--- a/toolkit/components/normandy/content/AboutPages.jsm
+++ b/toolkit/components/normandy/content/AboutPages.jsm
@@ -15,18 +15,16 @@ ChromeUtils.defineModuleGetter(
 ChromeUtils.defineModuleGetter(
   this, "RecipeRunner", "resource://normandy/lib/RecipeRunner.jsm",
 );
 
 var EXPORTED_SYMBOLS = ["AboutPages"];
 
 const SHIELD_LEARN_MORE_URL_PREF = "app.normandy.shieldLearnMoreUrl";
 
-const FRAME_SCRIPT = "resource://normandy-content/shield-content-frame.js";
-
 /**
  * Class for managing an about: page that Normandy provides. Adapted from
  * browser/extensions/pocket/content/AboutPocket.jsm.
  *
  * @implements nsIFactory
  * @implements nsIAboutModule
  */
 class AboutPage {
@@ -56,26 +54,22 @@ class AboutPage {
 }
 AboutPage.prototype.QueryInterface = ChromeUtils.generateQI([Ci.nsIAboutModule]);
 
 /**
  * The module exported by this file.
  */
 var AboutPages = {
   async init() {
-    // Load scripts in content processes and tabs
-    Services.mm.loadFrameScript(FRAME_SCRIPT, true);
-
     // Register about: pages and their listeners
     this.aboutStudies.registerParentListeners();
 
     CleanupManager.addCleanupHandler(() => {
       // Stop loading processs scripts and notify existing scripts to clean up.
       Services.ppmm.broadcastAsyncMessage("Shield:ShuttingDown");
-      Services.mm.removeDelayedFrameScript(FRAME_SCRIPT);
       Services.mm.broadcastAsyncMessage("Shield:ShuttingDown");
 
       // Clean up about pages
       this.aboutStudies.unregisterParentListeners();
     });
   },
 };
 

rename from toolkit/components/normandy/content/shield-content-frame.js
rename to toolkit/components/normandy/content/ShieldFrameListener.jsm
--- a/toolkit/components/normandy/content/shield-content-frame.js
+++ b/toolkit/components/normandy/content/ShieldFrameListener.jsm
@@ -1,28 +1,27 @@
 /* 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 EXPORTED_SYMBOLS = ["ShieldFrameListener"];
+
 /**
  * Listen for DOM events bubbling up from the about:studies page, and perform
  * privileged actions in response to them. If we need to do anything that the
  * content process can't handle (such as reading IndexedDB), we send a message
  * to the parent process and handle it there.
  *
  * This file is loaded as a frame script. It will be loaded once per tab that
  * is opened.
  */
 
-/* global content addMessageListener removeMessageListener sendAsyncMessage */
-
 ChromeUtils.import("resource://gre/modules/Services.jsm");
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
-ChromeUtils.import("resource://gre/modules/AppConstants.jsm");
 
 const frameGlobal = {};
 ChromeUtils.defineModuleGetter(
   frameGlobal, "AboutPages", "resource://normandy-content/AboutPages.jsm",
 );
 
 XPCOMUtils.defineLazyGetter(this, "gBrandBundle", function() {
   return Services.strings.createBundle("chrome://branding/locale/brand.properties");
@@ -33,41 +32,45 @@ XPCOMUtils.defineLazyGetter(this, "gStri
 });
 
 /**
  * Handles incoming events from the parent process and about:studies.
  * @implements nsIMessageListener
  * @implements EventListener
  */
 class ShieldFrameListener {
+  constructor(mm) {
+    this.mm = mm;
+  }
+
   handleEvent(event) {
     // Abort if the current page isn't about:studies.
     if (!this.ensureTrustedOrigin()) {
       return;
     }
 
     // We waited until after we received an event to register message listeners
     // in order to save resources for tabs that don't ever load about:studies.
-    addMessageListener("Shield:ShuttingDown", this);
-    addMessageListener("Shield:ReceiveStudyList", this);
-    addMessageListener("Shield:ReceiveStudiesEnabled", this);
+    this.mm.addMessageListener("Shield:ShuttingDown", this);
+    this.mm.addMessageListener("Shield:ReceiveStudyList", this);
+    this.mm.addMessageListener("Shield:ReceiveStudiesEnabled", this);
 
     switch (event.detail.action) {
       // Actions that require the parent process
       case "GetRemoteValue:StudyList":
-        sendAsyncMessage("Shield:GetStudyList");
+        this.mm.sendAsyncMessage("Shield:GetStudyList");
         break;
       case "RemoveStudy":
-        sendAsyncMessage("Shield:RemoveStudy", event.detail.data);
+        this.mm.sendAsyncMessage("Shield:RemoveStudy", event.detail.data);
         break;
       case "GetRemoteValue:StudiesEnabled":
-        sendAsyncMessage("Shield:GetStudiesEnabled");
+        this.mm.sendAsyncMessage("Shield:GetStudiesEnabled");
         break;
       case "NavigateToDataPreferences":
-        sendAsyncMessage("Shield:OpenDataPreferences");
+        this.mm.sendAsyncMessage("Shield:OpenDataPreferences");
         break;
       // Actions that can be performed in the content process
       case "GetRemoteValue:ShieldLearnMoreHref":
         this.triggerPageCallback(
           "ReceiveRemoteValue:ShieldLearnMoreHref",
           frameGlobal.AboutPages.aboutStudies.getShieldLearnMoreHref()
         );
         break;
@@ -89,17 +92,17 @@ class ShieldFrameListener {
     }
   }
 
   /**
    * Check that the current webpage's origin is about:studies.
    * @return {Boolean}
    */
   ensureTrustedOrigin() {
-    return content.document.documentURI.startsWith("about:studies");
+    return this.mm.content.document.documentURI.startsWith("about:studies");
   }
 
   /**
    * Handle messages from the parent process.
    * @param {Object} message
    *   See the nsIMessageListener docs.
    */
   receiveMessage(message) {
@@ -122,24 +125,24 @@ class ShieldFrameListener {
    * @param {Object} detail
    */
   triggerPageCallback(type, detail) {
     // Do not communicate with untrusted pages.
     if (!this.ensureTrustedOrigin()) {
       return;
     }
 
+    let {content} = this.mm;
+
     // Clone details and use the event class from the unprivileged context.
     const event = new content.document.defaultView.CustomEvent(type, {
       bubbles: true,
       detail: Cu.cloneInto(detail, content.document.defaultView),
     });
     content.document.dispatchEvent(event);
   }
 
   onShutdown() {
-    removeMessageListener("Shield:SendStudyList", this);
-    removeMessageListener("Shield:ShuttingDown", this);
-    removeEventListener("Shield", this);
+    this.mm.removeMessageListener("Shield:SendStudyList", this);
+    this.mm.removeMessageListener("Shield:ShuttingDown", this);
+    this.mm.removeEventListener("Shield", this);
   }
 }
-
-addEventListener("ShieldPageEvent", new ShieldFrameListener(), false, true);

--- a/toolkit/content/browser-content.js
+++ b/toolkit/content/browser-content.js
@@ -32,16 +32,22 @@ XPCOMUtils.defineLazyServiceGetter(this,
 var global = this;
 
 XPCOMUtils.defineLazyProxy(this, "PopupBlocking", () => {
   let tmp = {};
   ChromeUtils.import("resource://gre/modules/PopupBlocking.jsm", tmp);
   return new tmp.PopupBlocking(global);
 });
 
+XPCOMUtils.defineLazyProxy(this, "ShieldFrameListener", () => {
+  let tmp = {};
+  ChromeUtils.import("resource://normandy-content/ShieldFrameListener.jsm", tmp);
+  return new tmp.ShieldFrameListener(global);
+});
+
 XPCOMUtils.defineLazyProxy(this, "SelectionSourceContent",
   "resource://gre/modules/SelectionSourceContent.jsm");
 
 XPCOMUtils.defineLazyProxy(this, "WebChannelContent",
   "resource://gre/modules/WebChannelContent.jsm");
 
 XPCOMUtils.defineLazyProxy(this, "DateTimePickerContent", () => {
   let tmp = {};
@@ -518,8 +524,10 @@ let ExtFind = {
       case "ext-Finder:clearHighlighting":
         this._findContent.highlighter.highlight(false);
         break;
     }
   },
 };
 
 ExtFind.init();
+
+addEventListener("ShieldPageEvent", ShieldFrameListener, false, true);