--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1319,17 +1319,16 @@ var gBrowserInit = {
     TrackingProtection.init();
     CaptivePortalWatcher.init();
     ZoomUI.init(window);
 
     let mm = window.getGroupMessageManager("browsers");
     mm.loadFrameScript("chrome://browser/content/tab-content.js", true);
     mm.loadFrameScript("chrome://browser/content/content.js", true);
     mm.loadFrameScript("chrome://global/content/content-HybridContentTelemetry.js", true);
-    mm.loadFrameScript("chrome://global/content/manifestMessages.js", true);
 
     window.messageManager.addMessageListener("Browser:LoadURI", RedirectLoad);
 
     if (!gMultiProcessBrowser) {
       // There is a Content:Click message manually sent from content.
       Services.els.addSystemEventListener(gBrowser.tabpanels, "click",
         contentAreaClick, true);
     }

--- a/browser/base/content/tab-content.js
+++ b/browser/base/content/tab-content.js
@@ -85,16 +85,22 @@ addMessageListener("Browser:Reload", fun
 
 addMessageListener("MixedContent:ReenableProtection", function() {
   docShell.mixedContentChannel = null;
 });
 
 XPCOMUtils.defineLazyProxy(this, "LightweightThemeChildHelper",
   "resource:///modules/LightweightThemeChildHelper.jsm");
 
+XPCOMUtils.defineLazyProxy(this, "ManifestMessages", () => {
+  let tmp = {};
+  ChromeUtils.import("resource://gre/modules/ManifestMessages.jsm", tmp);
+  return new tmp.ManifestMessages(global);
+});
+
 let themeablePagesWhitelist = new Set([
   "about:home",
   "about:newtab",
   "about:welcome",
 ]);
 
 addEventListener("pageshow", function({ originalTarget }) {
   if (originalTarget.defaultView == content && themeablePagesWhitelist.has(content.document.documentURI)) {
@@ -512,8 +518,13 @@ addEventListener("MozAfterPaint", functi
 
 // Remove this once bug 1397365 is fixed.
 addEventListener("MozAfterPaint", function onFirstNonBlankPaint() {
   if (content.document.documentURI == "about:blank" && !content.opener)
     return;
   removeEventListener("MozAfterPaint", onFirstNonBlankPaint);
   sendAsyncMessage("Browser:FirstNonBlankPaint");
 });
+
+addMessageListener("DOM:WebManifest:hasManifestLink", ManifestMessages);
+addMessageListener("DOM:ManifestObtainer:Obtain", ManifestMessages);
+addMessageListener("DOM:Manifest:FireAppInstalledEvent", ManifestMessages);
+addMessageListener("DOM:WebManifest:fetchIcon", ManifestMessages);

rename from dom/ipc/manifestMessages.js
rename to dom/ipc/ManifestMessages.jsm
--- a/dom/ipc/manifestMessages.js
+++ b/dom/ipc/ManifestMessages.jsm
@@ -6,109 +6,107 @@
  * http://www.w3.org/TR/appmanifest/#obtaining
  *
  * It searches a top-level browsing context for
  * a <link rel=manifest> element. Then fetches
  * and processes the linked manifest.
  *
  * BUG: https://bugzilla.mozilla.org/show_bug.cgi?id=1083410
  */
-/*globals Task, ManifestObtainer, ManifestFinder, content, sendAsyncMessage, addMessageListener, Components*/
 "use strict";
-const {
-  utils: Cu,
-} = Components;
+
+var EXPORTED_SYMBOLS = ["ManifestMessages"];
+
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 
 ChromeUtils.defineModuleGetter(this, "ManifestObtainer",
-				  "resource://gre/modules/ManifestObtainer.jsm");
+                               "resource://gre/modules/ManifestObtainer.jsm");
 ChromeUtils.defineModuleGetter(this, "ManifestFinder",
-				  "resource://gre/modules/ManifestFinder.jsm");
+                               "resource://gre/modules/ManifestFinder.jsm");
 ChromeUtils.defineModuleGetter(this, "ManifestIcons",
-				  "resource://gre/modules/ManifestIcons.jsm");
+                               "resource://gre/modules/ManifestIcons.jsm");
+
+class ManifestMessages {
+  constructor(mm) {
+    this.mm = mm;
+  }
 
-const MessageHandler = {
-  registerListeners() {
-    addMessageListener(
-      "DOM:WebManifest:hasManifestLink",
-      this.hasManifestLink.bind(this)
-    );
-    addMessageListener(
-      "DOM:ManifestObtainer:Obtain",
-      this.obtainManifest.bind(this)
-    );
-    addMessageListener(
-      "DOM:Manifest:FireAppInstalledEvent",
-      this.fireAppInstalledEvent.bind(this)
-    );
-    addMessageListener(
-      "DOM:WebManifest:fetchIcon",
-      this.fetchIcon.bind(this)
-    );
-  },
+  receiveMessage(message) {
+    switch (message.name) {
+    case "DOM:WebManifest:hasManifestLink":
+      return this.hasManifestLink(message);
+    case "DOM:ManifestObtainer:Obtain":
+      return this.obtainManifest(message);
+    case "DOM:Manifest:FireAppInstalledEvent":
+      return this.fireAppInstalledEvent(message);
+    case "DOM:WebManifest:fetchIcon":
+      return this.fetchIcon(message);
+    }
+    return undefined;
+  }
 
   /**
-   * Check if the content document includes a link to a web manifest.
+   * Check if the this.mm.content document includes a link to a web manifest.
    * @param {Object} aMsg The IPC message, which is destructured to just
    *                      get the id.
    */
   hasManifestLink({data: {id}}) {
     const response = makeMsgResponse(id);
-    response.result = ManifestFinder.contentHasManifestLink(content);
+    response.result = ManifestFinder.contentHasManifestLink(this.mm.content);
     response.success = true;
-    sendAsyncMessage("DOM:WebManifest:hasManifestLink", response);
-  },
+    this.mm.sendAsyncMessage("DOM:WebManifest:hasManifestLink", response);
+  }
 
   /**
-   * Asynchronously obtains a web manifest from content by using the
+   * Asynchronously obtains a web manifest from this.mm.content by using the
    * ManifestObtainer and messages back the result.
    * @param {Object} aMsg The IPC message, which is destructured to just
    *                      get the id.
    */
   async obtainManifest({data: {id}}) {
     const response = makeMsgResponse(id);
     try {
-      response.result = await ManifestObtainer.contentObtainManifest(content);
+      response.result = await ManifestObtainer.contentObtainManifest(this.mm.content);
       response.success = true;
     } catch (err) {
       response.result = serializeError(err);
     }
-    sendAsyncMessage("DOM:ManifestObtainer:Obtain", response);
-  },
+    this.mm.sendAsyncMessage("DOM:ManifestObtainer:Obtain", response);
+  }
 
-  fireAppInstalledEvent({data: {id}}){
+  fireAppInstalledEvent({data: {id}}) {
     const ev = new Event("appinstalled");
     const response = makeMsgResponse(id);
-    if (!content || content.top !== content) {
+    if (!this.mm.content || this.mm.content.top !== this.mm.content) {
       const msg = "Can only dispatch install event on top-level browsing contexts.";
       response.result = serializeError(new Error(msg));
     } else {
       response.success = true;
-      content.dispatchEvent(ev);
+      this.mm.content.dispatchEvent(ev);
     }
-    sendAsyncMessage("DOM:Manifest:FireAppInstalledEvent", response);
-  },
+    this.mm.sendAsyncMessage("DOM:Manifest:FireAppInstalledEvent", response);
+  }
 
   /**
    * Given a manifest and an expected icon size, ask ManifestIcons
    * to fetch the appropriate icon and send along result
    */
   async fetchIcon({data: {id, manifest, iconSize}}) {
     const response = makeMsgResponse(id);
     try {
       response.result =
-        await ManifestIcons.contentFetchIcon(content, manifest, iconSize);
+        await ManifestIcons.contentFetchIcon(this.mm.content, manifest, iconSize);
       response.success = true;
     } catch (err) {
       response.result = serializeError(err);
     }
-    sendAsyncMessage("DOM:WebManifest:fetchIcon", response);
-  },
+    this.mm.sendAsyncMessage("DOM:WebManifest:fetchIcon", response);
+  }
+}
 
-};
 /**
  * Utility function to Serializes an JS Error, so it can be transferred over
  * the message channel.
  * FIX ME: https://bugzilla.mozilla.org/show_bug.cgi?id=1172586
  * @param  {Error} aError The error to serialize.
  * @return {Object} The serialized object.
  */
 function serializeError(aError) {
@@ -119,16 +117,14 @@ function serializeError(aError) {
     "stack": aError.stack,
     "message": aError.message,
     "name": aError.name
   };
   return clone;
 }
 
 function makeMsgResponse(aId) {
-    return {
-      id: aId,
-      success: false,
-      result: undefined
-    };
-  }
-
-MessageHandler.registerListeners();
+  return {
+    id: aId,
+    success: false,
+    result: undefined
+  };
+}

--- a/dom/ipc/jar.mn
+++ b/dom/ipc/jar.mn
@@ -3,9 +3,8 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 toolkit.jar:
         content/global/test-ipc.xul (test.xul)
         content/global/remote-test-ipc.js (remote-test.js)
         content/global/BrowserElementChild.js (../browser-element/BrowserElementChild.js)
         content/global/BrowserElementChildPreload.js (../browser-element/BrowserElementChildPreload.js)
         content/global/BrowserElementCopyPaste.js (../browser-element/BrowserElementCopyPaste.js)
-        content/global/manifestMessages.js (manifestMessages.js)

--- a/dom/ipc/moz.build
+++ b/dom/ipc/moz.build
@@ -8,16 +8,20 @@ with Files("**"):
     BUG_COMPONENT = ("Core", "DOM: Content Processes")
 
 XPIDL_SOURCES += [
     'nsIHangReport.idl',
 ]
 
 XPIDL_MODULE = 'dom'
 
+EXTRA_JS_MODULES += [
+    'ManifestMessages.jsm',
+]
+
 EXPORTS.mozilla.dom.ipc += [
     'IdType.h',
     'MemMapSnapshot.h',
     'SharedMap.h',
     'SharedMapChangeEvent.h',
     'SharedStringMap.h',
     'StringTable.h',
     'StructuredCloneData.h',