diff --git a/common/modules/addons.jsm b/common/modules/addons.jsm
index 741c07e9..2e52a9aa 100644
--- a/common/modules/addons.jsm
+++ b/common/modules/addons.jsm
@@ -492,127 +492,7 @@ var Addons = Module("addons", {
     }
 });
 
-if (!services.has("extensionManager"))
-    Components.utils.import("resource://gre/modules/AddonManager.jsm", this);
-else
-    var AddonManager = {
-        PERM_CAN_UNINSTALL: 1,
-        PERM_CAN_ENABLE: 2,
-        PERM_CAN_DISABLE: 4,
-        PERM_CAN_UPGRADE: 8,
-
-        getAddonByID: function (id, callback) {
-            callback = callback || util.identity;
-            addon = services.extensionManager.getItemForID(id);
-            if (addon)
-                addon = this.wrapAddon(addon);
-            return callback(addon);
-        },
-
-        wrapAddon: function wrapAddon(addon) {
-            addon = Object.create(addon.QueryInterface(Ci.nsIUpdateItem));
-
-            ["aboutURL", "creator", "description", "developers",
-             "homepageURL", "installDate", "optionsURL",
-             "releaseNotesURI", "updateDate"].forEach(function (item) {
-                memoize(addon, item, function (item) this.getProperty(item));
-            });
-
-            update(addon, {
-
-                get permissions() 1 | (this.userDisabled ? 2 : 4),
-
-                appDisabled: false,
-
-                getProperty: function getProperty(property) {
-                    let resource = services.rdf.GetResource("urn:mozilla:item:" + this.id);
-
-                    if (resource) {
-                        let target = services.extensionManager.datasource.GetTarget(resource,
-                            services.rdf.GetResource("http://www.mozilla.org/2004/em-rdf#" + property), true);
-
-                        if (target && target instanceof Ci.nsIRDFLiteral)
-                            return target.Value;
-                    }
-
-                    return "";
-                },
-
-                installLocation: Class.Memoize(function () services.extensionManager.getInstallLocation(this.id)),
-                getResourceURI: function getResourceURI(path) {
-                    let file = this.installLocation.getItemFile(this.id, path);
-                    return services.io.newFileURI(file);
-                },
-
-                get isActive() this.getProperty("isDisabled") != "true",
-
-                uninstall: function uninstall() {
-                    services.extensionManager.uninstallItem(this.id);
-                },
-
-                get userDisabled() this.getProperty("userDisabled") === "true",
-                set userDisabled(val) {
-                    services.extensionManager[val ? "disableItem" : "enableItem"](this.id);
-                }
-            });
-
-            return addon;
-        },
-
-        getAddonsByTypes: function (types, callback) {
-            let res = [];
-            for (let [, type] in Iterator(types))
-                for (let [, item] in Iterator(services.extensionManager
-                            .getItemList(Ci.nsIUpdateItem["TYPE_" + type.toUpperCase()], {})))
-                    res.push(this.wrapAddon(item));
-
-            if (callback)
-                util.timeout(function () { callback(res); });
-            return res;
-        },
-
-        getInstallForFile: function (file, callback, mimetype) {
-            callback({
-                addListener: function () {},
-                install: function () {
-                    services.extensionManager.installItemFromFile(file, "app-profile");
-                }
-            });
-        },
-
-        getInstallForURL: function (url, callback, mimetype) {
-            util.assert(false, _("error.unavailable", config.host, services.runtime.version));
-        },
-
-        observers: [],
-        addAddonListener: function (listener) {
-            observer.listener = listener;
-            function observer(subject, topic, data) {
-                if (subject instanceof Ci.nsIUpdateItem)
-                    subject = AddonManager.wrapAddon(subject);
-
-                if (data === "item-installed")
-                    listener.onInstalling(subject, true);
-                else if (data === "item-uninstalled")
-                    listener.onUnistalling(subject, true);
-                else if (data === "item-upgraded")
-                    listener.onInstalling(subject, true);
-                else if (data === "item-enabled")
-                    listener.onEnabling(subject, true);
-                else if (data === "item-disabled")
-                    listener.onDisabling(subject, true);
-            }
-            services.observer.addObserver(observer, "em-action-requested", false);
-            this.observers.push(observer);
-        },
-        removeAddonListener: function (listener) {
-            this.observers = this.observers.filter(function (observer) {
-                if (observer.listener !== listener)
-                    return true;
-                services.observer.removeObserver(observer, "em-action-requested");
-            });
-        }
-    };
+Components.utils.import("resource://gre/modules/AddonManager.jsm", this);
 
 endModule();
 
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index a3494b8b..abdd25ff 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -20,13 +20,6 @@ let { __lookupGetter__, __lookupSetter__, __defineGetter__, __defineSetter__,
 if (typeof XPCSafeJSObjectWrapper === "undefined")
     this.XPCSafeJSObjectWrapper = XPCNativeWrapper;
 
-if (!XPCNativeWrapper.unwrap)
-    XPCNativeWrapper.unwrap = function unwrap(obj) {
-        if (hasOwnProperty.call(obj, "wrappedJSObject"))
-            return obj.wrappedJSObject;
-        return obj;
-    };
-
 let getGlobalForObject = Cu.getGlobalForObject || function (obj) obj.__parent__;
 
 function require(module, target) JSMLoader.load(module, target);
@@ -208,7 +201,6 @@ function debuggerProperties(obj) {
  * @returns {Generator}
  */
 function prototype(obj)
-    /* Temporary hack: */ typeof obj === "xml" || obj.__proto__ !== obj.__proto__ ? null :
     obj.__proto__ || Object.getPrototypeOf(obj) ||
     XPCNativeWrapper.unwrap(obj).__proto__ ||
     Object.getPrototypeOf(XPCNativeWrapper.unwrap(obj));