Bug 1392653: Remove redundant LegacyExtensionUtils shutdown blocker. r=aswan

The base Extension class now handles adding shutdown blockers and waiting for
extension startup before beginning shutdown, so the redundant logic only
causes problems.

MozReview-Commit-ID: 2gBWlmIs1KQ

--HG--
extra : rebase_source : 404174754735b8477abf6f13d312bc6b3aebdb83

toolkit/components/extensions/LegacyExtensionsUtils.jsm

@@ -17,8 +17,6 @@ const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
-XPCOMUtils.defineLazyModuleGetter(this, "AsyncShutdown",
-                                  "resource://gre/modules/AsyncShutdown.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Extension",
                                   "resource://gre/modules/Extension.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "ExtensionChild",
@@ -208,28 +206,16 @@ class EmbeddedExtension {
    *
    * @returns {Promise<void>} a promise that is resolved when the shutdown has been done
    */
-  shutdown(reason) {
+  async shutdown(reason) {
     EmbeddedExtensionManager.untrackEmbeddedExtension(this);
 
-    // If there is a pending startup,  wait to be completed and then shutdown.
+    if (this.extension && !this.extension.hasShutdown) {
-    if (this.startupPromise) {
+      let {extension} = this;
-      let promise = this.startupPromise.then(() => {
+      this.extension = null;
-        return this.extension.shutdown(reason);
-      });
 
-      AsyncShutdown.profileChangeTeardown.addBlocker(
+      await extension.shutdown(reason);
-        `Legacy Extension Shutdown: ${this.addonId}`,
-        promise.catch(() => {}));
-
-      return promise;
     }
-
+    return undefined;
-    // Run shutdown now if the embedded webextension has been correctly started
-    if (this.extension && this.started && !this.extension.hasShutdown) {
-      this.extension.shutdown(reason);
-    }
-
-    return Promise.resolve();
   }
 }