deleted file mode 100644
--- a/browser/components/extensions/prepare.py
+++ /dev/null
@@ -1,83 +0,0 @@
-#!/usr/bin/env python
-# 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/.
-
-import argparse
-import json
-import uuid
-import sys
-import os.path
-
-parser = argparse.ArgumentParser(description='Create install.rdf from manifest.json')
-parser.add_argument('--locale')
-parser.add_argument('--profile')
-parser.add_argument('--uuid')
-parser.add_argument('dir')
-args = parser.parse_args()
-
-manifestFile = os.path.join(args.dir, 'manifest.json')
-manifest = json.load(open(manifestFile))
-
-locale = args.locale
-if not locale:
-    locale = manifest.get('default_locale', 'en-US')
-
-def process_locale(s):
-    if s.startswith('__MSG_') and s.endswith('__'):
-        tag = s[6:-2]
-        path = os.path.join(args.dir, '_locales', locale, 'messages.json')
-        data = json.load(open(path))
-        return data[tag]['message']
-    else:
-        return s
-
-id = args.uuid
-if not id:
-    id = '{' + str(uuid.uuid4()) + '}'
-
-name = process_locale(manifest['name'])
-desc = process_locale(manifest['description'])
-version = manifest['version']
-
-installFile = open(os.path.join(args.dir, 'install.rdf'), 'w')
-print >>installFile, '<?xml version="1.0"?>'
-print >>installFile, '<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"'
-print >>installFile, '     xmlns:em="http://www.mozilla.org/2004/em-rdf#">'
-print >>installFile
-print >>installFile, '  <Description about="urn:mozilla:install-manifest">'
-print >>installFile, '    <em:id>{}</em:id>'.format(id)
-print >>installFile, '    <em:type>2</em:type>'
-print >>installFile, '    <em:name>{}</em:name>'.format(name)
-print >>installFile, '    <em:description>{}</em:description>'.format(desc)
-print >>installFile, '    <em:version>{}</em:version>'.format(version)
-print >>installFile, '    <em:bootstrap>true</em:bootstrap>'
-
-print >>installFile, '    <em:targetApplication>'
-print >>installFile, '      <Description>'
-print >>installFile, '        <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>'
-print >>installFile, '        <em:minVersion>4.0</em:minVersion>'
-print >>installFile, '        <em:maxVersion>50.0</em:maxVersion>'
-print >>installFile, '      </Description>'
-print >>installFile, '    </em:targetApplication>'
-
-print >>installFile, '  </Description>'
-print >>installFile, '</RDF>'
-installFile.close()
-
-bootstrapPath = os.path.join(os.path.dirname(sys.argv[0]), 'bootstrap.js')
-data = open(bootstrapPath).read()
-boot = open(os.path.join(args.dir, 'bootstrap.js'), 'w')
-boot.write(data)
-boot.close()
-
-if args.profile:
-    os.system('mkdir -p {}/extensions'.format(args.profile))
-    output = open(args.profile + '/extensions/' + id, 'w')
-    print >>output, os.path.realpath(args.dir)
-    output.close()
-else:
-    dir = os.path.realpath(args.dir)
-    if dir[-1] == os.sep:
-        dir = dir[:-1]
-    os.system('cd "{}"; zip ../"{}".xpi -r *'.format(args.dir, os.path.basename(dir)))

--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -136,16 +136,20 @@ let Management = {
     this.emitter.on(hook, callback);
   },
 
   // Ask to run all the callbacks that are registered for a given hook.
   emit(hook, ...args) {
     this.lazyInit();
     this.emitter.emit(hook, ...args);
   },
+
+  off(hook, callback) {
+    this.emitter.off(hook, callback);
+  }
 };
 
 // A MessageBroker that's used to send and receive messages for
 // extension pages (which run in the chrome process).
 let globalBroker = new MessageBroker([Services.mm, Services.ppmm]);
 
 // An extension page is an execution context for any extension content
 // that runs in the chrome process. It's used for background pages
@@ -524,23 +528,23 @@ Extension.prototype = {
     this.onShutdown.add(obj);
   },
 
   forgetOnClose(obj) {
     this.onShutdown.delete(obj);
   },
 
   startup() {
-    GlobalManager.init(this);
-
     return Promise.all([this.readManifest(), this.readLocaleMessages()]).then(([manifest, messages]) => {
       if (this.hasShutdown) {
         return;
       }
 
+      GlobalManager.init(this);
+
       this.manifest = manifest;
       this.localeMessages = messages;
 
       Management.emit("startup", this);
 
       this.runManifest(manifest);
     }).catch(e => {
       dump(`Extension error: ${e} ${e.fileName}:${e.lineNumber}\n`);

rename from browser/components/extensions/bootstrap.js
rename to toolkit/mozapps/extensions/internal/WebExtensionBootstrap.js
--- a/browser/components/extensions/bootstrap.js
+++ b/toolkit/mozapps/extensions/internal/WebExtensionBootstrap.js
@@ -3,18 +3,26 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 Components.utils.import("resource://gre/modules/Extension.jsm");
 
 let extension;
 
+function install(data, reason)
+{
+}
+
 function startup(data, reason)
 {
   extension = new Extension(data);
   extension.startup();
 }
 
 function shutdown(data, reason)
 {
   extension.shutdown();
 }
+
+function uninstall(data, reason)
+{
+}

--- a/toolkit/mozapps/extensions/internal/XPIProvider.jsm
+++ b/toolkit/mozapps/extensions/internal/XPIProvider.jsm
@@ -4623,16 +4623,18 @@ this.XPIProvider = {
                                     metadata: { addonID: aId } });
       logger.error("Attempted to load bootstrap scope from missing directory " + aFile.path);
       return;
     }
 
     let uri = getURIForResourceInFile(aFile, "bootstrap.js").spec;
     if (aType == "dictionary")
       uri = "resource://gre/modules/addons/SpellCheckDictionaryBootstrap.js"
+    else if (aType == "webextension")
+      uri = "resource://gre/modules/addons/WebExtensionBootstrap.js"
 
     this.bootstrapScopes[aId] =
       new Cu.Sandbox(principal, { sandboxName: uri,
                                   wantGlobalProperties: ["indexedDB"],
                                   addonId: aId,
                                   metadata: { addonID: aId, URI: uri } });
 
     let loader = Cc["@mozilla.org/moz/jssubscript-loader;1"].

--- a/toolkit/mozapps/extensions/internal/moz.build
+++ b/toolkit/mozapps/extensions/internal/moz.build
@@ -8,16 +8,17 @@ EXTRA_JS_MODULES.addons += [
     'AddonLogging.jsm',
     'AddonRepository.jsm',
     'AddonRepository_SQLiteMigrator.jsm',
     'AddonUpdateChecker.jsm',
     'Content.js',
     'GMPProvider.jsm',
     'LightweightThemeImageOptimizer.jsm',
     'SpellCheckDictionaryBootstrap.js',
+    'WebExtensionBootstrap.js',
 ]
 
 # Don't ship unused providers on Android
 if CONFIG['MOZ_WIDGET_TOOLKIT'] != 'android':
     EXTRA_JS_MODULES.addons += [
         'PluginProvider.jsm',
     ]
 

--- a/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js
@@ -5,47 +5,92 @@
 const ID = "webextension1@tests.mozilla.org";
 
 const profileDir = gProfD.clone();
 profileDir.append("extensions");
 
 createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "42");
 startupManager();
 
+const { GlobalManager, Management } = Components.utils.import("resource://gre/modules/Extension.jsm", {});
+
+function promiseAddonStartup() {
+  return new Promise(resolve => {
+    let listener = (extension) => {
+      Management.off("startup", listener);
+      resolve(extension);
+    }
+
+    Management.on("startup", listener);
+  });
+}
+
 add_task(function*() {
-  yield promiseInstallAllFiles([do_get_addon("webextension_1")], true);
+  do_check_eq(GlobalManager.count, 0);
+  do_check_false(GlobalManager.extensionMap.has(ID));
+
+  yield Promise.all([
+    promiseInstallAllFiles([do_get_addon("webextension_1")], true),
+    promiseAddonStartup()
+  ]);
+
+  do_check_eq(GlobalManager.count, 1);
+  do_check_true(GlobalManager.extensionMap.has(ID));
 
   let addon = yield promiseAddonByID(ID);
   do_check_neq(addon, null);
   do_check_eq(addon.version, "1.0");
   do_check_eq(addon.name, "Web Extension Name");
   do_check_true(addon.isCompatible);
   do_check_false(addon.appDisabled);
   do_check_true(addon.isActive);
   do_check_eq(addon.type, "extension");
   do_check_eq(addon.signedState, AddonManager.SIGNEDSTATE_MISSING);
 
   // Should persist through a restart
-  yield promiseRestartManager();
+  yield promiseShutdownManager();
+
+  do_check_eq(GlobalManager.count, 0);
+  do_check_false(GlobalManager.extensionMap.has(ID));
+
+  startupManager();
+  yield promiseAddonStartup();
+
+  do_check_eq(GlobalManager.count, 1);
+  do_check_true(GlobalManager.extensionMap.has(ID));
 
   addon = yield promiseAddonByID(ID);
   do_check_neq(addon, null);
   do_check_eq(addon.version, "1.0");
   do_check_eq(addon.name, "Web Extension Name");
   do_check_true(addon.isCompatible);
   do_check_false(addon.appDisabled);
   do_check_true(addon.isActive);
   do_check_eq(addon.type, "extension");
   do_check_eq(addon.signedState, AddonManager.SIGNEDSTATE_MISSING);
 
   let file = getFileForAddon(profileDir, ID);
   do_check_true(file.exists());
 
+  addon.userDisabled = true;
+
+  do_check_eq(GlobalManager.count, 0);
+  do_check_false(GlobalManager.extensionMap.has(ID));
+
+  addon.userDisabled = false;
+  yield promiseAddonStartup();
+
+  do_check_eq(GlobalManager.count, 1);
+  do_check_true(GlobalManager.extensionMap.has(ID));
+
   addon.uninstall();
 
+  do_check_eq(GlobalManager.count, 0);
+  do_check_false(GlobalManager.extensionMap.has(ID));
+
   yield promiseShutdownManager();
 });
 
 // Writing the manifest direct to the profile should work
 add_task(function*() {
   writeWebManifestForExtension({
     name: "Web Extension Name",
     version: "1.0",