diff --git a/dom/webidl/AddonManager.webidl b/dom/webidl/AddonManager.webidl
index 714cf28c3e18..1701b575828d 100644
--- a/dom/webidl/AddonManager.webidl
+++ b/dom/webidl/AddonManager.webidl
@@ -3,9 +3,8 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-/* We need a JSImplementation but cannot get one without a contract ID.
-   Since Addon and AddonInstall are only ever created from JS they don't need
-   real contract IDs. */
+/* We need a JSImplementation but cannot get one without a contract ID. Since
+   This object is only ever created from JS we don't need a real contract ID. */
 [ChromeOnly, JSImplementation="dummy"]
 interface Addon {
   // The add-on's ID.
@@ -24,27 +23,6 @@ interface Addon {
   readonly attribute boolean isEnabled;
   // If the add-on is currently active in the browser.
   readonly attribute boolean isActive;
-
-  Promise<boolean> uninstall();
-};
-
-[ChromeOnly, JSImplementation="dummy"]
-interface AddonInstall : EventTarget {
-  // One of the STATE_* symbols from AddonManager.jsm
-  readonly attribute DOMString state;
-  // One of the ERROR_* symbols from AddonManager.jsm, or null
-  readonly attribute DOMString? error;
-  // How many bytes have been downloaded
-  readonly attribute long long progress;
-  // How many total bytes will need to be downloaded or -1 if unknown
-  readonly attribute long long maxProgress;
-
-  Promise<void> install();
-  Promise<void> cancel();
-};
-
-dictionary addonInstallOptions {
-  required DOMString url;
 };
 
 [HeaderFile="mozilla/AddonManagerWebAPI.h",
@@ -60,13 +38,4 @@ interface AddonManager {
    * @return A promise. It will resolve to an Addon if the add-on is installed.
    */
   Promise<Addon> getAddonByID(DOMString id);
-
-  /**
-   * Creates an AddonInstall object for a given URL.
-   *
-   * @param options
-   *        Only one supported option: 'url', the URL of the addon to install.
-   * @return A promise that resolves to an instance of AddonInstall.
-   */
-  Promise<AddonInstall> createInstall(optional addonInstallOptions options);
 };
diff --git a/toolkit/mozapps/extensions/amWebAPI.js b/toolkit/mozapps/extensions/amWebAPI.js
index 68b468ca982c..e83a9ccadb84 100644
--- a/toolkit/mozapps/extensions/amWebAPI.js
+++ b/toolkit/mozapps/extensions/amWebAPI.js
@@ -55,16 +55,11 @@ const APIBroker = {
 
 APIBroker.init();
 
-function Addon(win, properties) {
+function Addon(properties) {
   // We trust the webidl binding to broker access to our properties.
   for (let key of Object.keys(properties)) {
     this[key] = properties[key];
   }
-
-  this.uninstall = function() {
-    let err = new win.Error("not yet implemented");
-    return win.Promise.reject(err);
-  };
 }
 
 /**
@@ -102,14 +97,9 @@ WebAPI.prototype = {
 
   getAddonByID: WebAPITask(function*(id) {
     let addonInfo = yield APIBroker.sendRequest("getAddonByID", id);
-    return addonInfo ? new Addon(this.window, addonInfo) : null;
+    return addonInfo ? new Addon(addonInfo) : null;
   }),
 
-  createInstall() {
-    let err = new this.window.Error("not yet implemented");
-    return this.window.Promise.reject(err);
-  },
-
   classID: Components.ID("{8866d8e3-4ea5-48b7-a891-13ba0ac15235}"),
   contractID: "@mozilla.org/addon-web-api/manager;1",
   QueryInterface: XPCOMUtils.generateQI([Ci.nsISupports, Ci.nsIDOMGlobalPropertyInitializer])