--- a/browser/components/preferences/in-content/tests/browser_performance.js
+++ b/browser/components/preferences/in-content/tests/browser_performance.js
@@ -1,15 +1,13 @@
-add_task(function*() {
-  yield SpecialPowers.pushPrefEnv({set: [
-    ["browser.preferences.defaultPerformanceSettings.enabled", true],
-    ["dom.ipc.processCount", 4],
-    ["layers.acceleration.disabled", false],
-  ]});
-});
+SpecialPowers.pushPrefEnv({set: [
+  ["browser.preferences.defaultPerformanceSettings.enabled", true],
+  ["dom.ipc.processCount", 4],
+  ["layers.acceleration.disabled", false],
+]});
 
 add_task(function*() {
   let prefs = yield openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
   let doc = gBrowser.contentDocument;
   let useRecommendedPerformanceSettings = doc.querySelector("#useRecommendedPerformanceSettings");