://gre/modules/FileUtils.jsm", {});
+var { NetUtil } = ChromeUtils.import("resource://gre/modules/NetUtil.jsm", {});
 
 var test = Task.async(function* () {
   let { target, panel, toolbox } = yield initPerformance(SIMPLE_URL);
   let { EVENTS, PerformanceController } = panel.panelWin;
 
   let file = FileUtils.getFile("TmpD", ["tmpprofile.json"]);
   file.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, parseInt("666", 8));
   yield asyncCopy({ bogus: "data" }, file);

--- a/devtools/client/performance/test/head.js
+++ b/devtools/client/performance/test/head.js
@@ -1,13 +1,13 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
-const { require, loader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require, loader } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 /* exported loader, either, click, dblclick, mousedown, rightMousedown, key */
 // All tests are asynchronous.
 waitForExplicitFinish();
 
 // Performance tests are much heavier because of their reliance on the
 // profiler module, memory measurements, frequent canvas operations etc. Many of
 // of them take longer than 30 seconds to finish on try server VMs, even though

--- a/devtools/client/performance/test/unit/head.js
+++ b/devtools/client/performance/test/unit/head.js
@@ -1,14 +1,14 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 /* exported Cc, Ci, Cu, Cr, Services, console, PLATFORM_DATA_PREF, getFrameNodePath,
    synthesizeProfileForTest */
-var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var Services = require("Services");
 var { console } = require("resource://gre/modules/Console.jsm");
 const RecordingUtils = require("devtools/shared/performance/recording-utils");
 const PLATFORM_DATA_PREF = "devtools.performance.ui.show-platform-data";
 
 /**
  * Get a path in a FrameNode call tree.
  */

--- a/devtools/client/responsive.html/index.js
+++ b/devtools/client/responsive.html/index.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/. */
 
 /* eslint-env browser */
 
 "use strict";
 
 const { BrowserLoader } =
-  Cu.import("resource://devtools/client/shared/browser-loader.js", {});
+  ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
 const { require } = BrowserLoader({
   baseURI: "resource://devtools/client/responsive.html/",
   window
 });
 const Telemetry = require("devtools/client/shared/telemetry");
 const { loadAgentSheet } = require("./utils/css");
 
 const { createFactory, createElement } =

--- a/devtools/client/responsive.html/test/browser/browser_hide_container.js
+++ b/devtools/client/responsive.html/test/browser/browser_hide_container.js
@@ -4,17 +4,17 @@
 "use strict";
 
 // Ensure that the RDM container tab URL is not recorded in session history.
 
 const TEST_URL = "http://example.com/";
 const CONTAINER_URL = "chrome://devtools/content/responsive.html/index.xhtml";
 
 const { TabStateFlusher } =
-  Cu.import("resource:///modules/sessionstore/TabStateFlusher.jsm", {});
+  ChromeUtils.import("resource:///modules/sessionstore/TabStateFlusher.jsm", {});
 const SessionStore =
   Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
 const { OUTER_FRAME_LOADER_SYMBOL } =
   require("devtools/client/responsive.html/browser/tunnel");
 
 function flushContainerTabState(tab) {
   let browser = tab.linkedBrowser;
   let outerBrowser = {

--- a/devtools/client/responsive.html/test/browser/browser_toolbox_swap_browsers.js
+++ b/devtools/client/responsive.html/test/browser/browser_toolbox_swap_browsers.js
@@ -5,17 +5,17 @@
 
 // Verify that toolbox remains open when opening and closing RDM.
 
 const TEST_URL = "http://example.com/";
 
 function getServerConnections(browser) {
   ok(browser.isRemoteBrowser, "Content browser is remote");
   return ContentTask.spawn(browser, {}, async function () {
-    const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+    const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
     const { DebuggerServer } = require("devtools/server/main");
     if (!DebuggerServer._connections) {
       return 0;
     }
     return Object.getOwnPropertyNames(DebuggerServer._connections);
   });
 }
 

--- a/devtools/client/responsive.html/test/browser/head.js
+++ b/devtools/client/responsive.html/test/browser/head.js
@@ -273,17 +273,17 @@ const selectNetworkThrottling = (ui, val
   once(ui, "network-throttling-changed"),
   changeSelectValue(ui, "#global-network-throttling-selector", value)
 ]);
 
 function getSessionHistory(browser) {
   return ContentTask.spawn(browser, {}, async function () {
     /* eslint-disable no-undef */
     const { SessionHistory } =
-      Cu.import("resource://gre/modules/sessionstore/SessionHistory.jsm", {});
+      ChromeUtils.import("resource://gre/modules/sessionstore/SessionHistory.jsm", {});
     return SessionHistory.collect(docShell);
     /* eslint-enable no-undef */
   });
 }
 
 function getContentSize(ui) {
   return spawnViewportTask(ui, {}, () => ({
     width: content.screen.width,

--- a/devtools/client/responsive.html/test/unit/head.js
+++ b/devtools/client/responsive.html/test/unit/head.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
 
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 const promise = require("promise");
 const Store = require("devtools/client/responsive.html/store");
 
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 
 const flags = require("devtools/shared/flags");
 flags.testing = true;

--- a/devtools/client/scratchpad/scratchpad-commands.js
+++ b/devtools/client/scratchpad/scratchpad-commands.js
@@ -11,12 +11,12 @@ exports.items = [{
   item: "command",
   runAt: "client",
   name: "scratchpad",
   buttonId: "command-button-scratchpad",
   buttonClass: "command-button",
   tooltipText: l10n.lookup("scratchpadOpenTooltip"),
   hidden: true,
   exec: function (args, context) {
-    const {ScratchpadManager} = Cu.import("resource://devtools/client/scratchpad/scratchpad-manager.jsm", {});
+    const {ScratchpadManager} = require("resource://devtools/client/scratchpad/scratchpad-manager.jsm");
     ScratchpadManager.openScratchpad();
   }
 }];

--- a/devtools/client/scratchpad/scratchpad-manager.jsm
+++ b/devtools/client/scratchpad/scratchpad-manager.jsm
@@ -5,17 +5,17 @@
 
 "use strict";
 
 this.EXPORTED_SYMBOLS = ["ScratchpadManager"];
 
 const SCRATCHPAD_WINDOW_URL = "chrome://devtools/content/scratchpad/scratchpad.xul";
 const SCRATCHPAD_WINDOW_FEATURES = "chrome,titlebar,toolbar,centerscreen,resizable,dialog=no";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const Services = require("Services");
 const Telemetry = require("devtools/client/shared/telemetry");
 
 
 /**
  * The ScratchpadManager object opens new Scratchpad windows and manages the state
  * of open scratchpads for session restore. There's only one ScratchpadManager in
  * the life of the browser.

--- a/devtools/client/scratchpad/scratchpad.js
+++ b/devtools/client/scratchpad/scratchpad.js
@@ -34,17 +34,17 @@ const WRAP_TEXT = "devtools.scratchpad.w
 const SHOW_TRAILING_SPACE = "devtools.scratchpad.showTrailingSpace";
 const EDITOR_FONT_SIZE = "devtools.scratchpad.editorFontSize";
 const ENABLE_AUTOCOMPLETION = "devtools.scratchpad.enableAutocompletion";
 const TAB_SIZE = "devtools.editor.tabsize";
 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 {require, loader} = ChromeUtils.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/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");

--- a/devtools/client/scratchpad/test/browser_scratchpad_confirm_close.js
+++ b/devtools/client/scratchpad/test/browser_scratchpad_confirm_close.js
@@ -1,16 +1,16 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 /* Bug 653427 */
 
 var tempScope = {};
-Cu.import("resource://gre/modules/NetUtil.jsm", tempScope);
-Cu.import("resource://gre/modules/FileUtils.jsm", tempScope);
+ChromeUtils.import("resource://gre/modules/NetUtil.jsm", tempScope);
+ChromeUtils.import("resource://gre/modules/FileUtils.jsm", tempScope);
 var NetUtil = tempScope.NetUtil;
 var FileUtils = tempScope.FileUtils;
 
 // only finish() when correct number of tests are done
 const expected = 9;
 var count = 0;
 function done()
 {

--- a/devtools/client/scratchpad/test/browser_scratchpad_sessions.js
+++ b/devtools/client/scratchpad/test/browser_scratchpad_sessions.js
@@ -1,13 +1,13 @@
  /* Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
-const {Utils} = Cu.import("resource://gre/modules/sessionstore/Utils.jsm", {});
+const {Utils} = ChromeUtils.import("resource://gre/modules/sessionstore/Utils.jsm", {});
 const triggeringPrincipal_base64 = Utils.SERIALIZED_SYSTEMPRINCIPAL;
 const ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
 
 const testState = {
   windows: [{
     tabs: [
       { entries: [{ url: "about:blank", triggeringPrincipal_base64 }] },
     ]

--- a/devtools/client/scratchpad/test/browser_scratchpad_wrong_window_focus.js
+++ b/devtools/client/scratchpad/test/browser_scratchpad_wrong_window_focus.js
@@ -24,17 +24,17 @@ function test()
   // Then we wait for our message to appear in the console and click
   // on the location link. After that we check which Scratchpad window
   // is currently active (it should be the older one).
 
   gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser);
   BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser).then(function () {
     openScratchpad(function () {
       let sw = gScratchpadWindow;
-      let {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+      let {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
       let {TargetFactory} = require("devtools/client/framework/target");
 
       openScratchpad(function () {
         let target = TargetFactory.forTab(gBrowser.selectedTab);
         gDevTools.showToolbox(target, "webconsole").then((toolbox) => {
           let hud = toolbox.getCurrentPanel().hud;
           hud.jsterm.clearOutput(true);
           testFocus(sw, hud);

--- a/devtools/client/scratchpad/test/head.js
+++ b/devtools/client/scratchpad/test/head.js
@@ -1,19 +1,19 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {NetUtil} = Cu.import("resource://gre/modules/NetUtil.jsm", {});
-const {FileUtils} = Cu.import("resource://gre/modules/FileUtils.jsm", {});
-const {console} = Cu.import("resource://gre/modules/Console.jsm", {});
-const {ScratchpadManager} = Cu.import("resource://devtools/client/scratchpad/scratchpad-manager.jsm", {});
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {NetUtil} = ChromeUtils.import("resource://gre/modules/NetUtil.jsm", {});
+const {FileUtils} = ChromeUtils.import("resource://gre/modules/FileUtils.jsm", {});
+const {console} = ChromeUtils.import("resource://gre/modules/Console.jsm", {});
+const {ScratchpadManager} = ChromeUtils.import("resource://devtools/client/scratchpad/scratchpad-manager.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {gDevTools} = require("devtools/client/framework/devtools");
 const Services = require("Services");
 const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const flags = require("devtools/shared/flags");
 const promise = require("promise");
 const defer = require("devtools/shared/defer");
 
 

--- a/devtools/client/shadereditor/shadereditor.js
+++ b/devtools/client/shadereditor/shadereditor.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 {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.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 defer = require("devtools/shared/defer");
 const Services = require("Services");
 const EventEmitter = require("devtools/shared/old-event-emitter");
 const Tooltip = require("devtools/client/shared/widgets/tooltip/Tooltip");
 const Editor = require("devtools/client/sourceeditor/editor");

--- a/devtools/client/shadereditor/test/head.js
+++ b/devtools/client/shadereditor/test/head.js
@@ -1,13 +1,13 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
-var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var { Task } = require("devtools/shared/task");
 
 var Services = require("Services");
 var promise = require("promise");
 const defer = require("devtools/shared/defer");
 var { gDevTools } = require("devtools/client/framework/devtools");
 var { DebuggerClient } = require("devtools/shared/client/debugger-client");
 var { DebuggerServer } = require("devtools/server/main");

--- a/devtools/client/shared/AppCacheUtils.jsm
+++ b/devtools/client/shared/AppCacheUtils.jsm
@@ -20,19 +20,19 @@
  *  - Too many dot dot slash operators
  *  - SETTINGS section is valid
  *  - Invalid section name
  *  - etc.
  */
 
 "use strict";
 
-var { XPCOMUtils } = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
-var { NetUtil } = Cu.import("resource://gre/modules/NetUtil.jsm", {});
-var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { XPCOMUtils } = ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm", {});
+var { NetUtil } = ChromeUtils.import("resource://gre/modules/NetUtil.jsm", {});
+var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 var { gDevTools } = require("devtools/client/framework/devtools");
 var Services = require("Services");
 var promise = require("promise");
 
 this.EXPORTED_SYMBOLS = ["AppCacheUtils"];
 
 function AppCacheUtils(documentOrUri) {

--- a/devtools/client/shared/DOMHelpers.jsm
+++ b/devtools/client/shared/DOMHelpers.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 { Services } = Cu.import("resource://gre/modules/Services.jsm", {});
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const nodeFilterConstants = require("devtools/shared/dom-node-filter-constants");
 
 this.EXPORTED_SYMBOLS = ["DOMHelpers"];
 
 /**
  * DOMHelpers
  * Makes DOM traversal easier. Goes through iframes.
  *

--- a/devtools/client/shared/SplitView.jsm
+++ b/devtools/client/shared/SplitView.jsm
@@ -1,16 +1,16 @@
 /* vim:set ts=2 sw=2 sts=2 et: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {KeyCodes} = require("devtools/client/shared/keycodes");
 
 this.EXPORTED_SYMBOLS = ["SplitView"];
 
 /* this must be kept in sync with CSS (ie. splitview.css) */
 const LANDSCAPE_MEDIA_QUERY = "(min-width: 701px)";
 
 var bindings = new WeakMap();

--- a/devtools/client/shared/browser-loader.js
+++ b/devtools/client/shared/browser-loader.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 loaders = Cu.import("resource://devtools/shared/base-loader.js", {});
-const { devtools } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const loaders = ChromeUtils.import("resource://devtools/shared/base-loader.js", {});
+const { devtools } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const { joinURI } = devtools.require("devtools/shared/path");
 const { assert } = devtools.require("devtools/shared/DevToolsUtils");
 const { AppConstants } = devtools.require("resource://gre/modules/AppConstants.jsm");
 
 const BROWSER_BASED_DIRS = [
   "resource://devtools/client/inspector/boxmodel",
   "resource://devtools/client/inspector/changes",
   "resource://devtools/client/inspector/computed",

--- a/devtools/client/shared/components/test/mochitest/head.js
+++ b/devtools/client/shared/components/test/mochitest/head.js
@@ -1,19 +1,19 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /* eslint no-unused-vars: [2, {"vars": "local"}] */
 
 "use strict";
 
-var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var { Assert } = require("resource://testing-common/Assert.jsm");
 var { gDevTools } = require("devtools/client/framework/devtools");
-var { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
+var { BrowserLoader } = ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
 var promise = require("promise");
 var defer = require("devtools/shared/defer");
 var Services = require("Services");
 var { DebuggerServer } = require("devtools/server/main");
 var { DebuggerClient } = require("devtools/shared/client/debugger-client");
 var DevToolsUtils = require("devtools/shared/DevToolsUtils");
 var flags = require("devtools/shared/flags");
 var { Task } = require("devtools/shared/task");

--- a/devtools/client/shared/frame-script-utils.js
+++ b/devtools/client/shared/frame-script-utils.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/. */
 
 /* eslint-env browser */
 /* global addMessageListener, sendAsyncMessage, content */
 "use strict";
-const {require, loader} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require, loader} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const { Task } = require("devtools/shared/task");
 
 loader.lazyGetter(this, "nsIProfilerModule", () => {
   return Cc["@mozilla.org/tools/profiler;1"].getService(Ci.nsIProfiler);
 });
 
 addMessageListener("devtools:test:history", function ({ data }) {
   content.history[data.direction]();

--- a/devtools/client/shared/test/browser_layoutHelpers-getBoxQuads.js
+++ b/devtools/client/shared/test/browser_layoutHelpers-getBoxQuads.js
@@ -43,17 +43,17 @@ add_task(async function () {
         });
       });
       sendAsyncMessage("devtools-test:command", cmd);
       return onDone;
     }
 
     const doc = content.document;
 
-    const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+    const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
     const {getAdjustedQuads} = require("devtools/shared/layout/utils");
 
     ok(typeof getAdjustedQuads === "function", "getAdjustedQuads is defined");
 
     returnsTheRightDataStructure();
     isEmptyForMissingNode();
     isEmptyForHiddenNodes();
     defaultsToBorderBoxIfNoneProvided();

--- a/devtools/client/shared/test/browser_require_raw.js
+++ b/devtools/client/shared/test/browser_require_raw.js
@@ -1,16 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const { BrowserLoader } = Cu.import("resource://devtools/client/shared/browser-loader.js", {});
+const { BrowserLoader } = ChromeUtils.import("resource://devtools/client/shared/browser-loader.js", {});
 
 const { require: browserRequire } = BrowserLoader({
   baseURI: "resource://devtools/client/shared/",
   window
 });
 
 const variableFileContents = browserRequire("raw!devtools/client/themes/variables.css");
 

--- a/devtools/client/shared/test/head.js
+++ b/devtools/client/shared/test/head.js
@@ -4,17 +4,17 @@
 /* eslint no-unused-vars: [2, {"vars": "local", "args": "none"}] */
 /* import-globals-from ../../framework/test/shared-head.js */
 
 "use strict";
 
 // 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 {DOMHelpers} = Cu.import("resource://devtools/client/shared/DOMHelpers.jsm", {});
+const {DOMHelpers} = ChromeUtils.import("resource://devtools/client/shared/DOMHelpers.jsm", {});
 const {Hosts} = require("devtools/client/framework/toolbox-hosts");
 
 const TEST_URI_ROOT = "http://example.com/browser/devtools/client/shared/test/";
 const OPTIONS_VIEW_URL = TEST_URI_ROOT + "doc_options-view.xul";
 
 function catchFail(func) {
   return function () {
     try {

--- a/devtools/client/shared/test/test-actor-registry.js
+++ b/devtools/client/shared/test/test-actor-registry.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";
 
 (function (exports) {
   const CC = Components.Constructor;
 
-  const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+  const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
   const { fetch } = require("devtools/shared/DevToolsUtils");
   const { Task } = require("devtools/shared/task");
 
   const TEST_URL_ROOT = "http://example.com/browser/devtools/client/shared/test/";
   const ACTOR_URL = TEST_URL_ROOT + "test-actor.js";
 
   // Register a test actor that can operate on the remote document
   exports.registerTestActor = Task.async(function* (client) {

--- a/devtools/client/shared/test/unit/test_VariablesView_filtering-without-controller.js
+++ b/devtools/client/shared/test/unit/test_VariablesView_filtering-without-controller.js
@@ -6,17 +6,17 @@
 "use strict";
 
 // Test that VariablesView._doSearch() works even without an attached
 // VariablesViewController (bug 1196341).
 
 const DOMParser = Cc["@mozilla.org/xmlextras/domparser;1"]
                     .createInstance(Ci.nsIDOMParser);
 const { VariablesView } =
-  Cu.import("resource://devtools/client/shared/widgets/VariablesView.jsm", {});
+  ChromeUtils.import("resource://devtools/client/shared/widgets/VariablesView.jsm", {});
 
 function run_test() {
   let doc = DOMParser.parseFromString("<div>", "text/html");
   let container = doc.body.firstChild;
   ok(container, "Got a container.");
 
   let vv = new VariablesView(container, { searchEnabled: true });
   let scope = vv.addScope("Test scope");

--- a/devtools/client/shared/test/unit/test_advanceValidate.js
+++ b/devtools/client/shared/test/unit/test_advanceValidate.js
@@ -2,17 +2,17 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 // Tests the advanceValidate function from rule-view.js.
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {advanceValidate} = require("devtools/client/inspector/shared/utils");
 
 //                            1         2         3
 //                  0123456789012345678901234567890
 const sampleInput = '\\symbol "string" url(somewhere)';
 
 function testInsertion(where, result, testName) {
   info(testName);

--- a/devtools/client/shared/test/unit/test_bezierCanvas.js
+++ b/devtools/client/shared/test/unit/test_bezierCanvas.js
@@ -2,17 +2,17 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 // Tests the BezierCanvas API in the CubicBezierWidget module
 
-var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var {CubicBezier, BezierCanvas} = require("devtools/client/shared/widgets/CubicBezierWidget");
 
 function run_test() {
   offsetsGetterReturnsData();
   convertsOffsetsToCoordinates();
   plotsCanvas();
 }
 

--- a/devtools/client/shared/test/unit/test_cssAngle.js
+++ b/devtools/client/shared/test/unit/test_cssAngle.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test classifyAngle.
 
 "use strict";
 
-var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 const {angleUtils} = require("devtools/client/shared/css-angle");
 
 const CLASSIFY_TESTS = [
   { input: "180deg", output: "deg" },
   { input: "-180deg", output: "deg" },
   { input: "180DEG", output: "deg" },
   { input: "200rad", output: "rad" },

--- a/devtools/client/shared/test/unit/test_cssColor-01.js
+++ b/devtools/client/shared/test/unit/test_cssColor-01.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test classifyColor.
 
 "use strict";
 
-var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {colorUtils} = require("devtools/shared/css/color");
 const InspectorUtils = require("InspectorUtils");
 
 const CLASSIFY_TESTS = [
   { input: "rgb(255,0,192)", output: "rgb" },
   { input: "RGB(255,0,192)", output: "rgb" },
   { input: "RGB(100%,0%,83%)", output: "rgb" },
   { input: "rgba(255,0,192, 0.25)", output: "rgb" },

--- a/devtools/client/shared/test/unit/test_cssColor-03.js
+++ b/devtools/client/shared/test/unit/test_cssColor-03.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test css-color-4 color function syntax and old-style syntax.
 
 "use strict";
 
-var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {colorUtils} = require("devtools/shared/css/color");
 const InspectorUtils = require("InspectorUtils");
 
 const OLD_STYLE_TESTS = [
   "rgb(255,0,192)",
   "RGB(255,0,192)",
   "RGB(100%,0%,83%)",
   "rgba(255,0,192,0.25)",

--- a/devtools/client/shared/test/unit/test_cssColorDatabase.js
+++ b/devtools/client/shared/test/unit/test_cssColorDatabase.js
@@ -1,16 +1,16 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Test that css-color-db matches platform.
 
 "use strict";
 
-var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 const {colorUtils} = require("devtools/shared/css/color");
 const {cssColors} = require("devtools/shared/css/color-db");
 const InspectorUtils = require("InspectorUtils");
 
 function isValid(colorName) {
   ok(colorUtils.isValidCSSColor(colorName),
      colorName + " is valid in database");

--- a/devtools/client/shared/test/unit/test_cubicBezier.js
+++ b/devtools/client/shared/test/unit/test_cubicBezier.js
@@ -2,17 +2,17 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 // Tests the CubicBezier API in the CubicBezierWidget module
 
-var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var {CubicBezier, parseTimingFunction} = require("devtools/client/shared/widgets/CubicBezierWidget");
 
 function run_test() {
   throwsWhenMissingCoordinates();
   throwsWhenIncorrectCoordinates();
   convertsStringCoordinates();
   coordinatesToStringOutputsAString();
   pointGettersReturnPointCoordinatesArrays();

--- a/devtools/client/shared/test/unit/test_escapeCSSComment.js
+++ b/devtools/client/shared/test/unit/test_escapeCSSComment.js
@@ -1,14 +1,14 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {escapeCSSComment, _unescapeCSSComment} = require("devtools/shared/css/parsing-utils");
 
 const TEST_DATA = [
   {
     input: "simple",
     expected: "simple"
   },
   {

--- a/devtools/client/shared/test/unit/test_parsePseudoClassesAndAttributes.js
+++ b/devtools/client/shared/test/unit/test_parsePseudoClassesAndAttributes.js
@@ -1,16 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {
   parsePseudoClassesAndAttributes,
   SELECTOR_ATTRIBUTE,
   SELECTOR_ELEMENT,
   SELECTOR_PSEUDO_CLASS
 } = require("devtools/shared/css/parsing-utils");
 
 const TEST_DATA = [

--- a/devtools/client/shared/test/unit/test_parseSingleValue.js
+++ b/devtools/client/shared/test/unit/test_parseSingleValue.js
@@ -1,16 +1,16 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {parseSingleValue} = require("devtools/shared/css/parsing-utils");
 const {isCssPropertyKnown} = require("devtools/server/actors/css-properties");
 
 const TEST_DATA = [
   {input: null, throws: true},
   {input: undefined, throws: true},
   {input: "", expected: {value: "", priority: ""}},
   {input: "  \t \t \n\n  ", expected: {value: "", priority: ""}},

--- a/devtools/client/shared/test/unit/test_rewriteDeclarations.js
+++ b/devtools/client/shared/test/unit/test_rewriteDeclarations.js
@@ -1,14 +1,14 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {RuleRewriter} = require("devtools/shared/css/parsing-utils");
 const {isCssPropertyKnown} = require("devtools/server/actors/css-properties");
 
 const TEST_DATA = [
   {
     desc: "simple set",
     input: "p:v;",
     instruction: {type: "set", name: "p", value: "N", priority: "",

--- a/devtools/client/shared/theme-switching.js
+++ b/devtools/client/shared/theme-switching.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/. */
 
 /* eslint-env browser */
 "use strict";
 (function () {
-  const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+  const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
   const Services = require("Services");
   const { gDevTools } = require("devtools/client/framework/devtools");
   const { appendStyleSheet } = require("devtools/client/shared/stylesheet-utils");
 
   let documentElement = document.documentElement;
 
   let os;
   let platform = navigator.platform;

--- a/devtools/client/shared/vendor/stringvalidator/tests/unit/head_stringvalidator.js
+++ b/devtools/client/shared/vendor/stringvalidator/tests/unit/head_stringvalidator.js
@@ -1,12 +1,12 @@
 "use strict";
 
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
-const { console } = Cu.import("resource://gre/modules/Console.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
+const { console } = ChromeUtils.import("resource://gre/modules/Console.jsm", {});
 
 this.validator = require("devtools/client/shared/vendor/stringvalidator/validator");
 
 function describe(suite, testFunc) {
   info(`\n                            Test suite: ${suite}`.toUpperCase());
   testFunc();
 }
 

--- a/devtools/client/shared/webpack/shims/test/test_stack.js
+++ b/devtools/client/shared/webpack/shims/test/test_stack.js
@@ -1,17 +1,17 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // There isn't really very much about the content stack.js that we can
 // test, but we'll do what we can.
 
 "use strict";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 
 const {
   callFunctionWithAsyncStack,
   getStack,
   describeNthCaller
 } = require("devtools/client/shared/webpack/shims/platform-stack-stub");
 
 function f3() {

--- a/devtools/client/shared/widgets/AbstractTreeItem.jsm
+++ b/devtools/client/shared/widgets/AbstractTreeItem.jsm
@@ -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 { require, loader } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require, loader } = ChromeUtils.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/old-event-emitter");
 
 ChromeUtils.defineModuleGetter(this, "console",
   "resource://gre/modules/Console.jsm");

--- a/devtools/client/shared/widgets/BreadcrumbsWidget.jsm
+++ b/devtools/client/shared/widgets/BreadcrumbsWidget.jsm
@@ -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 ENSURE_SELECTION_VISIBLE_DELAY = 50; // ms
 
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const { ViewHelpers, setNamedTimeout } = require("devtools/client/shared/widgets/view-helpers");
 const EventEmitter = require("devtools/shared/old-event-emitter");
 
 this.EXPORTED_SYMBOLS = ["BreadcrumbsWidget"];
 
 /**
  * A breadcrumb-like list of items.
  *

--- a/devtools/client/shared/widgets/SideMenuWidget.jsm
+++ b/devtools/client/shared/widgets/SideMenuWidget.jsm
@@ -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 SHARED_STRINGS_URI = "devtools/client/locales/shared.properties";
 
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 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/SimpleListWidget.jsm
+++ b/devtools/client/shared/widgets/SimpleListWidget.jsm
@@ -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 { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const { ViewHelpers } = require("devtools/client/shared/widgets/view-helpers");
 
 this.EXPORTED_SYMBOLS = ["SimpleListWidget"];
 
 /**
  * A very simple vertical list view.
  *
  * Note: this widget should be used in tandem with the WidgetMethods in

--- a/devtools/client/shared/widgets/VariablesView.jsm
+++ b/devtools/client/shared/widgets/VariablesView.jsm
@@ -8,17 +8,17 @@
 const DBG_STRINGS_URI = "devtools/client/locales/debugger.properties";
 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 { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
 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 { extend } = require("devtools/shared/extend");

--- a/devtools/client/shared/widgets/VariablesViewController.jsm
+++ b/devtools/client/shared/widgets/VariablesViewController.jsm
@@ -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";
 
-var {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+var {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 var {XPCOMUtils} = require("resource://gre/modules/XPCOMUtils.jsm");
 var {VariablesView} = require("resource://devtools/client/shared/widgets/VariablesView.jsm");
 var Services = require("Services");
 var promise = require("promise");
 var defer = require("devtools/shared/defer");
 var {LocalizationHelper, ELLIPSIS} = require("devtools/shared/l10n");
 
 Object.defineProperty(this, "WebConsoleUtils", {

--- a/devtools/client/sourceeditor/tern/tests/unit/head_tern.js
+++ b/devtools/client/sourceeditor/tern/tests/unit/head_tern.js
@@ -1,2 +1,2 @@
 "use strict";
-const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const { require } = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});

--- a/devtools/client/styleeditor/StyleEditorUI.jsm
+++ b/devtools/client/styleeditor/StyleEditorUI.jsm
@@ -2,17 +2,17 @@
 /* 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";
 
 this.EXPORTED_SYMBOLS = ["StyleEditorUI"];
 
-const {loader, require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {loader, require} = ChromeUtils.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/old-event-emitter");
 const {gDevTools} = require("devtools/client/framework/devtools");
 const {
   getString,

--- a/devtools/client/styleeditor/StyleEditorUtil.jsm
+++ b/devtools/client/styleeditor/StyleEditorUtil.jsm
@@ -14,17 +14,17 @@ this.EXPORTED_SYMBOLS = [
   "log",
   "text",
   "wire",
   "showFilePicker"
 ];
 
 const PROPERTIES_URL = "chrome://devtools/locale/styleeditor.properties";
 
-const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const {require} = ChromeUtils.import("resource://devtools/shared/Loader.jsm", {});
 const Services = require("Services");
 const console = require("resource://gre/modules/Console.jsm").console;
 const gStringBundle = Services.strings.createBundle(PROPERTIES_URL);
 
 /**
  * Returns a localized string with the given key name from the string bundle.
  *
  * @param name