From 17b11996aebb9b2792cfb3869382ac98a6c20a56 Mon Sep 17 00:00:00 2001
From: Georg Fritzsche <georg.fritzsche@googlemail.com>
Date: Thu, 17 Apr 2014 15:47:37 +0200
Subject: [PATCH] Bug 989137 - Part 18: Fix experiments uninit behavior.
 r=bsmedberg

---
 browser/experiments/Experiments.jsm              | 16 ++++++++++++++--
 .../test/browser/browser_experiments.js          |  1 +
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/browser/experiments/Experiments.jsm b/browser/experiments/Experiments.jsm
index 25118681ce0..a7dc7825472 100644
--- a/browser/experiments/Experiments.jsm
+++ b/browser/experiments/Experiments.jsm
@@ -327,6 +327,14 @@ Experiments.Policy.prototype = {
   },
 };
 
+function AlreadyShutdownError(message="already shut down") {
+  this.name = "AlreadyShutdownError";
+  this.message = message;
+}
+
+AlreadyShutdownError.prototype = new Error();
+AlreadyShutdownError.prototype.constructor = AlreadyShutdownError;
+
 /**
  * Manages the experiments and provides an interface to control them.
  */
@@ -434,7 +442,11 @@ Experiments.Experiments.prototype = {
 
     this._shutdown = true;
     if (this._mainTask) {
-      yield this._mainTask;
+      try {
+        yield this._mainTask;
+      } catch (e if e instanceof AlreadyShutdownError) {
+        // We error out of tasks after shutdown via that exception.
+      }
     }
 
     this._log.info("Completed uninitialization.");
@@ -457,7 +469,7 @@ Experiments.Experiments.prototype = {
    */
   _checkForShutdown: function() {
     if (this._shutdown) {
-      throw Error("uninit() already called");
+      throw new AlreadyShutdownError("uninit() already called");
     }
   },
 
diff --git a/toolkit/mozapps/extensions/test/browser/browser_experiments.js b/toolkit/mozapps/extensions/test/browser/browser_experiments.js
index d592a3f2b05..cbb072372ff 100644
--- a/toolkit/mozapps/extensions/test/browser/browser_experiments.js
+++ b/toolkit/mozapps/extensions/test/browser/browser_experiments.js
@@ -39,6 +39,7 @@ add_task(function* initializeState() {
     // this test running. We have to initialize the instance first, then
     // uninitialize it to prevent this.
     gExperiments = tmp.Experiments.instance();
+    yield gExperiments._mainTask;
     yield gExperiments.uninit();
   }
 });