--- a/devtools/client/framework/toolbox.js
+++ b/devtools/client/framework/toolbox.js
@@ -3,17 +3,16 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const SOURCE_MAP_WORKER = "resource://devtools/client/shared/source-map/worker.js";
 const SOURCE_MAP_WORKER_ASSETS = "resource://devtools/client/shared/source-map/assets/";
 
 const MAX_ORDINAL = 99;
-const SHOW_ALL_ANONYMOUS_CONTENT_PREF = "devtools.inspector.showAllAnonymousContent";
 const SPLITCONSOLE_ENABLED_PREF = "devtools.toolbox.splitconsoleEnabled";
 const SPLITCONSOLE_HEIGHT_PREF = "devtools.toolbox.splitconsoleHeight";
 const DISABLE_AUTOHIDE_PREF = "ui.popup.disable_autohide";
 const HOST_HISTOGRAM = "DEVTOOLS_TOOLBOX_HOST";
 const CURRENT_THEME_SCALAR = "devtools.current_theme";
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 
 var {Ci, Cc} = require("chrome");
@@ -1684,17 +1683,17 @@ Toolbox.prototype = {
   /**
    * Ensure the tool with the given id is loaded.
    *
    * @param {string} id
    *        The id of the tool to load.
    */
   loadTool: function(id) {
     if (id === "inspector" && !this._inspector) {
-      this.initInspector();
+      return this.initInspector().then(() => this.loadTool(id));
     }
 
     let iframe = this.doc.getElementById("toolbox-panel-iframe-" + id);
     if (iframe) {
       const panel = this._toolPanels.get(id);
       return new Promise(resolve => {
         if (panel) {
           resolve(panel);
@@ -1728,21 +1727,17 @@ Toolbox.prototype = {
 
       // If no parent yet, append the frame into default location.
       if (!iframe.parentNode) {
         const vbox = this.doc.getElementById("toolbox-panel-" + id);
         vbox.appendChild(iframe);
         vbox.visibility = "visible";
       }
 
-      const onLoad = async () => {
-        if (id === "inspector") {
-          await this._initInspector;
-        }
-
+      const onLoad = () => {
         // Prevent flicker while loading by waiting to make visible until now.
         iframe.style.visibility = "visible";
 
         // Try to set the dir attribute as early as possible.
         this.setIframeDocumentDir(iframe);
 
         // The build method should return a panel instance, so events can
         // be fired with the panel as an argument. However, in order to keep
@@ -2674,43 +2669,32 @@ Toolbox.prototype = {
    */
   initInspector: function() {
     if (!this._initInspector) {
       this._initInspector = (async function() {
         // Temporary fix for bug #1493131 - inspector has a different life cycle
         // than most other fronts because it is closely related to the toolbox.
         // TODO: replace with getFront once inspector is separated from the toolbox
         this._inspector = this.target.getInspector();
-
-        await Promise.all([
-          this._getWalker(),
-          this._getHighlighter(),
-        ]);
-
+        const pref = "devtools.inspector.showAllAnonymousContent";
+        const showAllAnonymousContent = Services.prefs.getBoolPref(pref);
+        this._walker = await this._inspector.getWalker({ showAllAnonymousContent });
         this._selection = new Selection(this._walker);
-
         this._selection.on("new-node-front", this._onNewSelectedNodeFront);
+
         this.walker.on("highlighter-ready", this._highlighterReady);
         this.walker.on("highlighter-hide", this._highlighterHidden);
+
+        const autohide = !flags.testing;
+        this._highlighter = await this._inspector.getHighlighter(autohide);
       }.bind(this))();
     }
     return this._initInspector;
   },
 
-  _getWalker: async function() {
-    const showAllAnonymousContent = Services.prefs.getBoolPref(
-      SHOW_ALL_ANONYMOUS_CONTENT_PREF);
-    this._walker = await this._inspector.getWalker({ showAllAnonymousContent });
-  },
-
-  _getHighlighter: async function() {
-    const autohide = !flags.testing;
-    this._highlighter = await this._inspector.getHighlighter(autohide);
-  },
-
   _onNewSelectedNodeFront: function() {
     // Emit a "selection-changed" event when the toolbox.selection has been set
     // to a new node (or cleared). Currently used in the WebExtensions APIs (to
     // provide the `devtools.panels.elements.onSelectionChanged` event).
     this.emit("selection-changed");
   },
 
   _onInspectObject: function(packet) {

--- a/devtools/client/responsive.html/manager.js
+++ b/devtools/client/responsive.html/manager.js
@@ -2,33 +2,33 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const { Ci } = require("chrome");
 const promise = require("promise");
 const Services = require("Services");
+const asyncStorage = require("devtools/shared/async-storage");
 const EventEmitter = require("devtools/shared/event-emitter");
 
 loader.lazyRequireGetter(this, "DebuggerClient", "devtools/shared/client/debugger-client", true);
 loader.lazyRequireGetter(this, "DebuggerServer", "devtools/server/main", true);
 loader.lazyRequireGetter(this, "throttlingProfiles", "devtools/client/shared/components/throttling/profiles");
 loader.lazyRequireGetter(this, "SettingOnboardingTooltip", "devtools/client/responsive.html/setting-onboarding-tooltip");
 loader.lazyRequireGetter(this, "swapToInnerBrowser", "devtools/client/responsive.html/browser/swap", true);
 loader.lazyRequireGetter(this, "startup", "devtools/client/responsive.html/utils/window", true);
 loader.lazyRequireGetter(this, "message", "devtools/client/responsive.html/utils/message");
 loader.lazyRequireGetter(this, "showNotification", "devtools/client/responsive.html/utils/notification", true);
 loader.lazyRequireGetter(this, "l10n", "devtools/client/responsive.html/utils/l10n");
 loader.lazyRequireGetter(this, "EmulationFront", "devtools/shared/fronts/emulation", true);
 loader.lazyRequireGetter(this, "PriorityLevels", "devtools/client/shared/components/NotificationBox", true);
 loader.lazyRequireGetter(this, "TargetFactory", "devtools/client/framework/target", true);
 loader.lazyRequireGetter(this, "gDevTools", "devtools/client/framework/devtools", true);
 loader.lazyRequireGetter(this, "Telemetry", "devtools/client/shared/telemetry");
-loader.lazyRequireGetter(this, "asyncStorage", "devtools/shared/async-storage");
 
 const TOOL_URL = "chrome://devtools/content/responsive.html/index.xhtml";
 
 const RELOAD_CONDITION_PREF_PREFIX = "devtools.responsive.reloadConditions.";
 const RELOAD_NOTIFICATION_PREF = "devtools.responsive.reloadNotification.enabled";
 const SHOW_SETTING_TOOLTIP_PREF = "devtools.responsive.show-setting-tooltip";
 
 function debug(msg) {